Note: Descriptions are shown in the official language in which they were submitted.
CA 02803344 2014-09-19
HVAC AIR TEMPERATURE SAFETY SYSTEM
FIELD OF THE INVENTION
[0003] The present invention relates to heating, ventilation, and air
conditioning (HVAC)
systems. More specifically, the present invention relates to a system and
method for
HVAC system operation in the event of an HVAC control system or thermostat
failure.
BACKGROUND
[0004] Thermostats for an HVAC system are generally known in the art. A
thermostat is
a component of an HVAC system which can regulate the ambient temperature of an
environment to be near a desired or targeted set point temperature. Generally,
a
thermostat will provide instructions to the HVAC system to provide heated
and/or cooled
air to the environment. The instructions are generally based upon targeting a
desired set
point temperature in the environment. For example, if the ambient temperature
of an
environment is below a desired or targeted set point temperature and the
thermostat
determines that the ambient temperature should be raised, the thermostat will
signal to the
HVAC system to provide heated air. As an additional example, if the ambient
temperature
of an environment is above a desired or targeted set point temperature and the
thermostat
determines that the ambient temperature should be lowered, the thermostat will
signal to
the HVAC system to provide cooled air.
[0005] However, known thermostats or control systems for an HVAC system have
certain
limitations. For example, in instances where a thermostat or control system
fails or ceases
to properly regulate the ambient temperature of an environment, the HVAC
system will
not receive further operational instructions from the thermostat or control
system. This
can result in unsafe conditions in the environment to be regulated by the HVAC
system,
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such as extremely high temperatures (for example, in excess of 100 F) or
extremely low
temperatures (for example, below 40 F). The unsafe conditions caused by
extreme
temperatures can cause damage to the associated HVAC system. In addition,
extreme
temperatures can lead to damage to a home, building, or structure which houses
the
HVAC system. Such damage may include, but is not limited to, broken water
pipes
caused by freezing due to extreme low temperatures, or mold, mildew, or
structural
damage caused by high humidity due to extreme high temperatures.
[0006] For example, in a situation where the HVAC system was not operating at
the time
of thermostat failure, the result can be a prolonged amount of time where the
HVAC
system does not operate. During this prolonged time of HVAC system non-
operation, the
ambient temperature in the environment regulated by the HVAC system can
increase or
decrease based upon the ambient temperature outside of the environment
regulated by the
HVAC system, such as the temperature outdoors or outside. In times of higher
outdoor
temperatures, the ambient temperature in the environment regulated by the HVAC
system
can become very high (for example, in excess of 100 F). In times of lower
outdoor
temperatures, the ambient temperature in the environment regulated by the HVAC
system
can become very low (for example, below 40 F).
[0007] As another example, in a situation where the HVAC system was operating
at the
time of thermostat failure, the result can be a prolonged amount of time where
the HVAC
system does operate. This is known as a system "runaway" condition. During
this
prolonged time of HVAC system operation, the ambient temperature in the
environment
regulated by the HVAC system can continually increase or decrease. If the HVAC
system
is providing heated air, the ambient temperature in the environment regulated
by the
HVAC system can become very high (for example, in excess of 100 F). If the
HVAC
system is providing cooled air, the ambient temperature in the environment
regulated by
the HVAC system can become very low (for example, below 40 F).
SUMMARY OF THE DESCRIPTION
[0008] The present invention provides an HVAC air temperature safety control
system
which enables the HVAC system to continue to operate in situations of
thermostat failure.
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The safety control system provides for HVAC operation in periods of
predetermined low
temperatures to prevent freezing of an environment regulated by the HVAC
system due to
thermostat or other HVAC control system failure. In addition, the safety
control system
provides for HVAC operation in periods of predetermined high temperatures to
prevent
overheating of an environment regulated by the HVAC system due to thermostat
or other
HVAC control system failure.
[0009] A system for operating an HVAC system is provided. The system includes
determining whether a failure of a thermostat in operable communication with
an HVAC
system has occurred, activating a safety control program upon determining the
thermostat
failure has occurred, wherein the safety control program resides on
electronically readable
storage medium in operable communication with the HVAC system, resetting a
first timer,
determining if an amount of time in the first timer exceeds a first time
period, increasing
the amount of time remaining in the first timer by a first time increment if
the amount of
time remaining in the first timer does not exceed the first time period,
activating an HVAC
system blower when the time remaining first timer exceeds the first time
period,
measuring a temperature of conditioned air on a temperature sensor, wherein
the
temperature sensor is in communication with the safety control program and is
not
associated with the failed thermostat, determining whether the temperature of
conditioned
air is less than a preset minimum temperature, activating an HVAC system
heating unit if
the conditioned air is less than the preset minimum temperature, operating the
heating unit
until the conditioned air is greater than a heating temperature set point,
determining, if the
conditioned air is not less than the preset minimum temperature, whether the
temperature
of conditioned air is greater than a preset maximum temperature, activating an
HVAC
system cooling unit if the conditioned air is greater than the preset maximum
temperature,
operating the cooling unit until the conditioned air is less than a cooling
temperature set
point, and returning, if the temperature of conditioned air is not greater
than the preset
maximum temperature, to the step of resetting the first timer.
[0010] In addition, a system for operating an HVAC system upon a thermostat
failure is
provided. The system includes the steps of activating an HVAC safety control
program,
resetting a first timer, determining if an amount of time in the first timer
exceeds a preset
length of time between air sampling cycles, increasing the amount of time
remaining in the
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first tinier by a first time increment if the amount of time remaining in the
first timer does
not exceed the preset length of time between air sampling cycles, activating
an HVAC
system blower when the time remaining first tinier exceeds the preset length
of time
between air sampling cycles, measuring a temperature of conditioned air on a
temperature
sensor, wherein the temperature sensor is in communication with the HVAC
safety control
program, determining whether the temperature of conditioned air is less than a
low
temperature limit set point, activating an HVAC system heating unit if the
conditioned air
is less than the low temperature limit set point, operating the heating unit
until the
conditioned air is greater than a target heating temperature set point,
determining, if the
conditioned air is not less than the low temperature limit set point, whether
the
temperature of conditioned air is greater than a high temperature limit set
point, activating
an HVAC system cooling unit if the conditioned air is greater than the high
temperature
limit set point, operating the cooling unit until the conditioned air is less
than a target
cooling temperature set point, and returning, if the temperature of
conditioned air is not
greater than the high temperature limit set point, to the step of resetting
the first timer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an isometric view of a heating, ventilation and air
conditioning (HVAC)
system with portions provided in cut-away to illustrate certain components and
which
incorporates one or more embodiments of an HVAC control program adapted to
operate
the HVAC system upon thermostat failure.
[0012] FIG. 2A is a flow diagram of a portion of an embodiment of an HVAC
control
program adapted to operate the HVAC system upon thermostat failure for use
with the
HVAC system of FIG. 1.
[0013] FIG. 2B is a flow diagram of a second portion of an embodiment of an
HVAC
control program adapted to operate the HVAC system upon thermostat failure for
use with
the HVAC system of FIG. 1.
[0014] FIG. 2C is a flow diagram of a third portion of an embodiment of an
HVAC
control program adapted to operate the HVAC system upon thermostat failure for
use with
the HVAC system of FIG. 1.
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100151 FIG. 2D is a flow diagram of a fourth portion of an embodiment of an
HVAC
control program adapted to operate the HVAC system upon thermostat failure for
use with
the HVAC system of FIG. I.
DETAILED DESCRIPTION
10016] The invention illustrated in the Figures and disclosed herein is
generally directed to
an HVAC system 100, and a safety control system 500 and associated method for
the
operation of the HVAC system 100 upon thermostat failure. For ease of
discussion and
understanding, the following detailed description will at times refer to
temperatures
measured, targeted or otherwise used in association with HVAC system 100 or
safety
control system 500 in Fahrenheit units. It should be appreciated that any
suitable
temperature measurement units, including, but not limited to, Celsius units or
Kelvin units
may be used with HVAC system 100 and/or safety control system 500.
[0017] It should also be appreciated that an "HVAC system" may include a
ducted
system, an unducted system, or any other suitable system for providing
conditioned air.
For example, an HVAC system may include, but is not limited to, a forced air
system, an
electrical base board heat system, hydronic heating or cooling, a window heat
or air
conditioning unit, or a free standing heating or air conditioning unit.
[00181 In addition, it should be appreciated that "conditioned air" may
include any
suitable treatment or adjustment to air. For example, conditioned air may
include, but is
not limited to, heated air, cooled air, cleaned air, humidified air,
dehumidified air, and/or
filtered air. A "conditioning unit" may include any device or equipment which
conditions
air. For example, a conditioning unit may include, but is not limited to, a
heat unit, a
cooling unit, an air cleaning unit, a humidifier, a dehumidifier, an air
filter, and/or any
other device which may improve or enhance indoor air quality ("IAQ").
[0019] It should be appreciated that a "thermostat" may include any device,
controller, or
control system which regulates the temperature of an environment associated
with an
HVAC system and/or provides instructions for or signals operation of the HVAC
system.
In addition a "thermostat failure" may include any mechanical failure,
electrical failure, or
any other event in which the thermostat, device, controller, or control system
ceases to
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properly operate and/or ceases to properly communicate with the HVAC system.
For
example, a "thermostat failure" may include, but is not limited to, a loss of
power to the
thermostat, a loss of the ability for the thermostat to measure temperature, a
loss of the
ability for the thermostat to accurately measure temperature, and/or a failure
of the
thermostat to interpret or understand temperature measurements.
[0020] Referring now to the Figures, FIG. 1 illustrates an example of an HVAC
system
100 which may incorporate one or more examples of embodiments of a safety
control
system 500 for the operation of the HVAC system 100 upon thermostat failure.
HVAC
system 100 may include a return duct 110 coupled to a blower 130. A
conditioning unit
120 may be coupled to return duct 110 and be provided between return duct 110
and
blower 130. For example, as shown in FIG. 1, HVAC system 100 may include an
air
cleaning unit 120. In one or more examples of embodiments, the conditioning
unit may
include any suitable device adapted to condition air, including, but not
limited to, an air
filter, an air purifier, a humidifier, a dehumidifier, or any other known or
future developed
air cleaning, filtering, purification and/or conditioning device. In one or
more examples of
embodiments, the conditioning unit may be provided at any suitable or desired
location in
association with the return duct and/or supply duct. Further, in one or more
examples of
embodiments, a plurality of conditioning units may be provided at any suitable
or desired
locations in association with the HVAC system.
[0021] Blower 130 may also be coupled to a heating unit 140 and/or a cooling
unit 150.
Heating unit 140 and/or cooling unit 150 may subsequently be coupled to a
supply duct
160. The supply duct 160 generally provides handled and/or conditioned air to
the
environment regulated by HVAC system 100. It should be appreciated that
handled air
may include, but not be limited to, air provided for ventilation, cleaned air,
or filtered air.
It should also be appreciated that conditioned air may include, but not be
limited to, air
which is heated and/or air which is cooled.
[0022] HVAC system 100 may also include a thermostat or user interface 200 and
associated control system. Thermostat 200 may be provided in the environment
regulated
by HVAC system 100. Thermostat 200 generally monitors the temperature
conditions in
the environment, may provide information regarding the HVAC system 100 to user
400,
may receive HVAC system 100 control settings entered by user 400, may store
control
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settings for HVAC system 100, and/or may execute control settings for HVAC
system
100.
[0023] Thermostat 200 may be in communication with an HVAC controller or
equipment
interface module or EIM 300. For example, thermostat 200 may include a blower
call line
230, a heating unit call line 240, and/or a cooling unit call line 250. The
blower call line
230, heating unit call line 240, and/or cooling unit call line 250 may couple
thermostat 200
with HVAC controller 300. In addition, HVAC controller 300 may be provided
near the
air handling equipment 130, 140, 150. Further, HVAC controller 300 may be in
communication with the air handling equipment 130, 140, 150. HVAC controller
300
may include a blower control line 330, a heating unit control line 340, and a
cooling unit
control line 350. The blower control line 330, heating unit control line 340,
and cooling
unit control line 350 may couple HVAC controller 300 with the respective
blower 130,
heating unit 140, and cooling unit 150. In one or more examples of
embodiments, the
blower call line, heating unit call line, cooling unit call line, blower
control line, heating
unit control line, and/or cooling unit control line may be any suitable
communication
medium to convey communication signals, including, but not limited to, wired,
wireless,
or any future developed suitable communication medium.
[0024] A temperature sensor or return air temperature sensor 360 may be in
communication with HVAC controller 300 by a temperature sensor line 370. As
illustrated in FIG. 1, temperature sensor 360 may be provided in return duct
110.
Temperature sensor 360 may measure or detect the temperature of air within or
traveling
though return duct 110. Information gathered by temperature sensor 360 may be
communicated to HVAC controller 300 through temperature sensor line 370. The
information gathered may include, but is not limited to, the temperature of
the measured
air, a resistance, and/or a voltage. In one or more examples of embodiments,
the
temperature sensor may be any suitable device for measuring temperature,
including, but
not limited to, a thermister, a resistance temperature detector, and/or a
thermocouple
temperature measurement sensor. In addition, in one or more examples of
embodiments,
the temperature sensor may be provided or placed in any desired or suitable
location for
measuring the temperature of air, including, but not limited to, the
environment regulated
by the HVAC system, the supply duct, or any location suitable to measure the
temperature
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of conditioned air selected by an HVAC system installer. Further, in one or
more
examples of embodiments, the temperature sensor may be associated with or
housed in the
thermostat. In one or more examples of embodiments, the temperature sensor
line may be
any suitable communication medium to convey communication signals, including,
but not
limited to, wired, wireless, or any future developed suitable communication
medium.
[00251 In operation and use of HVAC system 100, a blower activation signal
will be
provided to blower 130 through blower control line 330. The signal may
originate from
thermostat 200 and be carried to HVAC controller 300 by blower call line 230,
or may
originate from HVAC controller 300. Blower 130 will activate and pull return
air through
return duct 110. Return duct 110 provides air to be handled and/or conditioned
by HVAC
system 100. Return duct 110 is in communication with an air source, for
example, but not
limited to, air from the environment regulated by HVAC system 100 and/or air
from an
outside environment, such as from the outdoors. Generally, blower 130 pulls
air into
return duct 110 and subsequently through air cleaning unit 120. Blower 130 may
then
send the air through heating unit 140 and/or cooling unit 150, and into supply
duct 160.
The air is then pushed or blown by blower 130 through supply duct 160 and into
the
environment regulated by HVAC system 100. I-1VAC system 100 will continue to
handle
air until blower 130 is signaled to deactivate. These steps provide an example
of handling
or cycling air about the environment regulated by HVAC system 100.
100261 HVAC system 100 may also warm or heat the air of the environment
regulated by
HVAC system 100. In addition to the steps recited above, a heating unit
activation signal
may be provided to heating unit 140 through heating unit control line 340. The
signal may
originate from thermostat 200. For example, thermostat 200 may measure the
ambient
temperature of an environment controlled by HVAC system 100 and determine that
the
environment temperature is below a pre-defined temperature limit, and thus too
cold.
Thermostat 200 will send a heating unit activation call to HVAC control 300
through
heating unit call line 240. HVAC control 300 will subsequently transmit an
associated
heating unit activation signal to heating unit 140 through heating unit
control line 340.
Heating unit 140 will activate, increasing the temperature or warming the air
pushed
through heating unit 140 by blower 130. The warmer air will then be
distributed into the
environment regulated by HVAC system 100 via supply duct 160. HVAC system 100
will
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continue to warm or heat air until heating unit 140 is signaled to deactivate.
In one or
more examples of embodiments, the heating unit activation signal may originate
from
HVAC control 300 and be communicated to heating unit 140 through heating unit
control
line 340.
[0027] HVAC system 100 may also chill or cool the air of the environment
regulated by
HVAC system 100. In addition to the steps recited above in association with
handling or
cycling air, a cooling unit activation signal may be provided to cooling unit
150 through
cooling unit control line 350. The signal may originate from thermostat 200.
For
example, thermostat 200 may measure the ambient temperature of an environment
controlled by HVAC system 100 and determine that the environment temperature
is above
a pre-defined temperature limit, and thus too warm. Thermostat 200 will send a
cooling
unit activation call to HVAC control 300 through cooling unit call line 250.
HVAC
control 300 will subsequently transmit an associated cooling unit activation
signal to
cooling unit 150 through cooling unit control line 350. Cooling unit 150 will
activate,
decreasing the temperature or cooling the air pushed through cooling unit 150
by blower
130. The cooler air will then be distributed into the environment regulated by
HVAC
system 100 via supply duct 160. HVAC system 100 will continue to chill or cool
air until
cooling unit 150 is signaled to deactivate. In one or more examples of
embodiments, the
cooling unit activation signal may originate from HVAC control 300 and be
communicated to cooling unit 150 through cooling unit control line 350.
[00281 The foregoing presents one or more examples of embodiments of HVAC
system
100. HVAC system 100 may also include one or more embodiments of an HVAC
safety
control system or program or application 500. Safety control application 500
may
continue to operate HVAC system 100 in situations of thermostat failure. HVAC
safety
control program 500 may be provided on a machine-readable or computer-readable
medium or electronically readable storage medium which is in operable
communication
with HVAC system 100 and/or HVAC controller 300. In addition, HVAC safety
control
program 500 may reside as a program module which may be stored and/or operated
on
HVAC controller 300. The HVAC safety control program 500 may be prepared or
written
in any suitable programming language which enables communication with and/or
control
of HVAC system 100. The steps recited in association with HVAC safety control
program
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500 may reside or be stored as one or more instructions or program parameters
which may
be executable by HVAC system 100 and/or HVAC controller 300. In one or more
examples of embodiments, HVAC safety control program 500 may reside on
thermostat
200, for example on a multi-part thermostat with each part having an
independent power
source. In addition, in one or more examples of embodiments, HVAC safety
control
program 500 may reside on a controller which is independent from, but
integrated into
thermostat 200, for example as an add on component having an independent power
source
from thermostat 200. In one or more examples of embodiments, HVAC safety
control
program 500 may reside on an independent controller, device, or module which
is
independent and/or separate from thermostat 200. Such an independent
controller, device,
or module may be in communication with HVAC controller 300 and/or thermostat
200. In
one or more examples of embodiments, the electronically readable storage
medium may
include any data storage device which can store data that can be thereafter
read by an
electronic or computer system. Examples of electronically readable storage
medium may
include, but is not limited to, a computer hard drive, read-only memory, CD-
ROM, CD-R,
CD-RW, DVD, DVD-RW, magnetic tapes, Universal Serial Bus (USB) flash drive, or
any
other suitable data storage device.
[0029] Referring to FIG. 2, the respective HVAC safety control program 500
includes a
series of steps or processing instructions which are depicted in flow chart or
flow diagram
form. HVAC control program 500 may be implemented on a controller in
association
with HVAC system 100, for example, but not limited to, HVAC controller 300.
[0030] Referring to FIG. 2A, at step 502, HVAC safety control program 500
determines if
controller 300 is receiving valid communication data from thermostat 200. For
example,
program 500 may initiate and send an electronic signal or control signal or
signal to
thermostat 200. As another example, program 500 may measure the air
temperature
through temperature sensor 360, and, if the air temperature is above a preset
upper limit or
below a preset lower limit, may attempt to signal thermostat 200. If at step
502, the
determination is "yes," controller 300 is receiving valid communication data
from
thermostat 200, program 500 will repeat step 502 and continue to monitor and
determine
whether controller 300 is receiving valid communication data from thermostat
200. If the
determination is "no," controller 300 is not receiving valid communication
data from
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thermostat 200, a thermostat failure has likely occurred. Program 500 will
then move to
step 504, in which backup control is activated.
[0031] At step 504, controller 300 turns off all relays, terminating the
operation of blower
130, heating unit 140, and/or cooling unit 150. In addition, controller 300
deactivates all
equipment status LED readouts, and activates backup control.
[0032] Next, at step 506, program 500 may optionally provide notification
outside of
HVAC system 100 that a thermostat failure has occurred. For example,
notification may
include powering on a notification light at controller 300 and/or thermostat
200, initiating
an audible alert signal, sending a notification of thermostat failure to a
security service,
sending a message providing notification of thermostat failure through email
to one or
more preprogrammed email addresses, sending a text message to one or more
preprogrammed cellular telephone numbers providing notification of thermostat
failure,
and/or an making an automated telephone call to one or more preprogrammed
telephone
numbers that a thermostat failure has occurred. In addition, any of the
notifications may
also communicate that HVAC system backup control has been activated. It should
be
appreciated in one or more examples of embodiments that notification may be
made
through any suitable communication methodology.
[0033] At step 508, a timer, Timer 1, may be reset to an initial time period
value. Timer 1
represents an air sampling cycle timer or return air sampling cycle timer.
More
specifically, Timer I may represent the measured length of time between air
sampling
cycles. Timer 1 may be used to ensure a preset or predetermined amount of time
separates
air sampling iterations. As illustrated in FIG. 2A, Timer 1 may be a "count-
up" timer.
Accordingly, Timer 1 may be reset to zero at step 508. In one or more examples
of
embodiments, Timer 1 may be a "count-down" timer which is reset to a
predetermined
amount of time at step 508.
[0034] At step 510, the current time period value stored or held in Timer 1
may be
increased or incremented by a desired first time increment. A desired first
time increment
may be one second, thirty seconds, one minute, or any desired amount of second
and/or
minutes. In one or more examples of embodiments, Timer 1 may be decreased or
decremented by a desired first time increment in association with a "count-
down" timer.
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[0035] Next, at step 512, program 500 determines if the current time period
value stored
in Timer 1, and which was previously adjusted or changed at step 510, is
greater than a
first predetermined air sampling cycle time period or first time period,
Variable 1. This
determination ascertains whether adequate time has elapsed between consecutive
air
sampling cycles. It should be appreciated that Variable I may be a preset
amount of time
or a predetermined amount of time. In addition, the amount of time preset,
entered, and/or
stored as Variable 1 may be entered by the manufacturer, by an installer who
installs the
HVAC system 100 and/or program 500, or by a user 400. In one or more examples
of
embodiments, program 500 determines if Timer I is less than Variable 1 (or
less than or
equal to) in association with a "count-down" timer.
[0036] If the determination at step 512 is "no," the current time period value
stored in
Timer 1 is not greater than Variable 1 (or in the alternative is not greater
than or equal to,
or not equal to Variable 1), program 500 returns to step 510. Steps 510 and
512
subsequently repeat until the determination at step 512 is "yes." If the
determination at
step 512 is "yes," the current time value stored in Timer I is greater than
Variable 1 (or
equal to, or greater than or equal to), control program 500 moves to step 514.
In one or
more examples of embodiments in association with a "count-down" timer, the
"no"
determination occurs when Timer 1 is greater than Variable 1, while the "yes"
determination occurs when Timer 1 is less than, less than or equal to, or
equal to Variable
1.
[0037] Referring to FIG. 2B, at step 514, program 500 initiates an air
sampling cycle.
Specifically, at step 514, program 500 activates blower 130. For example,
blower 130
may be activated through blower control line 330. As another example, program
500 may
provide instructions to HVAC controller 300 to activate blower 130. Activation
of blower
130 moves air through HVAC system 100, enabling temperature sensor 360 to
accurately
measure the temperature of air in the environment regulated by HVAC system
100.
[0038] Next, at step 516, a timer, Timer 2, may be reset to an initial time
period value.
Timer 2 represents an air sampling timer or return air sampling timer. More
specifically,
Timer 2 may represent the measured length of time blower 130 may operate
before
measuring the temperature of air in the environment regulated by HVAC system
100.
Timer 2 may be used to ensure adequate air from the environment regulated by
HVAC
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system 100 cycles through HVAC system 100. As illustrated in FIG. 2B, Timer 2
may be
a "count-up" timer. Accordingly, Timer 2 may be reset to zero at step 516. In
one or
more examples of embodiments, Timer 2 may be a "count-down" timer which is
reset to a
predetermined amount of time at step 516.
[0039] At step 518, the current time period value stored or held in Timer 2
may be
increased or incremented by a desired second time increment. A desired second
time
increment may be one second, thirty seconds, one minute, or any desired amount
of
second and/or minutes. In one or more examples of embodiments, Timer 2 may be
decreased or decremented by a desired second time increment in association
with a
"count-down" timer.
[00401 Next, at step 520, a determination is made if the current time period
value stored in
Timer 2, and which was previously adjusted or changed at step 518, is greater
than a
second predetermined air sampling time period or second time period, Variable
2. This
determination ascertains whether adequate time has elapsed to ensure adequate
air from
the environment regulated by HVAC system 100 cycles through HVAC system 100
before
measuring the temperature of the air. It should be appreciated that Variable 2
may be a
preset amount of time or a predetermined amount of time. In addition, the
amount of time
preset, entered, and/or stored as Variable 2 may be entered by the
manufacturer, by an
installer who installs the HVAC system 100 and/or program 500, or by a user
400. In one
or more examples of embodiments, program 500 determines if Timer 2 is less
than
Variable 2 (or less than or equal to) in association with a "count-down"
timer.
[00411 If the determination at step 520 is "no," the current time period value
stored in
Timer 2 is not greater than Variable 2 (or in the alternative is not greater
than or equal to,
or not equal to Variable 2), program 500 returns to step 518. Steps 518 and
520
subsequently repeat until the determination at step 520 is "yes." If the
determination at
step 520 is "yes," the current time value stored in Timer 2 is greater than
Variable 2 (or
equal to, or greater than or equal to), control program 500 moves to step 522.
In one or
more examples of embodiments in association with a "count-down" timer, the
"no"
determination occurs when Timer 2 is greater than Variable 2, while the "yes"
determination occurs when Timer 2 is less than, less than or equal to, or
equal to Variable
2.
- 13 -
CA 02803344 2013-01-18
[0042] At step 522, the ambient air temperature of the air from the
environment regulated
by HVAC system 100 is determined by measuring the temperature at temperature
sensor
360. For example, in the embodiment illustrated in FIG. 1, the temperature of
the air in
return duct 110 is measured through temperature sensor 360. At step 523, the
temperature
measured at temperature sensor 360 may be stored as Variable 3.
[0043] At step 524, program 500 determines if the measured temperature stored
in
Variable 3 is less than or equal to a predetermined environment minimum
temperature or
minimum set point Variable 4. For example, the predetermined environment
minimum
temperature stored in Variable 4 may be 40 Fahrenheit. If the determination
at step 524
is "yes," the temperature stored in Variable 3 is less than or equal to the
predetermined
temperature stored in Variable 4, program 500 moves to step 560. If the
determination at
step 524 is "no," the temperature stored in Variable 3 is not less than or
equal to the
predetermined temperature stored in Variable 4, program 500 moves to step 526.
It should
be appreciated that Variable 4 may be any desired or suitable preset
temperature or
predetermined temperature. In addition, the temperature preset, entered,
and/or stored as
Variable 4 may be entered by the manufacturer, by an installer who installs
the HVAC
system 100 and/or program 500, or by a user 400.
[0044] At step 526, program 500 determines if the measured temperature stored
in
Variable 3 is greater than or equal to a predetermined environment maximum
temperature
or maximum set point, Variable 5. For example, the predetermined environment
maximum temperature stored in Variable 5 may be 100 Fahrenheit. If the
determination
at step 526 is "yes," the temperature stored in Variable 3 is greater than or
equal the
predetermined temperature stored in Variable 5, program 500 moves to step 570.
If the
determination at step 526 is "no," the temperature stored in Variable 3 is not
greater than
or equal to the predetermined temperature stored in Variable 5, program 500
moves to step
528. It should be appreciated that Variable 5 may be any desired or suitable
preset
temperature or predetermined temperature. In addition, the temperature preset,
entered,
and/or stored as Variable 5 may be entered by the manufacturer, by an
installer who
installs the HVAC system 100 and/or program 500, or by a user 400.
[0045] At step 528, HVAC blower 130 is deactivated. Program 500 then returns
to step
508. Steps 508 through 528 will subsequently repeat until a determination of
"yes" occurs
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CA 02803344 2013-01-18
at step 524, a determination of "yes' occurs at step 526, or IIVAC controller
300 regains
communication with thermostat 200. If HVAC controller 300 regains
communication
with thermostat 200 at any time, program 500 may terminate, as the thermostat
failure will
have ended. Upon termination of program 500, all HVAC system relays will be
turned
off, terminating the operation of blower 130, heating unit 140, and/or cooling
unit 150. In
addition, controller 300 deactivates all equipment status LED readouts and
deactivates
backup control program 500. Control of HVAC system 100 will subsequently be
initiated
and/or maintained by thermostat 200. In one or more examples of embodiments,
to
terminate program 500, HVAC system 100 may require some manual reset or manual
actuation by an installer, user, or repair person in order for thermostat 200
to regain
control of HVAC system 100.
100461 Referring to FIG. 2C, at step 560, which is reached following a "yes"
determination at step 524, the "heat" functionality of HVAC system 100 is
activated.
More specifically, heating unit 140 is activated. In various embodiments,
heating unit 140
may be activated by instructions provided by program 500. For example, program
500
may communicate with HVAC controller 300 to activate the "heat" of HVAC system
100.
As such, HVAC controller 300 may send a signal across heater control line 340
to activate
heating unit 140. However, in one or more examples of embodiments, any
suitable
methodology for activating the "heat" functionality of HVAC system 100 may be
utilized
or implemented.
[00471 Next at step 562, a timer, Timer 3, may be reset to an initial time
period value.
Timer 3 represents a heating unit minimum operation timer. More specifically,
Timer 3
may represent the minimum length of time heating unit 140 may operate during a
heating
cycle operated by program 500. As illustrated in FIG. 2C, Timer 3 may be a
"count-up"
timer. Accordingly, Timer 3 may be reset to zero at step 562. In one or more
examples of
embodiments, Timer 3 may be a "count-down" timer which is reset to a
predetermined
amount of time at step 562. It should be appreciated that step 562 may
coincide with step
560, or may occur immediately prior to or simultaneously with step 560 in
order to insure
the "heat" functionality of HVAC system 100 operates for the amount of time
stored in
Timer 3.
[00481 Next, at step 564, the current time period value stored or held in
Timer 3 may be
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CA 02803344 2013-01-18
increased or incremented by a desired third time increment. A desired third
time
increment may be one second, thirty seconds, one minute, or any desired amount
of
second and/or minutes. In one or more examples of embodiments, Timer 3 may be
decreased or decremented by a desired third time increment in association with
a "count-
down" timer,
[0049] Next, at step 566, a determination is made if the current time period
value stored in
Timer 3, and which was previously adjusted or changed at step 564, is greater
than or
equal to a predetermined heating equipment minimum on time or minimum run time
or
sixth time period, Variable 6. This determination ascertains whether adequate
time has
elapsed to ensure a minimum amount of heating for the environment regulated by
HVAC
system 100. In addition, the determination may ensure the HVAC system 100
heating unit
140 operates or runs for a minimum amount of time. It should be appreciated
that
Variable 6 may be a preset amount of time or a predetermined amount of time.
In
addition, the amount of time preset, entered, and/or stored as Variable 6 may
be entered by
the manufacturer, by an installer who installs the HVAC system 100 and/or
program 500,
or by a user 400. In one or more examples of embodiments, program 500
determines if
Timer 3 is less than Variable 6 (or less than or equal to) in association with
a "count-
down" timer.
100501 If the determination at step 566 is "no," the current time period value
stored in
Timer 3 is not greater than Variable 6 (or in the alternative is not greater
than or equal to,
or not equal to Variable 6), program 500 returns to step 564. Steps 564 and
566
subsequently repeat until the determination at step 566 is "yes." If the
determination at
step 566 is "yes," the current time value stored in Timer 3 is greater than or
equal to
Variable 6 (or in various embodiments equal to, or greater than), control
program 500
moves to step 568. In one or more examples of embodiments in association with
a "count-
down" timer, the "no" determination occurs when Timer 3 is greater than
Variable 6,
while the "yes" determination occurs when Timer 3 is less than, less than or
equal to, or
equal to Variable 6.
[00511 At step 568, the ambient air temperature of the air from the
environment regulated
by HVAC system 100 is determined by measuring the temperature at temperature
sensor
360. For example, in the embodiment illustrated in FIG. 1, the temperature of
the air in
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CA 02803344 2013-01-18
return duct 110 is measured through temperature sensor 360. At step 570, the
temperature
measured at temperature sensor 360 may be stored, for example again as
Variable 3. In
various embodiments, the temperature measured at temperature sensor 360 may be
stored
in a separate, unique variable, for example as Variable 10.
[0052) At step 572, a determination whether the measured temperature stored in
Variable
3 is greater than or equal to a predetermined heating temperature set point or
heating set
point Variable 7. For example, the predetermined heating temperature set point
stored in
Variable 7 may be 43 Fahrenheit. If the determination at step 572 is "no,"
the
temperature stored in Variable 3 is not greater than or equal to the
predetermined heating
temperature set point stored in Variable 7, program 500 returns to step 568.
Steps 568,
570, and 572 subsequently repeat and the HVAC system 100, blower 130 and
heating unit
140 continue to operate until the determination at step 572 is "yes." If the
determination is
"yes," the temperature stored in Variable 3 is greater than or equal to the
predetermined
heating temperature set point stored in Variable 7, program 500 proceeds to
step 574, It
should be appreciated that Variable 7 may be any desired or suitable preset
temperature or
predetermined temperature. In addition, the temperature preset, entered,
and/or stored as
Variable 7 may be entered by the manufacturer, by an installer who installs
the HVAC
system 100 and/or program 500, or by a user 400.
[0053] At step 574, the blower 130 and heating unit 140 are deactivated. Next
program
500 will return to step 508. Steps 508 through 528 will subsequently repeat
until a
determination of "yes" occurs at step 524, a determination of "yes' occurs at
step 526, or
HVAC controller 300 regains communication with thermostat 200. If HVAC
controller
300 regains communication with thermostat 200 at any time, program 500 may
terminate,
as the thermostat failure will have ended. Upon termination of program 500,
all I-1VAC
system relays will be turned off, terminating the operation of blower 130,
heating unit 140,
and/or cooling unit 150. In addition, controller 300 deactivates all equipment
status LED
readouts and deactivates backup control program 500. Control of HVAC system
100 will
subsequently be initiated and/or maintained by thermostat 200. In one or more
examples
of embodiments, to terminate program 500, HVAC system 100 may require some
manual
reset or manual actuation by an installer, user, or repair person in order for
thermostat 200
to regain control of HVAC system 100.
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CA 02803344 2013-01-18
[0054] Referring to FIG. 2D, at step 580, which is reached following a "yes"
determination at step 526, the "cooling" functionality of HVAC system 100 is
activated.
More specifically, cooling unit 150 is activated. In various embodiments,
cooling unit 150
may be activated by instructions provided by program 500. For example, program
500
may communicate with HVAC controller 300 to activate the "cooling" of HVAC
system
100. As such, HVAC controller 300 may send a signal across cooling control
line 350 to
activate cooling unit 150. However, in one or more examples of embodiments,
any
suitable methodology for activating the "cooling" functionality of HVAC system
100 may
be utilized or implemented.
[0055] Next at step 582, a timer, Timer 4, may be reset to an initial time
period value.
Timer 4 represents a cooling unit minimum operation timer. More specifically,
Timer 4
may represent the minimum length of time cooling unit 150 may operate during a
cooling
cycle operated by program 500. As illustrated in FIG. 2D, Timer 4 may be a
"count-up"
timer. Accordingly, Timer 4 may be reset to zero at step 582. In one or more
examples of
embodiments, Timer 4 may be a "count-down" timer which is reset to a
predetermined
amount of time at step 582. It should be appreciated that step 582 may
coincide with step
580, or may occur immediately prior to or simultaneously with step 580 in
order to insure
the "cooling" functionality of HVAC system 100 operates for the amount of time
stored in
Timer 4.
[0056] Next, at step 584, the current time period value stored or held in
Timer 4 may be
increased or incremented by a desired fourth time increment. A desired fourth
time
increment may be one second, thirty seconds, one minute, or any desired amount
of
second and/or minutes. In one or more examples of embodiments, Timer 4 may be
decreased or decremented by a desired fourth time increment in association
with a "count-
down" timer.
[0057] Next, at step 586, a determination is made if the current time period
value stored in
Timer 4, and which was previously adjusted or changed at step 584, is greater
than or
equal to a predetermined cooling equipment minimum on time or minimum run time
or
eighth time period, Variable 8. This determination ascertains whether adequate
time has
elapsed to ensure a minimum amount of cooling for the environment regulated by
HVAC
system 100. In addition, the determination may ensure the HVAC system 100
cooling unit
- 18 -
CA 02803344 2013-01-18
150 operates or runs for a minimum amount of time. It should be appreciated
that
Variable 8 may be a preset amount of time or a predetermined amount of time.
In
addition, the amount of time preset, entered, and/or stored as Variable 8 may
be entered by
the manufacturer, by an installer who installs the HVAC system 100 and/or
program 500,
or by a user 400. In one or more examples of embodiments, program 500
determines if
Timer 4 is less than Variable 8 (or less than or equal to) in association with
a "count-
down" timer.
[00581 If the determination at step 586 is "no," the current time period value
stored in
Timer 4 is not greater than Variable 8 (or in the alternative is not greater
than or equal to,
or not equal to Variable 8), program 500 returns to step 584. Steps 584 and
586
subsequently repeat until the determination at step 586 is "yes." If the
determination at
step 586 is "yes," the current time value stored in Timer 4 is greater than or
equal to
Variable 8 (or in various embodiments equal to, or greater than), control
program 500
moves to step 588. In one or more examples of embodiments in association with
a "count-
down" timer, the "no" determination occurs when Timer 4 is greater than
Variable 8,
while the "yes" determination occurs when Timer 4 is less than, less than or
equal to, or
equal to Variable 8.
100591 At step 588, the ambient air temperature of the air from the
environment regulated
by HVAC system 100 is determined by measuring the temperature at temperature
sensor
360. For example, in the embodiment illustrated in FIG. 1, the temperature of
the air in
return duct 110 is measured through temperature sensor 360. At step 590, the
temperature
measured at temperature sensor 360 may be stored, for example again as
Variable 3. In
various embodiments, the temperature measured at temperature sensor 360 may be
stored
in a separate, unique variable, for example as Variable 11.
[0060] At step 592, a determination whether the measured temperature stored in
Variable
3 is less than or equal to a predetermined cooling temperature set point or
cooling set point
Variable 9. For example, the predetermined heating temperature set point
stored in
Variable 9 may be 97 Fahrenheit. If the determination at step 592 is "no,"
the
temperature stored in Variable 3 is not less than or equal to the
predetermined cooling
temperature set point stored in Variable 9, program 500 returns to step 588.
Steps 588,
590, and 592 subsequently repeat and the HVAC system 100, blower 130 and
cooling unit
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CA 02803344 2013-01-18
150 continue to operate until the determination at step 592 is "yes." If the
determination is
"yes," the temperature stored in Variable 3 is less than or equal to the
predetermined
cooling temperature set point stored in Variable 9, program 500 proceeds to
step 594. It
should be appreciated that Variable 9 may be any desired or suitable preset
temperature or
predetermined temperature. In addition, the temperature preset, entered,
and/or stored as
Variable 9 may be entered by the manufacturer, by an installer who installs
the HVAC
system 100 and/or program 500, or by a user 400.
(0061] At step 594, the blower 130 and cooling unit 150 are deactivated. Next,
program
500 will return to step 508. Steps 508 through 528 will subsequently repeat
until a
determination of "yes" occurs at step 524, a determination of "yes' occurs at
step 526, or
HVAC controller 300 regains communication with thermostat 200. If HVAC
controller
300 regains communication with thermostat 200 at any time, program 500 may
terminate,
as the thermostat failure will have ended. Upon termination of program 500,
all HVAC
system relays will be turned off, terminating the operation of blower 130,
heating unit 140,
and/or cooling unit 150. In addition, controller 300 deactivates all equipment
status LED
readouts and deactivates backup control program 500. Control of HVAC system
100 will
subsequently be initiated and/or maintained by thermostat 200. In one or more
examples
of embodiments, to terminate program 500, HVAC system 100 may require some
manual
reset or manual actuation by an installer, user, or repair person in order for
thermostat 200
to regain control of HVAC system 100.
10062] It should be appreciated that in one or more examples of embodiments of
safety
control program 500, the first time period (Variable 1), the second time
period (Variable
2), predetermined environment minimum temperature (Variable 4), predetermined
environment maximum temperature (Variable 5), minimum heating equipment on
time
(Variable 6), minimum cooling equipment on time (Variable 8), heating
temperature set
point (Variable 7), cooling temperature set point (Variable 9), and/or other
timers or target
temperatures may be any predetermined value which may be set by the
manufacturer, user,
or HVAC system installer. In addition, certain Variables may be preset or
entered for
certain desired operational parameters, for example to intentionally add some
amount of
hysteresis into the control program 500. Further, in one or more examples of
embodiments of safety control program 500, program 500 and/or HVAC controller
300
- 20 -
CA 02803344 2013-01-18
may be implemented on a thermostat which may have separate and dedicated
circuitry and
power to enable operation of program 500 and/or controller 300 in the
occurrence of a
thermostat failure.
100631 In operation and use of control program 500, an HVAC system 100 will
typically
be in communication with a thermostat 200. Thermostat 200 will provide
operating
instructions to HVAC system 100 and/or HVAC controller 300. Should thermostat
200
cease to properly operate or function, control program 500 will initiate and
assume control
of operation of HVAC system 100. Control program 500 will make a determination
whether HVAC system 100 is receiving communication data or signals, valid
communication data or signals, or any data or signals from thermostat 200 (at
step 502 of
FIG. 2A). If thermostat 200 is not properly functioning, backup control of
HVAC system
100 will be activated and all HVAC system components will be deactivated or
powered
down (at step 504 of FIG. 2A). A notification of thermostat failure may also
be initiated
(at step 506 of FIG. 2A). An air sampling cycle timer is then reset (at step
508 of FIG.
2A). The air sampling cycle timer will then be initiated to track and store in
Timer 1 the
amount of time between cycles of air sampling (at steps 510, 512 of FIG. 2A).
When the
elapsed amount of time between cycles of air sampling (Timer 1) exceeds a
preset amount
of time between air sampling cycles (Variable 1) (at step 512 of FIG. 2A), an
air sampling
cycle will be initiated (at steps 514-528 of FIG. 2B).
[0064] During an air sampling cycle, air may be cycled through the HVAC system
100 for
a period of time. Specifically, HVAC blower 130 may be activated (at step 514
of FIG.
23). Simultaneously, an air sampling timer is then reset (at step 516 of FIG.
2B). The air
sampling timer will then be initiated to track and store in Timer 2 the amount
of time of
the air sampling cycle (at steps 518, 520 of FIG. 2B). The air sampling timer
allows for
air to be blown through HVAC system 100 for a period of time (i.e. the amount
of time
elapsed in Timer 2). When the elapsed amount of time of the air sampling timer
(Timer 2)
exceeds a preset amount of time for an air sampling cycle (Variable 2) (at
step 520 of FIG.
2B), the temperature of the air cycled through the HVAC system 100 will be
measured
and stored (in Variable 3) (at steps 522, 523 of FIG. 2B), The stored
temperature of the air
cycled through the HVAC system 100 is then analyzed (at steps 524, 526 of FIG.
28). If
the stored temperature (Variable 3) is below or equal to (or alternatively
below) a low
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CA 02803344 2013-01-18
temperature limit set point (Variable 4), a heating cycle will be initiated
(at step 524 of
FIG. 2B). If the stored temperature (Variable 3) is not below or equal to (or
alternatively
not below) a low temperature limit set point (Variable 4), the stored
temperature will be
additionally analyzed (at step 526 of FIG. 2B). If the stored temperature
(Variable 3) is
above or equal to (or alternatively above) a high temperature limit set point
(Variable 5), a
cooling cycle will be initiated (at step 526 of FIG. 2B). If the stored
temperature (Variable
3) is not above or equal to (or alternatively not above) a low temperature
limit set point
(Variable 4), the HVAC system blower is deactivated (at step 528 of FIG. 2B).
The
system will then initiate another time period between air sample cycles by
resetting the air
sampling cycle timer (Timer 1) (repeating steps 508-512 of FIG. 2A). After
completion of
another time period between air sample cycles (steps 508-512 of FIG. 2A),
another air
sampling cycle will be initiated (steps 514-528 of FIG. 2B). This process will
repeat until
a heating cycle is initiated (steps 560-574 of FIG. 2C), a cooling cycle is
initiated (steps
580-594 of FIG. 2D), or the control program 500 terminates.
100651 If a heating cycle is initiated (steps 560-574 of FIG. 2C), the heating
unit 140 of
HVAC system 100 is activated (at step 560 of FIG. 2C). Simultaneously, a
heating unit
minimum operation timer is reset (at step 562 of FIG. 2C). The heating unit
minimum
operation timer will then be initiated to track and store in Timer 3 the
amount of time the
heating unit operates (at steps 564, 566 of FIG. 2C). The heating unit minimum
operation
timer represents the minimum length of time heating unit 140 may operate
during a
heating cycle. When the elapsed amount of time of the heating unit minimum
operation
timer (Timer 3) exceeds (or is greater than or equal to) a preset heating unit
minimum run
time (Variable 6) (at step 566 of FIG. 2C), the temperature of the air cycled
through the
HVAC system 100 will be measured and stored (in Variable 3) (at steps 568, 570
of FIG.
2C). The stored temperature of the heated air cycled through the HVAC system
100 and
environment is then analyzed (at step 572 of FIG. 2C). If the stored
temperature (Variable
3) is not greater than or equal to (or alternatively not greater than) a
heating temperature
set point (Variable 7) (at step 572 of FIG. 2C), the heating cycle will
continue and
additional temperatures of the air will be taken and analyzed (repeat steps
568-572 of FIG.
2C). If the stored temperature (Variable 3) is greater than or equal to (or
alternatively
greater than) a heating temperature set point (Variable 7), the heating cycle
will be
- 22 -
CA 02803344 2013-01-18
terminated, with the heating unit 140 and HVAC blower 130 being deactivated
(at step
574 of FIG. 2C), The system will then initiate another time period between air
sample
cycles by resetting the air sampling cycle timer (Timer 1) (repeating steps
508-512 of FIG.
2A). After completion of another time period between air sample cycles (steps
508-512 of
FIG. 2A), another air sampling cycle will be initiated (steps 514-528 of FIG.
2B). This
process will repeat until a heating cycle is initiated (steps 560-574 of FIG.
2C), a cooling
cycle is initiated (steps 580-594 of FIG. 2D), or the control program 500
terminates.
(00661 If a cooling cycle is initiated (steps 580-594 of FIG. 2D), the cooling
unit 150 of
FIVAC system 100 is activated (at step 580 of FIG. 2D). Simultaneously, a
cooling unit
minimum operation timer is reset (at step 582 of FIG. 2D). The cooling unit
minimum
operation timer will then be initiated to track and store in Timer 4 the
amount of time the
cooling unit operates (at steps 584, 586 of FIG. 2D). The cooling unit minimum
operation
timer represents the minimum length of time cooling unit 150 may operate
during a
cooling cycle. When the elapsed amount of time of the cooling unit minimum
operation
timer (Timer 4) exceeds (or is greater than or equal to) a preset cooling unit
minimum run
time (Variable 8) (at step 586 of FIG. 2D), the temperature of the air cycled
through the
HVAC system 100 will be measured and stored (in Variable 3) (at steps 588, 590
of FIG.
2D). The stored temperature of the cooled air cycled through the HVAC system
100 and
environment is then analyzed (at step 592 of FIG. 2D). If the stored
temperature (Variable
3) is not less than or equal to (or alternatively not less than) a cooling
temperature set point
(Variable 9) (at step 592 of FIG. 2D), the cooling cycle will continue and
additional
temperatures of the air will be taken and analyzed (repeat steps 588-592 of
FIG. 2D). If
the stored temperature (Variable 3) is less than or equal to (or alternatively
less than) a
cooling temperature set point (Variable 9), the cooling cycle will be
terminated, with the
cooling unit 150 and HVAC blower 130 being deactivated (at step 594 of FIG.
2D). The
system will then initiate another time period between air sample cycles by
resetting the air
sampling cycle timer (Timer 1) (repeating steps 508-512 of FIG. 2A). After
completion of
another time period between air sample cycles (steps 508-512 of FIG. 2A),
another air
sampling cycle will be initiated (steps 514-528 of FIG. 2B). This process will
repeat until
a heating cycle is initiated (steps 560-574 of FIG. 2C), a cooling cycle is
initiated (steps
580-594 of FIG. 2D), or the control program 500 terminates.
- 23 -
CA 02803344 2013-01-18
[0067] To further illustrate operation and use of control program 500, the
following
provides an example of certain operational scenarios using certain system
conditions. The
scenarios and associated system conditions are provided for example only, and
are not
meant to be limiting in any way. Any number or combination of scenarios or
system
conditions may be realized in association with an HVAC system 100 and/or
environment
regulated by an HVAC system 100.
[0068] As an example of a thermostat 200 failure scenario, the system may have
the
following hypothetical system conditions: all timers will be "count-up"
timers, the first,
second, third, and fourth time increments may all be 1 second (one second),
the preset
amount of time between air sampling cycles (Variable 1) may be 30 minutes
(thirty
minutes), the present amount of time for an air sampling cycle (Variable 2)
may be 3
minutes (three minutes), the low temperature limit set point (Variable 4) may
be 40 F
(forty degrees Fahrenheit), the high temperature limit set point (Variable 5)
may be 100 F
(one hundred degrees Fahrenheit), the heating unit minimum run time (Variable
6) may be
2 minutes (two minutes), the heating temperature set point (Variable 7) may be
43 F
(forty-three degrees Fahrenheit), the cooling unit minimum run time (Variable
8) may be 2
minutes (two minutes), and the cooling temperature set point (Variable 9) may
be 97 F
(ninety-seven degrees Fahrenheit).
[0069] Control program 500 may begin by making a determination whether HVAC
system 100 is receiving communication data or signals, valid communication
data or
signals, or any data or signals from thermostat 200 (at step 502 of FIG. 2A).
If it is
determined that thermostat 200 is not properly functioning, backup control of
HVAC
system 100 will be activated and all HVAC system components will be
deactivated or
powered down (at step 504 of FIG. 2A). A notification of thermostat failure
may also be
initiated (at step 506 of FIG. 2A). Air sampling cycle timer (Timer 1) is then
reset to zero
(at step 508 of FIG. 2A). Timer 1 will measure the elapsed amount of time
between cycles
of air sampling by adding one second to Timer 1 (at step 510 of FIG. 2A).
Timer 1 will
continue to add one second until Timer 1 exceeds the preset amount of time
between air
sampling cycles (repeat steps 510, 512 of FIG. 2A). When it is determined that
the
elapsed amount of time in Timer 1 exceeds the preset amount of time between
air
sampling cycles, or "Timer 1 is > thirty minutes" (at step 512 of FIG. 2A), an
air sampling
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CA 02803344 2013-01-18
cycle will be initiated (at steps 514-528 of FIG. 2B).
[00701 During an air sampling cycle, air may be cycled through the HVAC system
100 for
a period of time. Specifically, HVAC blower 130 may be activated (at step 514
of FIG.
2B). Simultaneously, air sampling timer (Timer 2) is reset to zero (at step
516 of FIG.
2B). Timer 2 will measure the elapsed amount of time for air to be blown
through HVAC
system 100 by adding one second to Timer 2 (at steps 518, 520 of FIG. 2B).
Timer 2 will
continue to add one second until Timer 2 exceeds the preset amount of time for
an air
sampling cycle (repeat steps 518, 520 of FIG. 2B). When it is determined that
the elapsed
amount of time in Timer 2 exceeds the preset amount of time for an air
sampling cycle, or
"Timer 2 is > three minutes" (at step 520 of FIG. 2B), the temperature of the
air cycled
through the HVAC system 100 will be measured and stored (in Variable 3) (at
steps 522,
523 of FIG. 2B).
The stored temperature of the cycled air is then analyzed (at steps 524, 526
of FIG. 2B). If
the measured air temperature (Variable 3) is below or equal to (or
alternatively below) the
low temperature limit set point of 40 F (forty degrees Fahrenheit), or "Air
Temperature is
<400 F," a heating cycle will be initiated (at step 524 of FIG. 2B). If the
measured air
temperature (Variable 3) is not below or equal to (or alternatively not below)
a low
temperature limit set point, or "Air Temperature is not < 40 F," the measured
air
temperature will be additionally analyzed (at step 526 of FIG. 2B). If the
measured air
temperature (Variable 3) is above or equal to (or alternatively above) the
high temperature
limit set point of 1000 F (one hundred degrees Fahrenheit), or "Air
Temperature is > 100
F," a cooling cycle will be initiated (at step 526 of FIG. 2B). If the
measured air
temperature (Variable 3) is not above or equal to (or alternatively not above)
a low
temperature limit set point, or "Air Temperature is not > 100 F," the HVAC
system
blower is deactivated (at step 528 of FIG. 2B). The system will then initiate
another time
period between air sample cycles (by repeating steps 508-512 of FIG. 2A).
These
processes will repeat until a heating cycle is initiated (steps 560-574 of
FIG. 2C), a cooling
cycle is initiated (steps 580-594 of FIG. 2D), or the control program 500
terminates.
[0071] If a heating cycle is initiated (steps 560-574 of FIG. 2C), the heating
unit 140 of
HVAC system 100 is activated (at step 560 of FIG. 2C). Simultaneously, the
heating unit
minimum operation timer is reset to zero (at step 562 of FIG. 2C). The heating
unit
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minimum operation timer will then be initiated, and Timer 3 will measure the
elapsed
amount of time of heating unit operation by adding one second to Timer 3 (at
steps 564,
566 of FIG. 2C). Timer 3 will continue to add one second until Timer 3 exceeds
(or is
greater than or equal to) the preset heating unit minimum run time of two
minutes, or
"Timer 3 is > two minutes" (at step 566 of FIG. 2C). The temperature of the
heated air
cycled through the HVAC system 100 will be measured and stored (in Variable 3)
(at
steps 568, 570 of FIG. 2C), and analyzed (at step 572 of FIG. 2C). If the
stored
temperature (Variable 3) is not greater than or equal to (or alternatively not
greater than)
the heating temperature set point of 43 F (forty-three degrees Fahrenheit),
or "Air
Temperature is not > 43 F" (at step 572 of FIG. 2C), the heating cycle will
continue and
additional temperatures of the air will be taken and analyzed (repeat steps
568-572 of FIG.
2C). If the stored temperature (Variable 3) is greater than or equal to (or
alternatively
greater than) the heating temperature set point of 43 F (forty-three degrees
Fahrenheit), or
"Air Temperature is > 43 F" (at step 572 of FIG. 2C), the heating cycle will
be
terminated, with the heating unit 140 and HVAC blower 130 being deactivated
(at step
574 of FIG. 2C). The system will then initiate another time period between air
sample
cycles (by repeating steps 508-512 of FIG. 2A). These processes will repeat
until a
heating cycle is initiated (steps 560-574 of FIG. 2C), a cooling cycle is
initiated (steps
580-594 of FIG. 2D), or the control program 500 terminates.
[00721 If a cooling cycle is initiated (steps 580-594 of FIG. 2D), the cooling
unit 150 of
HVAC system 100 is activated (at step 580 of FIG. 2D). Simultaneously, a
cooling unit
minimum operation timer is reset to zero (at step 582 of FIG. 2D). The cooling
unit
minimum operation timer will then be initiated, and Timer 4 measure the
elapsed amount
of time of cooling unit operation by adding one second to Timer 4 (at steps
584, 586 of
FIG. 2D). Timer 4 will continue to add one second until Timer 4 exceeds (or is
greater
than or equal to) the preset cooling unit minimum run time of two minutes, or
"Timer 4 is
> two minutes" (at step 586 of FIG. 2D). The temperature of the cooled air
cycled through
the HVAC system 100 will be measured and stored (in Variable 3) (at steps 588,
590 of
FIG. 2D), and analyzed (at step 592 of FIG. 2D). If the stored temperature
(Variable 3) is
not less than or equal to (or alternatively not less than) a cooling
temperature set point of
97 F (ninety-seven degrees Fahrenheit), or "Air Temperature is not < 97 F"
(at step 592
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CA 02803344 2014-09-19
of FIG. 2D), the cooling cycle will continue and additional temperatures of
the air will be
taken and analyzed (repeat steps 588-592 of FIG. 2D). If the stored
temperature (Variable
3) is less than or equal to (or alternatively less than) the cooling
temperature set point of
97 F (ninety-seven degrees Fahrenheit), or "Air Temperature is < 97 F" (at
step 592 of
FIG. 2D), the cooling cycle will be terminated, with the cooling unit 150 and
HVAC
blower 130 being deactivated (at step 594 of FIG. 2D). The system will then
initiate
another time period between air sample cycles (by repeating steps 508-512 of
FIG. 2A).
These processes will repeat until a heating cycle is initiated (steps 560-574
of FIG. 2C), a
cooling cycle is initiated (steps 580-594 of FIG. 2D), or the control program
500
terminates.
[0073] The foregoing embodiments of the HVAC system and HVAC safety control
program provide advantages over currently available devices. The HVAC safety
control
program provides protection for HVAC systems, and the structural components of
the
building which houses the HVAC systems should an associated thermostat fail.
This
includes, but is not limited to mechanical failure, electrical failure, or
failure causing
"runaway" HVAC system operation. The HVAC safety control program will
advantageously take over and maintain operation of the HVAC system when a
thermostat
fails. In addition, the HVAC safety control program also provides notice of a
thermostat
failure. For example, an home owner who is not home at the time of the failure
will
become aware of the failure, aware of activation of the HVAC safety control
program, and
can react accordingly to resolve the failure. These and other advantages may
be realized
from one or more embodiments of the HVAC system and HVAC safety control
program
disclosed herein.
[0074] Although various representative embodiments of this invention have been
described above with a certain degree of particularity, those skilled in the
art could make
numerous alterations to the disclosed embodiments. Joinder references (e.g.,
attached,
coupled, connected) are to be construed broadly and may include intermediate
members
between a connection of elements and relative movement between elements. As
such,
joinder references do not necessarily infer that two elements are directly
connected and in
fixed relation to each other. In some instances, in
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CA 02803344 2014-09-19
=
methodologies directly or indirectly set forth herein, various steps and
operations are
described in one possible order of operation, but those skilled in the art
will recognize that
steps and operations may be rearranged, replaced, or eliminated. It is
intended that all
matter contained in the above description or shown in the accompanying
drawings shall be
interpreted as illustrative only and not limiting. Changes in detail or
structure may be
made.
[0075] Although various representative examples of embodiments of this
invention have
been described above with a certain degree of particularity, those skilled in
the art could
make numerous alterations to the disclosed embodiments without departing from
the
scope of the inventive subject matter set forth in the specification and
claims. In some
instances, in methodologies directly or indirectly set forth herein, various
steps and
operations are described in one possible order of operation, but those skilled
in the art will
recognize that steps and operations may be rearranged, replaced, or eliminated
without
necessarily departing from the scope of the present invention. It is intended
that all matter
contained in the above description or shown in the accompanying drawings shall
be
interpreted as illustrative only and not limiting. Changes in detail or
structure may be
made without departing from the invention as apparent from a construction of
the
specification as a whole.
[0076] Moreover, some portions of the detailed descriptions herein are
presented in terms
of procedures, steps, logic blocks, processing, and other symbolic
representations of
operations on data bits that can be performed on computer memory. These
descriptions
and representations are the means used by those skilled in the data processing
arts to most
effectively convey the substance of their work to others skilled in the art. A
procedure,
computer executed step, logic block, process, etc., is here, and generally,
conceived to be a
self-consistent sequence of steps or instructions leading to a desired result.
The steps are
those requiring physical manipulations of physical quantities. Usually, though
not
necessarily, these quantities take the form of electrical or magnetic signals
capable of
being stored, transferred, combined, compared, and otherwise manipulated in a
computer
system. It should be borne in mind, however, that all of these and similar
terms are to be
associated with the appropriate physical quantities and are merely convenient
labels
applied to these quantities. Unless specifically stated otherwise as apparent
from the
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CA 02803344 2013-01-18
discussions herein, it is appreciated that throughout the present invention,
discussions
utilizing terms such as "receiving," "sending," "generating," "reading,"
"invoking,"
"selecting," and the like, refer to the action and processes of a computer
system, or similar
electronic computing device, including an embedded system, that manipulates
and
transforms data represented as physical (electronic) quantities within the
computer system.
[0077] Although the present invention has been described with reference to
particular
embodiments, persons skilled in the art will recognize that changes may be
made in form
and detail without departing from the spirit and scope of the invention.
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