Patent Grant
7464561
This invention relates to air conditioning and/or heat pump systems, and in particular to a unitary control for operating an air conditioning and/or heat pump system in response to signals received from a thermostat.
An air conditioning and/or heat pump system typically includes a compressor and condenser fan that are turned on and off by contactors in response to signals from a thermostat. These contactors are relatively expensive, and provide no other functionality except connecting and disconnecting the compressor motor and the condenser fan motor to electric power.
The present invention relates generally to a unitary control for air conditioning and/or heat pumps, to a combination of an air conditioning and/or heat pump system with a unitary control, to a climate control system including a thermostat, an air conditioning and/or heat pump, and a unitary control for operating the compressor and condenser fan motors, and to methods of operating the compressor and condenser fan motor.
Generally a unitary control in accordance with embodiments of this invention is adapted to receive signals from a thermostat, and operate at least the compressor motor and condenser fan motor of an air conditioning and/or heat pump system. In one preferred embodiment the unitary control comprises a circuit board; a microprocessor on the circuit board; a first relay on the circuit board operable by the microprocessor, to connect a fan connected thereto to line voltage, and having first and second contacts at least one of which is connected to the microprocessor; and a second relay on the circuit board operable by the microprocessor, to connect a compressor connected thereto to line voltage, and having first and second contacts at least one of which is connected to the microprocessor.
Generally, an air conditioning and/or heat pump and unitary control in accordance with embodiments of this invention comprises a motor driven compressor and a motor driven condenser fan, and a unitary control adapted to receive signals from a thermostat and operate at least the compressor motor and condenser fan motor. In one preferred embodiment the unitary control comprises a circuit board; a microprocessor on the circuit board; a first relay on the circuit board operable by the microprocessor, to connect a fan connected thereto to line voltage, and having first and second contacts at least one of which is connected to the microprocessor; a second relay on the circuit board operable by the microprocessor, to connect a compressor connected thereto to line voltage, and having first and second contacts at least one of which is connected to the microprocessor.
Generally, a climate control system in accordance with the present invention comprises a thermostat, an air conditioning and/or heat pump and unitary control in accordance with embodiments of this invention comprises a motor driven compressor and a motor driven condenser fan, and a unitary control adapted to receive signals from a thermostat and operate at least the compressor motor and condenser fan motor. In one preferred embodiment the unitary control comprises a circuit board; a microprocessor on the circuit board; a first relay on the circuit board operable by the microprocessor, to connect a fan connected thereto to line voltage, and having first and second contacts at least one of which is connected to the microprocessor; and a second relay on the circuit board operable by the microprocessor, to connect a compressor connected thereto to line voltage, and having first and second contacts at least one of which is connected to the microprocessor.
Generally, the method of operating an air conditioning and/or heat pump system in accordance with embodiments of this invention comprises selectively connecting the compressor motor and the condenser fan motor to electric current in response to signals from a thermostat. In one preferred embodiment the method comprises operating at least the condenser fan motor and compressor motor with relays on a circuit board with a microprocessor that controls the relays in response to a thermostat.
The unitary control used in the various aspects of this invention replaces prior electromechanical contactors, and provides reliable operation of at least the compressor motor and condenser fan motor in an air conditioning and/or heat pump system. In some embodiments, the microprocessor can operate a two stage air conditioning and/or heat pump system in response to a conventional signal stage thermostat. In other embodiments, the unitary control can automatically adjust the operation of the relays employed to prolong their life. In still other embodiments the unitary control can sense and respond to possible problems with the compressor, compressor motor, and/or condenser fan motor based on the sensed electric current provided to these components. In still other embodiments, the unitary control can automatically adjust the operation of the compressor, compressor motor, and/or condenser fan motor based sensed conditions, such as refrigerant temperature, or pressure, or ambient temperature. In additional the unitary control can be provided with communications capability to provide system information back to the thermostat, or on the control itself for service personnel.
These and other features and advantages will be in part apparent, and in part pointed out hereinafter.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
A first embodiment of unitary control in accordance with the principles of this invention, adapted for use with a basic air conditioning system, is indicated as 100 in
The unitary controller 100 also has a power bus 116 with terminals 118, 120 and 122 for connecting L2 and L1 and COM from a 220 VAC power source 26.
The unitary controller 100 also has a connector block 130 with two terminals 132 and 134 for connecting to a condenser fan 30; a connector block 136 with three terminals 138, 140 and 142 for connecting to common, run, and start leads of a compressor motor 32; and a connector block 144 with two terminals 146 and 148 for connection to a start capacitor 34.
As shown in
A condenser fan relay 190 is connected to microprocessor 184 via connection 192. The relay may be a A22500P2 latching relay manufactured by American Zettler. The relay 190 has first and second contacts 194 and 196, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 196 of which is in communication with the microprocessor. As shown in
A compressor motor relay 202 is connected to microprocessor 184 via connection 204. The relay 202 may be a A22500P2 latching relay manufactured by American Zettler. The relay 202 has first and second contacts 206 and 208, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 208 of which is in communication with the microprocessor. As shown in
A current transformer 222, connected to the microprocessor 184 via connection 224, is on a line between terminal 118 of connector block 116 (which is connected to line L2 of 240 VAC source 26) and terminal 138 of connector block 136, for electrical connection to the common lead of the compressor motor 32.
The current transformers 198, 210, 218, and 222 may be TX-P095800C010 current transformers manufactured by ATR Manufacturing LTD.
In operation, when the temperature in the space monitored by the thermostat 22 rises above the set point temperature of the thermostat, the thermostat sends a signal to the microprocessor 184. The microprocessor 184 operates relay 190 via connection 192 to connect fan motor 30 on terminals 132 and 134 to line voltage. Because the relay 190 is on the same board as the microprocessor 184, the contacts 194 and 196 of the relay can be connected to the microprocessor, so that the microprocessor can determine when the relay 190 is open and when it is closed.
After the microprocessor opens or closes the relay 190, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 194 and 196. Thus when the microprocessor sends a signal to close the relay 190, and does not detect line voltage or current on contact 196, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 190, and still detects line voltage or current on contact 196, the microprocessor can determine that the relay is not open, and take appropriate predetermined action, e.g. sending a fault signal.
The current transformer 198 further provides the microprocessor with information about the current provided to the fan motor 30. With this information the microprocessor can detect existing or imminent problems with the fan motor 30, including for example start winding failure, run winding failure, and/or a seized rotor, and take appropriate predetermined action.
The microprocessor 184 also operates relay 202 via connection 204 to connect compressor motor 32 on terminals 138, 140, and 142 to 220 VAC. Because the relay 202 is on the same board as the microprocessor 184, the contacts 206 and 208 of the relay can be connected to the microprocessor, so that the microprocessor can determine when the relay 202 is open and when it is closed. The sensor 214 monitors the relay 202 for a spark, and provides the microprocessor 184 with information about the duration of the spark. The microprocessor can be programmed to reduce and/or to minimize the duration of the spark by adjusting the point at which the microprocessor signals the relay 202 to close relative to phase of the power line so that the relay closes at or close to the zero crossing to reduce arcing and thereby increase the life of the relay.
After the microprocessor opens or closes the relay 202, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 206 and 208. Thus when the microprocessor sends a signal to close the relay 202, and does not detect line voltage or current on contact 208, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 202, and still detects line voltage or current on contact 208, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
The current transformer 210 provides the microprocessor 184 with information about the current provided to the run winding of the compressor motor 32. The current transformer 218 provides the microprocessor 184 with information about the current provided to the start winding of the compressor motor 32. The current transformer 222 provides the microprocessor 184 with information about the current provided to the compressor common terminal of the compressor motor 32. With this information the microprocessor can detect existing or imminent problems with the compressor motor 32, including for example start winding failure, run winding failure, and/or a seized rotor, and take appropriate predetermined action.
A second embodiment of unitary control in accordance with the principles of this invention, adapted for use with a two stage air conditioning system, is indicated as 100′ in
The unitary controller 100′ also has a power bus 116 with terminals 118, 120 and 122 for connecting L2 and L1 and COM from a 220 VAC power source 26.
The unitary controller 100′ also has a connector block 130 with two terminals 132 and 134 for connecting to a condenser fan 30; a connector block 136 with three terminals 138, 140 and 142 for connecting to common, run, and start leads of a compressor motor 32; and a connector block 144 with two terminals 146 and 148 for connection to a start capacitor 34. In addition, controller 100′ has a connector block 150 with two terminals 152 and 154 for connecting to the leads of a two stage compressor control 36; a connector block 162, having terminals 164 and 166 for connecting a temperature sensor 40 for compressor discharge temperature; a connector block 170. having terminals 172 and 174 for connecting an optional high pressure switch 44; and a connector block 176, having terminals 178 and 180 for connecting an optional low pressure switch 46. Provision could also be made for measuring the ambient air temperature.
As shown in
A condenser fan relay 190 is connected to microprocessor 184 via connection 192. The relay 190 may be a A22500P2 latching relay manufactured by American Zettler. The relay 190 has first and second contacts 194 and 196, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 196 of which is in communication with the microprocessor. As shown in
A compressor motor relay 202 is connected to microprocessor 184 via connection 204. The relay 202 may be a A22500P2 latching relay manufactured by American Zettler. The relay 202 has first and second contacts 206 and 208, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 208 of which is in communication with the microprocessor. As shown in
A current transformer 222, connected to the microprocessor 184 via connection 224, is on a line between terminal 118 of connector block 116 (which is connected to line L2 of 240 VAC source 26) and terminal 138 of connector block 136, for electrical connection to the common lead of the compressor motor 32.
A two step relay 226, connected to the microprocessor 184 via connection 228, has first and second contacts 230 and 232, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 232 of which is in communication with the microprocessor. The relay 226 may be a A22500P2 latching relay manufactured by American Zettler. Instead of relay 226, a a triac that is pulse width modulated can be used, which allows control over the power to the two-step solenoid so as to minimize heating of the solenoid. The relay 226 is connected between the common terminal 104 on the input bus 102, and the terminal 154 of the connector block 150, for selectively connected the two step selector 36, which is connected between terminals 152 and 154.
A connection 234 connects the compressor discharge temperature sensor 40 to the microprocessor, a connection 238 connects the high pressure switch 44 with the microprocessor, and a connection 240 connects the low pressure switch 66 with the microprocessor.
The current transformers 198, 210, 218, and 222 may be TX-P095800C010 current transformers manufactured by ATR Manufacturing LTD.
In operation, when the temperature in the space monitored by the thermostat 22 rises above the set point temperature of the thermostat, the thermostat sends a signal to the microprocessor 184. The microprocessor 184 operates relay 190 via connection 192 to connect fan motor 30 on terminals 132 and 134 to line voltage. Because the relay 190 is on the same board as the microprocessor 184, the contacts 194 and 196 of the relay can be connected to the microprocessor, so that the microprocessor can determine when the relay 190 is open and when it is closed.
After the microprocessor opens or closes the relay 190, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 194 and 196. Thus when the microprocessor sends a signal to close the relay 190, and does not detect line voltage or current on contact 196, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 190, and still detects line voltage or current on contact 196, the microprocessor can determine that the relay is not open, and take appropriate predetermined action, e.g. sending a fault signal.
The current transformer 198 further provides the microprocessor with information about the current provided to the fan motor 30. With this information the microprocessor can detect existing or imminent problems with the fan motor 30, including for example start winding failure, run winding failure, and/or a seized rotor, and take appropriate predetermined action.
The microprocessor 184 also operates relay 202 via connection 204 to connect compressor motor 32 on terminals 138, 140, and 142 to 220 VAC. Because the relay 202 is on the same board as the microprocessor 184, the contacts 206 and 208 of the relay can be connected to the microprocessor, so that the microprocessor can determine when the relay 202 is open and when it is closed. The sensor 214 monitors the relay 202 for a spark, and provides the microprocessor 184 with information about the duration of the spark. The microprocessor can be programmed to reduce and/or to minimize the duration of the spark by adjusting the point at which the microprocessor signals the relay 202 to close relative to phase of the power line so that the relay closes at or close to the zero crossing to reduce arcing and thereby increase the life of the relay.
After the microprocessor opens or closes the relay 202, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 206 and 208. Thus when the microprocessor sends a signal to close the relay 202, and does not detect line voltage or current on contact 208, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 202, and still detects line voltage or current on contact 208, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
The current transformer 210 provides the microprocessor 184 with information about the current provided to the run winding of the compressor motor 32. The current transformer 218 provides the microprocessor 184 with information about the current provided to the start winding of the compressor motor 32. The current transformer 222 provides the microprocessor 184 with information about the current provided to the compressor common terminal of the compressor motor 32. With this information the microprocessor can detect existing or imminent problems with the compressor motor 32, including for example start winding failure, run winding failure, and/or a seized rotor, and take appropriate predetermined action.
In a two stage air conditioning system, as shown in
After the microprocessor opens or closes the relay 226, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 230 and 232. Thus when the microprocessor sends a signal to close the relay 226, and does not detect voltage or current on contact 232, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 226, and still detects voltage or current on contact 232, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
A third embodiment of unitary control in accordance with the principles of this invention, adapted for use with a two stage air conditioning system, is indicated as 100″ in
The unitary controller 100″ also has a power bus 116 with terminals 118, 120 and 122 for connecting L2 and L1 and COM from a 220 VAC power source 26.
The unitary controller 100″ also has a connector block 124 with two terminals 126 and 128 for connecting to a run capacitor 28; a connector block 130 with two terminals 132 and 134 for connecting to a condenser fan 30; a connector block 136 with three terminals 138, 140 and 142 for connecting to common, run, and start leads of a compressor motor 32; a connector block 144 with two terminals 146 and 148 for connection to a start capacitor 34; a controller 100″ has a connector block 150 with two terminals 152 and 154 for connecting to the leads of a two stage compressor control 36. In addition, control 100″ has a connector block 156, with terminals 158 and 160 for connecting a reversing valve 38. The controller 100″ also has a connector block 162, having terminals 164, 166, and 168 for connecting compressor discharge sensor 40 and a coil temperature sensor 42; a connector block 170. having terminals 172 and 174 for connecting an optional high pressure switch 44; and a connector block 176, having terminals 178 and 180 for connecting an optional low pressure switch 46. Provision could also be made for sensing ambient air temperature as well.
As shown in
A condenser fan relay 190 is connected to microprocessor 184 via connection 192. The relay 190 may be a A22500P2 latching relay manufactured by American Zettler. The relay 190 has first and second contacts 194 and 196, at least one of which may be in communication with the microprocessor 184, but preferably at least the non-moving contact 196 of which is in communication with the microprocessor. As shown in
A compressor motor relay 202 is connected to microprocessor 184 via connection 204. The relay 202 may be a A22500P2 latching relay manufactured by American Zettler. The relay 202 has first and second contacts 206 and 208, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 208 of which is in communication with the microprocessor. As shown in
A current transformer 222, connected to the microprocessor 184 via connection 224, is on a line between terminal 118 of connector block 116 (which is connected to line L2 of 220 VAC source 26) and terminal 138 of connector block 136, for electrical connection to the common lead of the compressor motor 32.
A two step relay 226, connected to the microprocessor 184 via connection 228, has first and second contacts 228 and 230, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 208 of which is in communication with the microprocessor. The relay 226 may be a A22500P2 latching relay manufactured by American Zettler. Instead of relay 226, a triac that is pulse width modulated can be used, which allows control over the power to the two-step solenoid so as to minimize heating of the solenoid. The relay 226 is connected between the common terminal 104 on the input bus 102, and the terminal 154 of the connector block 150, for selectively connected the two step selector 36, which is connected between terminals 152 and 154.
A connection 234 connects the compressor discharge sensor 40 to the microprocessor, a connection 236 connects the coil temperature sensor 42 to the microprocessor, a connection 238 connects the high pressure switch 44 with the microprocessor, and a connection 240 connects the low pressure switch 66 with the microprocessor.
A first reversing valve relay 242, connected to the microprocessor 184 via connection 244, has first and second contacts 246 and 248, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 248 of which is in communication with the microprocessor. The relay 242 may be a A22500P2 latching relay manufactured by American Zettler. The relay 242 is disposed between terminal 108 on the input bus 102, and terminal 158 on connector block 156, for connection to the reversing valve 38. A second reversing valve relay 250, connected to the microprocessor 184 via connection 252, has first and second contacts 254 and 256, at least one of which may be in communication with the microprocessor 184, and preferably at least the non-moving contact 256 of which is in communication with the microprocessor. The relay 252 may be a A22500P2 latching relay manufactured by American Zettler. The relay 252 is disposed between terminal 114 on the input bus 102, and terminal 160 on connector block 156, for connection to the reversing valve 38.
A connection 232 connects the compressor discharge sensor 40 to the microprocessor, a connection 236 connects the high pressure switch 44 with the microprocessor, and a connection 238 connects the low pressure switch 66 with the microprocessor.
The current transformers 198, 210, 218, and 222 may be TX-P095800C010 current transformers manufactured by ATR Manufacturing LTD.
In operation, when the temperature in the space monitored by the thermostat 22 rises above the set point temperature of the thermostat, the thermostat sends a signal to the microprocessor 184. The microprocessor 184 operates relay 190 via connection 192 to connect fan motor 30 on terminals 132 and 134 to line voltage. Because the relay 190 is on the same board as the microprocessor 184, the contacts 194 and 196 of the relay can be connected to the microprocessor, so that the microprocessor can determine when the relay 190 is open and when it is closed.
After the microprocessor opens or closes the relay 190, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 194 and 196. Thus when the microprocessor sends a signal to close the relay 190, and does not detect line voltage or current on contact 196, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 190, and still detects line voltage or current on contact 196, the microprocessor can determine that the relay is not open, and take appropriate predetermined action, e.g. sending a fault signal.
The current transformer 198 further provides the microprocessor with information about the current provided to the fan motor 30. With this information the microprocessor can detect existing or imminent problems with the fan motor 30, including for example start winding failure, run winding failure, and/or a seized rotor, and take appropriate predetermined action.
The microprocessor 184 also operates relay 202 via connection 204 to connect compressor motor 32 on terminals 138, 140, and 142 to 220 VAC. Because the relay 202 is on the same board as the microprocessor 184, the contacts 206 and 208 of the relay can be connected to the microprocessor, so that the microprocessor can determine when the relay 202 is open and when it is closed. The sensor 214 monitors the relay 202 for a spark, and provides the microprocessor 184 with information about the duration of the spark. The microprocessor can be programmed to reduce and/or to minimize the duration of the spark by adjusting the point at which the microprocessor signals the relay 202 to close relative to phase of the power line so that the relay closes at or close to the zero crossing to reduce arcing and thereby increase the life of the relay.
For example, the duration of the spark may be used as an offset value that is added to a delay value used to adjust timing for the next actuation of switching means (e.g., latching means of the microprocessor 184) for actuating the relay 202 relative to the line voltage zero crossing. If the delay value exceeds one line cycle, a fractional part of the delay value may be used for the subsequent actuation. If no arcing is detected by the sensor 214, the foregoing offset value is substantially zero and the delay value remains substantially constant.
A method of determining whether the sensor 214 is operating as intended may be performed, for example, periodically and/or after an appropriate number of actuations has been performed. The microprocessor may subtract an appropriate offset value from a current delay value. The foregoing step may be repeated for a plurality of cycles of the line voltage. If a feedback signal from the sensor 214 is detected, the delay value can be recalculated to restore an appropriate value for relay control using the sensor 214. If no feedback signal is detected, another control method may be used as further described below. While an another control method is in use, if a feedback signal is restored, for example, for a predetermined number of cycles, the microprocessor may revert to relay control using the sensor 214.
In the event that the sensor 214 is not operational or is not being relied upon, other methods of controlling the switching means may be used. For example, one implementation of a method of operating a switching means to control the relay 202 is indicated generally in
Another implementation of a method of operating a switching means to control the relay 202 is indicated generally in
Many implementations are possible, including implementations in which negative delay counters, negative offsets and/or other fractional values are used.
After the microprocessor opens or closes the relay 202, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 206 and 208. Thus when the microprocessor sends a signal to close the relay 202, and does not detect line voltage or current on contact 208, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 202, and still detects line voltage or current on contact 208, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
The current transformer 210 provides the microprocessor 184 with information about the current provided to the run winding of the compressor motor 32. The current transformer 218 provides the microprocessor 184 with information about the current provided to the start winding of the compressor motor 32. The current transformer 222 provides the microprocessor 184 with information about the current provided to the compressor common terminal of the compressor motor 32. With this information the microprocessor can detect existing or imminent problems with the compressor motor 32, including for example start winding failure, run winding failure, and/or a seized rotor, and take appropriate predetermined action.
In a heat pump system with two stage cooling, as shown in
After the microprocessor opens or closes the relay 226, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 230 and 232. Thus when the microprocessor sends a signal to close the relay 226, and does not detect voltage or current on contact 232, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 226, and still detects voltage or current on contact 232, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
In response to a change in demand from heat to cooling, or vice versa, from the thermostat 22, the microprocessor 184 operates relay 242 via connection 244, or relay 252, via connection 254, to operate the reversing valve connected to terminals 158 and 160, to change is mode of operation from heating to cooling, or vice versa. Because the relays 242 and 252 are on the same board as the microprocessor 184, the contacts 246 and 248 of relay 242 and 256 and 258 of relay 252 can be connected to the microprocessor, so that the microprocessor can determine when the relays 242 and 252 are open and when they are closed.
After the microprocessor opens or closes the relay 242, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 246 and 248. Thus when the microprocessor sends a signal to close the relay 242, and does not detect voltage or current on contact 248, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 242, and still detects voltage or current on contact 248, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
Similarly, After the microprocessor opens or closes the relay 252, it can confirm that the relay is in fact open or closed with voltage/current signals from the contacts 256 and 258. Thus when the microprocessor sends a signal to close the relay 252, and does not detect voltage or current on contact 258, the microprocessor can determine that the relay is not closed, and take appropriate action, e.g. sending a fault signal. Similarly, when the microprocessor sends a signal to open the relay 252, and still detects voltage or current on contact 258, the microprocessor can determine that the relay is not open, and take appropriate action, e.g. sending a fault signal.
The microprocessor can also factor signals received from the condenser coil temperature sensor 42, the compressor discharge sensor 40, the high pressure switch 22 and the low pressure switch 46 to determine the state of the system and take the appropriate action, which can include sending fault signals, and or sequencing the system through one or more corrective actions. For example the various inputs to the microprocessor can indicate that the coils have frozen, and the microprocessor can automatically implement a defrost cycle. Alternatively, the various inputs to the microprocessor may indicate that the fan motor 30 or compressor motor 32 is not operating correctly, that in system with two stage cooling that the system did not successfully switch from first stage to second stage cooling (or vice versa), or in a heat pump system that the system did not successfully switch from heating to cooling (or vice versa). The microprocessor can switch parts of the system off and on again, or take other action to attempt to fix the problem, and/or shut the system down and/or send a fault signals.
The unitary control of each of the three embodiments allows the microprocessor to implement a wide variety of diagnostic tests and corrective actions and/or alarms, some of which are summarized in Table 2:
The various fault signals can be communicated by the microprocessor using various color and blinking patterns for LED 188, or through com port 186 for communication to the thermostat and/or download by a service technician.
This application is a divisional application of U.S. patent application Ser. No. 10/836,526 filed on Apr. 30, 2004 now U.S. Pat. No. 7,100,382, which claims the benefit of U.S. Provisional Application No. 60/490,000 filed Jul. 25, 2003. The disclosures of the above applications are incorporated herein by reference.
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| 4864157 | Dickey | Sep 1989 | A |
| 5064998 | Holling | Nov 1991 | A |
| 5676196 | Jakubzick et al. | Oct 1997 | A |
| 5821642 | Nishhira et al. | Oct 1998 | A |
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| Number | Date | Country | |
|---|---|---|---|
| 60490000 | Jul 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10836526 | Apr 2004 | US |
| Child | 11514607 | US |
