Abstract: A system and method for managing energy consumption of a building system includes a source of actual energy consumption data, a source of actual weather data, and a database correlating discrete weather data values with expected energy consumption values for at least one component of the building system. A computer accesses the actual weather data, actual energy consumption data and database, wherein the computer compares the expected energy consumption values with actual energy consumption data and generates an output based on the comparison. The expected energy consumption values are generated for the discrete weather data values using an energy consumption model that functionally relates discrete weather data values and design information for the building system component.

Abstract: A zoned HVAC system is provided with a series of dampers. A control for the dampers causes the dampers to each move between open and closed positions while monitoring a system condition. The system condition is selected to be one that should change as the damper moves between open and closed positions. If the system condition does not change as the control orders the damper to move between the open and closed positions, the particular damper is identified as a potentially faulty damper.

Abstract: A condensate overflow prevention assembly prevents condensate overflow in an air cooling system using a fluid level sensor and a pump activated by the fluid level sensor to pump the condensate away from a drainage system when a blockage occurs in the drainage system.

Abstract: A refrigeration system including a compressor, condenser, valve, and refrigeration branch, all of which is in fluid communication. The refrigeration branch includes an evaporator coil. The refrigeration system further includes a case adapted to be cooled by the evaporator coil, and a system controller operable to control one or more aspects of the refrigeration system, and a subsystem controller in communication with the system controller. The subsystem controller is operable to control a subsystem having one of the compressor, condenser, valve, refrigeration branch, and case. The method of operating the refrigeration system includes at the subsystem controller, monitoring a parameter of the subsystem, comparing the monitored parameter with a parameter limit, generating an alarm when the parameter is not within the parameter limit, and communicating the alarm to the system controller.

Abstract: A control and method are disclosed to determine the relative duct sizes of a plurality of ducts leading to a plurality of zones in a multi-zone HVAC system. In a disclosed method, the dampers leading to each of the zones are operated such that one damper is held more open than the remaining dampers, and a system component is monitored as air is blown through the duct. In particular, a blower speed may be monitored. Once the blower speed is monitored, for one damper being open, with the remaining dampers being relatively closed, another damper is opened and the first is closed. This process continues until relative information is gathered for each of the zones. This relative information is then utilized to determine the relative sizes of the ducts leading to each of the zones as a percentage of the total duct size. The relative duct size information is then utilized to perform various control methods.

Abstract: An air conditioning or refrigeration system includes an expansion device that has a plurality of operating positions. When the expansion device is in a fully open position, the expansion device provides an indication to a system controller regarding that position. The controller responsively determines if the fully open position of the expansion device is caused by an undesirably low amount of refrigerant charge in the system. In one example, the controller rules out other possible reasons for the expansion device being in the fully open position. In one example, the controller automatically shuts down appropriate portions of the system to avoid any component damage that may result from having too low refrigerant amount in the system.

Abstract: A system for remotely monitoring operations of an HVAC system such as a chiller system having a control center, or a rooftop unit. The system utilizes a remote monitoring unit (RMU) located on-site. The RMU is in one-way communication with the component of the air conditioning system and receives data indicative of the operation of the component and determines whether the component is operating outside the normal operating parameters. When the RMU determines, from the data, that there is a problem that is within a critical parameter range, then a critical alarm is generated and the RMU opens a line of communication with a remote monitoring diagnostics device (RMD) located at the facility of the HVAC or refrigeration manufacturer and downloads the information to the RMD which determines whether remedial action is required and initiates remedial action if required.

Abstract: Methods, systems and devices for identifying irrational results from an engine coolant temperature (ECT) sensor in a vehicle are described. The vehicle suitably includes a processor in communication with the ECT sensor and an intake air temperature (IAT) sensor. The method includes the steps of receiving an ECT reading from the ECT sensor and a IAT reading at the processor, evaluating a temperature difference between the ECT reading and the IAT reading to determine if irrationality is present, and providing a fault indication in response to the evaluating step. The evaluating step includes monitoring the IAT reading during operation of the vehicle to identify the presence of an engine block heater if the temperature difference exceeds a pre-determined threshold.

Abstract: An auger-type ice making machine has an abnormality detecting device which detects a freezing of an ice-scraping auger on the basis of a hunting of current flowing through an auger motor 25. Current flowing through the auger motor 25 is taken out by a current-voltage converter 45, and an instantaneous value of the taken-out voltage,waveform every predetermined time is A/D converted by an A/D converter 52 which is provided at a controller board 50.

Abstract: A method of operating a directed relief valve (28) for an air conditioning system (10) preferably for a vehicle. The air conditioning system (10) includes a compressor (12), a condenser (16), an expansion device (20), and an evaporator connected to one another by refrigerant lines. The system (10) also includes the directed relief valve (28), which is disposed inline with at least one of the refrigerant lines to ventilate the refrigerant. The directed relief valve (28) includes a detonable squib (36) that explodes in response to a ventilation signal. A controller (40) generates the ventilation signal in response to a refrigerant leak being detected by a sensor (38). The sensor (38) is preferably located within an air space (27) and adjacent to the evaporator (22). If there is a malfunction of one of a plurality of sensors (38), a partial malfunction message is sent to the operator.

Abstract: A refrigerant filter/dryer assembly isolates, removes, and replaces a filter/dryer core, and allows the vapor-compression heat pump system to continue to operate while the filter/dryer is being replaced. The refrigerant flow is automatically by-passed and the filter/dryer core is isolated for removal. The filter/dryer easily connects back into the refrigerant flow path. An indicator can be provided for indicating the remaining useful life of the filter/dryer while it is being used in the system.

Abstract: A controlled method for an energy-saving and energy-releasing air conditioning discloses the energy-saving and energy-releasing actions performed by the two adjoined heat exchangers of the storage means. The feature of this design is to meet refrigerating and heat-produced requirements by using the controlled method of the present invention. Automatically adjusting the refrigerant flow rates of the first and the second circular refrigerant loops can place it into the optimum operational condition while central air conditioner is either under high loading or under low loading condition.

Abstract: A non-intrusive refrigerant charge level indicator includes a structure for measuring at least one temperature at an outside surface of a two-phase refrigerant line section. The measured temperature can be used to determine the refrigerant charge status of an HVAC system, and can be converted to a pressure of the refrigerant in the line section and compared to a recommended pressure range to determine whether the system is under-charged, properly charged or over-charged. A non-intrusive method for assessing the refrigerant charge level in a system containing a refrigerant fluid includes the step of measuring a temperature at least one outside surface of a two-phase region of a refrigerant containing refrigerant line, wherein the temperature measured can be converted to a refrigerant pressure within the line section.

Abstract: A check device for an air conditioning system of an automobile and an air conditioner compressor includes a first path for containing coolant flowing therein. An air conditioner compressor, a condenser, an inflate valve and an evaporator are sequentially mounted to the first path to divided the first path. Two opposite ends of the first path respectively connected to a high-pressure outlet and a low-pressure inlet of the air conditioner compressor. Two pressure gauges are respectively mounted to the first path, one before the air conditioner compressor and the other after the air conditioner compressor relative to the flowing direction of the coolant in the first path for showing the difference of the pressure value of the coolant between passing before the air conditioner compressor and passing after the air conditioner compressor.

Abstract: A refrigerating appliance with an inner chamber enclosed by a heat-insulating housing and a plurality of electrical or electromechanical components. The components including a cooling circuit for cooling the inner chamber and at least one temperature sensor. A control unit for controlling the cooperation of the components, which control unit has a test operating mode for checking the operative ness of at least some of the components.

Abstract: The Power Out Indicator can be engineered to utilize more than one source of energy such as a battery, solar cell, or any other source of energy for the purpose of recording numerical data. Refrigerators and Freezers on the market today have no way to notify the consumer how long they have been without power. The Indicator gives the consumer piece of mind that their perishables are safe to consume.

Abstract: A vapor-compression refrigerant cycle includes a variable displacement compressor for compressing refrigerant, a control unit for controlling the displacement of the compressor. The control unit includes a lock determining means for determining a lock of a sliding portion of the compressor, and the lock determining means determines that the sliding portion of the compressor is locked, when a control signal where the displacement of the compressor is equal to or larger than a predetermined value is output from the control unit, and when an absolute value of a temperature difference between an air temperature before being heat-exchanged in a low-pressure heat exchanger of the vapor-compression refrigerant cycle and the air temperature after being heat-exchanged in the low-pressure heat exchanger is equal to or smaller than a predetermined temperature. Therefore, the lock of the compressor can be accurately detected.

Abstract: The invention relates to a method of predicting the temperature of articles (P) passing through the chamber (2) of a cooling installation using a coolant (4), said method comprising a step whereby the temperature of articles (P) exiting said chamber (2) is predicted. Said prediction is calculated from the characteristic quantities in relation to the operation of said chamber (2), the thermodynamic and physical characteristics of said chamber (2) and the thermodynamic and physical characteristics of said articles (P). The invention is suitable for controlling quick-freezing tunnels for food.

Abstract: A power bus, connected to a 24V isolated power supply, is provided in a refrigerator where removable shelves can be selectively connected to it. Each shelf has a user interface and a circuit to control a microenvironment within the refrigerator, partially bounded by the shelf. Data between the shelf and a control circuit in the refrigerator can be transmitted over the power bus, or by other methods.

Abstract: A control device is provided in a vehicle to control an air conditioning apparatus and thereby to control ventilation and air conditioning of a passenger room of the vehicle. A mobile device communicates with the control device in a parked state of the vehicle to selectively control a first device, which performs ventilation of the passenger room, and a second device, which performs air conditioning of the passenger room, of the air conditioning apparatus in such a manner that at least one of the first device and the second device is selectively operated upon reception of a corresponding operational instruction from the operating device.

Abstract: A method for detecting compressor degradation includes the steps of providing a dataset for a compressor relating compressor operating parameters to each other; detecting real time actual values of the compressor operating parameters including an evaluated operating parameter; using at least one of the real time actual values and the dataset to determine a predicted value of the evaluated operating parameter; and comparing the predicted value of the evaluated operating parameter to the real time actual value of the evaluated operating parameter. This advantageously allows a prognosis of compressor performance to determine whether performance degradation is occurring.

Abstract: The invention proposes an air conditioning system for motor vehicles which is fitted with an injection computer and an electronic control device. The system comprises a first measuring member suitable for supplying a value relating to the pressure of the fluid at a first point in the air conditioning circuit which is situated between the outlet of the expansion member and the outlet of the evaporator, and a second measuring member suitable for supplying a value relating to the pressure of the fluid at a second point in the air conditioning circuit which is situated at the inlet to the compressor. The electronic control device makes use of the solution of an equation which relates the mass flow rate of the refrigerant fluid to the difference in pressure between the first point and the second point in order to calculate an estimate of a magnitude relating to the refrigerant fluid.

Abstract: The present invention provides an apparatus that is used to measure relative humidity, such apparatus comprises a housing having a first end and a second end. There is a humidity sensor disposed at the first end of the housing for measuring the humidity in the air and a temperature sensor also disposed at the first end of the housing for measuring ambient temperature. The apparatus has an electronics portion in direct electrical communication with the humidity sensor and the temperature sensor for computing a relative humidity and a dewpoint temperature. The electronics portion is disposed within a center portion of the housing. There is, further, a battery that is in electrical communication with the electronics portion, the humidity sensor and the temperature sensor for providing power to the apparatus. Such battery is disposed in the center portion of the housing of the apparatus.

Abstract: A refrigerated appliance includes a power interrupt system for detecting an out-of-range temperature condition in a fresh food or freezer compartment after a power interruption. The power interrupt system includes a central processor including a memory storage module and a plurality of temperature sensors. In operation, the power interrupt system compares sensed temperature values with stored temperature variables. If, after a power interruption, a compartment temperature exceeds a stored temperature variable by a defined amount, an over-temperature flag is triggered. Preferably, a display unit flashes an indication of the highest temperature reached by each compartment intermittently with the current compartment temperatures and an indication that a power interruption has occured. In this manner, a consumer can make an informed determination whether food stored within the appliance has been exposed to temperatures high enough to cause spoilage.

Abstract: Methods of diagnosing a temperature control unit and methods of performing a diagnostic check on a temperature control unit. The methods generally include monitoring at least one function of the temperature control unit, storing information relating to the at least one monitored function, determining from the information relating to the at least one monitored function whether the unit has a malfunction. Some methods generally include setting a flag to one of a first setting and a second setting, the flag being set to the first setting if the unit has no malfunction and the flag being set to the second setting if the unit has at least one malfunction, and enabling the diagnostic check when the flag is set to the first setting.

Abstract: A programmable thermostat having a touch screen liquid crystal display in which the power consumption of each heating/cooling component and the energy costs in the locality are entered by a user in order that the thermostat's control program can, upon demand, calculate and display the heating/cooling costs accrued beginning with a user-specified starting date.

Abstract: Methods and apparatus for monitoring power outages in a household appliance such as a refrigerator are disclosed. According to the method, a household appliance determines a prior occurrence of a power outage to the appliance. The household appliance then computes a duration of the power outage. Further, the household appliance alerts a user of the duration of the power outage.

Abstract: The invention relates to a method of refrigerant level monitoring in a refrigerant circuit of an air-conditioning or heat-pump system having a compressor and a refrigerant which may, depending on the operating point, be operated in the supercritical range. The method includes standstill level monitoring with the compressor switched off and/or in-operation level monitoring with the compressor switched on. In the case of in-operation level monitoring, the refrigerant overheat (dTü) at the evaporator is registered and, in the event of excessive overheat, it is concluded that there is underfilling. At a standstill, the pressure and temperature of the refrigerant are registered, and it is concluded that there is an improper refrigerant filling level if the pressure (pKM) lies below a minimum pressure value (pmin) or the temperature (TKM) lies above a maximum saturation temperature value (Ts) with the pressure being outside a predefinable intended pressure range ([pu,po]).

Abstract: A system and method for managing energy consumption of a building system includes a source of actual energy consumption data, a source of actual weather data, and a database correlating discrete weather data values with expected energy consumption values for at least one component of the building system. A computer accesses the actual weather data, actual energy consumption data and database, wherein the computer compares the expected energy consumption values with actual energy consumption data and generates an output based on the comparison. The expected energy consumption values are generated for the discrete weather data values using an energy consumption model that functionally relates discrete weather data values and design information for the building system component.

Abstract: A compressor includes a motor protector which stops the compressor motor when it senses an out of specification condition. A diagnostic system monitors the status of the motor protector and includes logic circuitry that diagnoses the type of problem the compressor or the system is having based upon the running times and status of the motor in conjunction with the times and status of the tripped motor protector. The diagnostic system also includes either a discharge pressure sensor or a condenser temperature sensor, an ambient air sensor and a voltage sensor. The sensors provide information to the diagnostic system, which enable it to determine where a system fault has occurred.

Abstract: A system and method for switching a communication mode of a pad-detachable refrigerator, wherein the attachment/detachment of a client pad to/from the refrigerator is sensed and the communication mode of the refrigerator with the client pad is switched to a wired/wireless communication mode according to the sensed result so that signals can be transmitted and received in the switched communication mode. The client pad is detachably attached to the outer surface of the refrigerator. A communication module set is installed in the refrigerator to transmit and receive signals to/from the client pad by wire or wirelessly. A refrigerator control unit is adapted to control the communication module set to automatically switch the communication mode of the refrigerator with the client pad to the wired/wireless communication mode according to the attachment/detachment of the client pad.

Abstract: A leak detection system for the detection and monitoring of pressurized refrigerant systems, primarily walk-in refrigeration units in stores or storage facilities, manages, monitors and controls the refrigeration system which store and preserve perishables. The system includes a gas refrigerant detector and a monitor and relay system to alert the store personnel and remote monitoring stations that a problem exists by detecting the presence of gas outside the system within the refrigeration units, assessing the magnitude of the problem, and providing an emergency shutoff means to close and contain the refrigeration system contents in the event a substantial refrigeration leak is detected, closing the system until system repairs are made and the system is reset.

Abstract: A control system is provided to maintain stable operating conditions for centrifugal compressors operating in parallel when one of the centrifugal compressors enters into an unstable operating condition. The control system determines an unstable operating condition in response to signals indicating the motor current or power consumption of each compressor and the position of the pre-rotation vanes of the compressors. Once an unstable operating condition is determined, the control system closes the pre-rotation vanes to each compressor until the unstable operating condition has been corrected.

Abstract: A refrigerator having a removable shelf with a user interface for setting the working conditions of a refrigerator compartment. The user interface also being able to transmit the working conditions to a control unit of the refrigerator. The refrigerator having a package to be inserted in the refrigeration compartment, the package supporting a plurality of inductors for receiving and transmitting data to the user interface.

Abstract: A system and method for determining engine operation for a start-stop vehicle is provided. The start-stop vehicle includes an HVAC system. The engine operation control system includes an HVAC control head for indicating demand, a sensor for indicating fan speed, at least one sensor for indicating ambient air temperature, and a powertrain control module in communication with the HVAC control head and the sensors. The powertrain control module determines engine operation. The method for controlling engine operation includes the steps of determining HVAC demand, fan speed, and ambient temperature to a control module. The control module determines engine operation based on the signals from the signal generators of the HVAC demand, the fan speed, and the ambient temperature.

Abstract: A refrigeration container is provided with a manually operated fresh air vent with a position sensor which provides a signal to the microprocessor based controller indicative of the position of the fresh air vent. The fresh air vent controls both the providing of fresh air to the circulating air in the container and the exhausting a portion of the circulating air. The evaporator fan is run continuously when the air vent is open to prevent the build up of gases produced by the perishable cargo.

Abstract: A cooling system includes a compressor having a motor protector which stops the compressor's motor when it senses an out of specification condition. A diagnostic system of the cooling system monitors the status of the motor protector. The diagnostic system includes logic circuitry that diagnoses the type of problem the compressor or the system is having based upon the running times and status of the motor in conjunction with the times and status of the tripped motor protector. The diagnostic system also includes either a discharge pressure sensor or a condenser temperature sensor, an ambient air sensor and a voltage sensor. The sensors provide information to the diagnostic system to enable it to determine and indicate a system fault.

Abstract: A combination P-trap, shutoff switch and cleanout fitting for installation in a drain line has a hollow generally cylindrical body with a central chamber, an integrally formed tubular inlet and outlet, and a removable cap with a depending float switch which is disposed in the chamber. The float switch is electrically connected between the thermostat and air handler unit. The inlet conducts liquid from a drain pan into the lower portion of the chamber beneath a partition and the outlet conducts water from the upper portion of the chamber into the downstream portion of the drain line. When the surface of the liquid in the chamber is above the partition the device functions as a P-trap to prevent backflow of undesirable gases and odors from downstream being drawn up through the drain line by the air conditioner recirculation fan and entering into the system.

Abstract: A method for detecting a low-charge state in an air conditioning system. In one aspect, the temperature/pressure of the discharge of the condenser is measured to determine whether a low-charge state exists in the refrigeration system by calculating the degrees of subcooling of the refrigerant and comparing that to a predetermined minimum value. In another aspect, the temperature/pressure of the discharge of the compressor is measured to determine whether a low-charge state is indicated by calculating the degrees of superheat of the refrigerant and comparing that value with a predetermined maximum value. An air conditioning checker is also disclosed.

Abstract: The present application reveals a simplified method and a device for diagnosing performance of an air-conditioning system. The simplified method comprises determining a temperature differential or differentials between inlet and outlet temperatures of a condenser and/or between ambient and vent temperatures in the air-conditioning system; analyzing the differential or differentials to determine whether the air-conditioning system is properly functioning; and diagnosing performance of the air-conditioning system.

Abstract: In a refrigerant cycle system with a hot gas heater cycle, a pressure difference (&Dgr;Pd) between a high-pressure side refrigerant pressure of the hot gas heater cycle at a start of a heating mode and a high-pressure side refrigerant pressure of the hot gas heater cycle at a predetermined time after the start of the hot-gas heating mode is calculated. When the pressure difference (&Dgr;Pd) is in a predetermined range, it can be determined that the refrigerant is in a normal state. In this case, an electromagnetic clutch is turned on, and a compressor operates. On the other hand, when the pressure difference (&Dgr;Pd) is outside the predetermined range, it can be determined that the refrigerant is in a shortage state. In this case, the electromagnetic clutch is turned off, and the operation of the compressor is stopped.

Abstract: A refrigerator, comprising an oil deterioration judging device for judging a degree of deterioration of a refrigerating machine oil, wherein the oil deterioration of a refrigerating machine oil, wherein the oil deterioration judging device is disposed between a discharge side of a compressor and a gas closing valve, between a four-way directional control valve and the gas closing valve, or in a middle of a gas side connecting pipe.

Abstract: A system for monitoring conditions relating to the status of items such as perishable food products stored in enclosed spaces has a number of sensors mounted in the spaces. Tables maintained by the system hold a description of the spaces to be monitored and the location and identity of the sensors within each space. The values detected by each sensor are periodically recorded and tested against benchmark values established for the stored items adjacent to the sensor. Values outside of the benchmark values create an alarm condition, and a set of alarm messages are displayed on a display unit. The alarm messages include suggested corrective actions. The user has the opportunity to signal to the system the corrective actions taken, and the system stores a record of these corrective actions in association with the corrective actions and the alarm condition.

Abstract: A refrigerator includes a cabinet for enclosing a refrigerating compartment, the cabinet having a door for providing access to the refrigerating compartment, a user interface operatively connected to the cabinet having a display for displaying refrigerator function selections and a plurality of buttons for selecting refrigerator functions and a control unit operatively connected to the user interface and adapted to control a plurality of refrigerator functions. The control unit can be adapted for determining refrigerator filter information and displaying refrigerator filter information, the refrigerator filter information can include a date associated with the refrigerator filter.

Abstract: Methods and apparatus for monitoring power outages in a household appliance such as a refrigerator are disclosed. According to the method, a household appliance determines a prior occurrence of a power outage to the appliance. The household appliance then computes a duration of the power outage. Further, the household appliance alerts a user of the duration of the power outage.

Abstract: Apparatus and method of monitoring operation of a temperature control apparatus. The apparatus includes a controller, a refrigeration circuit extending between a compressor, a condenser, and an evaporator, and a drive unit operably connected to the compressor. The drive unit has a fuel supply, a plurality of cylinders, a fuel line extending between the fuel supply and the plurality of cylinders, and a sensor positioned between the fuel supply and the cylinders to record fuel flow. The method includes directing air across the evaporator, recording a fuel flow rate with the sensor, calculating an actual output power of the drive unit using the fuel flow rate, calculating an expected output power of the drive unit, and comparing the actual output power of the drive unit and the expected output power of the drive unit to predict malfunctions of the apparatus.

Abstract: The invention relates to a method of refrigerant level monitoring in a refrigerant circuit of an air-conditioning or heat-pump system having a compressor and a refrigerant which may, depending on the operating point, be operated in the supercritical range. The method includes standstill level monitoring with the compressor switched off and/or in-operation level monitoring with the compressor switched on. In the case of in-operation level monitoring, the refrigerant overheat (dTü) at the evaporator is registered and, in the event of excessive overheat, it is concluded that there is underfilling. At a standstill, the pressure and temperature of the refrigerant are registered, and it is concluded that there is an improper refrigerant filling level if the pressure (pKM) lies below a minimum pressure value (pmin) or the temperature (TKM) lies above a maximum saturation temperature value (TS) with the pressure being outside a predefinable intended pressure range ([pu,po]).

Abstract: A process for estimating the capacity and the coefficient of performance by taking common measurements and using compressor manufacturer's performance data is presented. A process for determining a capacity index and an efficiency index for a vapor compression cycle relative to desired operating conditions.

Abstract: An air conditioner and method of detecting a refrigerant leakage in the air conditioner in which the entire refrigerant pipe of the air conditioner is sectioned based on expansion valves into a plurality of sections, the sections are checked one by one to quickly detect a refrigerant leakage from the sections and an exact position of a broken or loosened area of the refrigerant pipe causing such a refrigerant leakage is found. In the method of detecting a refrigerant leakage in the air conditioner, comprising a compressor, an expansion valve, an outdoor heat exchanger, and an indoor heat exchanger connected to one another by a refrigerant pipe, the refrigerant pipe is sectioned into a high pressure section extending from the outlet port of the compressor to the inlet port of the expansion valve, and a low pressure section extending from the outlet port of the expansion valve to the inlet port of the compressor. A pressure sensor is provided on the refrigerant pipe within the low pressure section.

Abstract: A refrigeration system for cooling a logic module includes an evaporator housing including an evaporator block in thermal communication with the logic module. The evaporator housing includes a humidity sensor for detecting a humidity within the evaporator housing. The system further comprises a controller for controlling a refrigeration unit supplying cold refrigerant to the evaporator block in response to the operating conditions of the logic module and the temperature of the evaporator block. In another aspect of the invention, two modular refrigeration units are independently operable to cool the evaporator block, and each refrigeration unit is controllable in various modes of operation including an enabled mode in which it is ready to cool the evaporator and an on mode in which it is actively cooling the evaporator. In another aspect of the invention, the evaporator block and a heater on a reverse side of the circuit board are particularly controlled during concurrent repair operations.