【 Weak current College 】 inspection of air conditioning thermostat---Power By 【 China power house network 】

When the air conditioner is not working properly, you will need to check compressor start relay, thermal and over-current protector and capacitors, you must check the electrical control system is very important to control the protection and enforcement components — the temperature control in the master selection switch. Here are some common thermostat for rapid detection method.

First, the bellows-type or diaphragm type temperature controller

1. symptoms: contact bad or burned, causing the circuit can't reach; contact frequently starting arc adhesion, causing the circuit can't fault; thermal cavity temperature sensor for leak, causing the contacts cannot control the actions and lose.

Maintenance: the thermostat knob is in the opposite direction of rotation, several times, using a multimeter R×l stalls measuring temperature controller powered by two terminals, resistance is small, that contact is normal; if resistance, that contact is bad; if not, may be the temperature sensor for leak. If leakage can be first Visual inspection, observation of thermal head seal welding head is cracked, the sensor is damaged and crack, heat pipe has no bending trace, and then put the sensor placed people 30 ~ 40 ~ C warm water, test contacts closed, if the contact is still not closed, indicates that the sensor within the Thermo agent has been leaking out; if contact can be closed, then the sensor shall be removed from the water, put in the low temperature for a period of time after the contact has broken, the range of thermostat thermostat described incorrectly, you can adjust the temperature range of the adjusting screw rectifying, counterclockwise l/2 circle and try again.

2. failure phenomenon: temperature controller appears as a result of arcing contacts after adhesion. contact does not automatically jump to open, you cannot shut down the compressor.

Maintenance methods: put the sensor in two-door refrigerator storage room (5-lO ℃), the measuring temperature controller two terminals is disconnected. If disconnecting the. indicate contact adhesive, available flat blade screwdriver disconnect stirring the mechanical force-contact; if contact can jump off, table H-thermostat for temperature control range low drift and clockwise adjust temperature range adjustment screw.

3. failure phenomenon: temperature sensor for leak.

Maintenance methods: hot towel to heat pipe heating and the knob to the lowest temperature, multimeter measuring temperature controller is connected to the switch. If the switch is blocked. the thermal agent has been compromised, you should replace new thermostat.

Second, hot and cold-temperature controller

Electric-type air conditioners in the thermostat, contact control box has two sets of contact agencies (cold-contact and heat-contact), using the same thermal bellows control on cooling and heating degree. Its symptoms and inspection methods and ordinary thermostat are basically the same, but note that you should also check cooling load, thermal load switching is sensitive, i.e. in the refrigeration compressor should be connected to the location, the location in the heating circuit should be connected to the electric heater circuit.

3. defrost temperature controller

Defrost temperature controller is set in a hot-air conditioner control circuit for switching solenoid valve components. Its heat pipe installed side heat exchanger coil. when winter heating, outdoor side heat exchanger Frost layer thickening the temperature is below a set value when defrosting controller-contact action. Disconnect the solenoid valve £ ® the original heating cycle into a refrigeration cycle. Common structure there are two forms: one is the thermal bimetal: one is the normal temperature controller. Detection method is part of the temperature sensor is placed in the corresponding temperature of water or air, multimeter measuring two terminals is disconnected or conduction can know good or bad!. Thermal bimetal thermostat is also used to control indoor side against the cold wind.

4. heat resistance

Electronic thermostat or microcomputer control of the air conditioner, have made a thermistor sensor components. Thermistor is their resistance with temperature changes and significant change in the component £ ® for air conditioner return air temperature 10-lap direction of thermistors. General characteristics with a negative temperature coefficient: resistance with temperature increase and decrease. Specific to a certain brand of empty Yuan for the use of the resistance of the thermistor, it varies with temperature-dependent properties are generally draw in random directions into the chart for detection, detection can under certain circumstances, using a thermometer and a multimeter for semiconductor measurement. controlled temperature sensing characteristic or characteristic value table to determine whether the normal performance when aging, Thermistor, namely temperature drift and the resistance of the correspondence between the change and should be replaced with new thermistor sensors.

The system is not functioning properly or long term will have failed after aging. In the repair process can sometimes take a replacement method, which uses a good same model, same specifications thermostat replacement saves maintenance time and can easily distinguish the thermostat is good or bad.