Inspection and maintenance of air-conditioning thermostat

If the air conditioner does not run as usual, you have to do some tests. Moreover, you should check the electrical control system controls the protection and enforcement components, temperature control main selector switch. Here are a few common methods to check the thermostat.


First, the thermostat of the hot and cold dual

Using the same hot and cold temperature sensing bellows of control. Its failure to check the thermostat and general inspection method is basically the same, but it should be noted that you should also check hot and cold switching operation is sensitive, that is, turn on the compressor cooling circuit should be in the position, the heating should be in the ON position electric heater circuit. Electric air conditioner used in the thermostat, contact the control box has two sets of contacts mechanism (cold contact and thermal contact).

Second, the bellows or diaphragm thermostat

Symptom: temperature controller contacts since the ignition occurs after adhesion. Contacts are not automatically jump, the compressor can not stop.
How to repair: If disconnected. Show contact adhesion, available flat screwdriver to move the mechanical forced contact is open; if contacts can jump, Table H-month thermostat temperature range and low drift, adjustable temperature range adjustment screw clockwise.

The bulb on the refrigerator double door refrigerator (5 ~ lO ℃) within the measured temperature controller two-wire terminals are disconnected. 1. Symptom: Contact bad or burned, causing the circuit can not be turned on; frequent contact arcing motion adhesions, resulting circuit can not be broken; temperature refrigerant leak temperature chamber, causing the contacts can not lose control of its operation and the like.

How to repair: if not pass, may be temperature refrigerant leakage. Leaks can first visual inspection, the observed temperature sensor seal welding head is broken, whether the bulb is damaged and cracks, the temperature sensing tube bending Have marks, etc., and then release the bulb 30 ~ 40 ~ C's warm water, test contact is closed, if the contact is still closed. Temperature sensing agent showed temperature within the package has been completed leakage; if the contacts can be closed, then the bulb was removed from the water and place some time after contact and off at low temperatures, indicating thermostat range improper adjustment screw can be corrected by adjusting the temperature range, counter-clockwise l.

Two terminals being the thermostat knob, turn the opposite direction after a few times, with a multimeter R × l range measuring temperature controller on state, if the resistance value is very small, indicating that the contact normal; If the resistance is large, show contact poor contact.

fan coil unit thermostat

Third, the temperature-sensitive resistor

Temperature sensing control characteristic curve or characteristic table of values ​​to determine whether normal when thermistor aging, drift performance, namely when the corresponding relationship between temperature and resistance to change, should be replaced with a new thermistor sensor. Electronic thermostat or microcomputer-controlled air conditioner, are thermistor for temperature sensing element. Is a thermistor whose resistance changes with temperature significantly change elements. For an air conditioner return air temperature measured ten stand thermistor. Generally having a negative temperature coefficient characteristics: resistance value decreases with increasing temperature. Thermistor specific to a certain brand of deep space is used, its resistance changes with temperature characteristics are generally plotted in random specification chart for detection use can be detected under certain circumstances. Measured with a semiconductor thermometer and multimeter.

Fourth, the defrost temperature controller

The method is to detect the temperature sensing portion disposed corresponding to the temperature of the water or air. Measured with a multimeter two terminals is disconnected or turned on. You will know good or bad. Thermal bimetal thermostat is also used for anti-cold indoor side control. Defrost temperature controller is provided in the thermal-type air conditioner control circuit is designed for the switching element electromagnetic valve. Its temperature sensing tube in the outdoor heat exchanger coil on. When winter heating, the outdoor heat exchanger frost thickened the temperature falls below a set value. Defrost controller contact action. Disconnect the solenoid valve. So that the original heating cycle becomes refrigeration cycle. There are two common forms of structure: one is sensitive bimetal: one is ordinary thermostat.