About inverter air conditioner fault repair skills
Today I will share with you the maintenance ideas and cases about the failure of the inverter air conditioner that does not heat but can cool. If you like, you can like it and collect it, thank you!!!
First of all, let’s talk about the failure of the four-way reversing valve when it is not heating and cooling. There are basically the following reasons: the heating effect of the air conditioner is poor, just add "fluorine"? No, these aspects are not yet checked!
(1)Four-way valve coil failure; (2) Four-way valve body failure; (3) Four-way reversing valve control circuit failure on the outdoor unit computer board; (3) Indoor unit temperature sensor failure; (4) Electromagnetic interference, such as: poor indoor and outdoor grounding wire connection, damage to the interference elimination device connected to the relay contact switch, etc.; (5) Too low voltage causes the four-way valve to not work normally. Let's talk about the cases encountered in maintenance.
Example 1: No heating, normal cooling, and oil stains on the shut-off valve nozzle of the outdoor unit.
Fault analysis: Probably there is refrigerant leakage in the system, which causes the system pressure to be low and the four-way reversing valve cannot be operated.
Troubleshooting: After testing, it is found that the pressure is indeed low. After shutting down, check the oil-stained parts and confirm that the blister copper tube horn is not tightened in place. After re-tightening, add refrigerant to eliminate the fault.
Example 2: The fan in the heating does not rotate, and the refrigeration operates normally.
Fault analysis: This is the phenomenon that the indoor unit thinks that the temperature of the inner coil is low and performs cold wind protection. Generally, it is caused by abnormal resistance of the inner coil sensor, and the computer board of the indoor unit is faulty.
Troubleshooting: After checking that the indoor coil temperature is very hot, far exceeding the anti-cold air value of 25 degrees, check the inner coil temperature sensor in turn. After measurement, it is found that the resistance value has greatly drifted, and it is judged that the internal coil temperature sensor is damaged, and the boot is normal after replacement.
Example 3: The unit is also cooled normally, and cool air is produced.
Failure analysis: There is a problem with the four-way reversing valve.
Troubleshooting: First check the valve body and find that the pipe connected to the outdoor condenser is hot, indicating that the unit is in a cooling state; the resistance value of the four-way valve coil measured is incorrect, the normal value should be 700-2000, indicating that the coil has been damaged, replace the corresponding model After that, the boot is normal.
Example 4: Hisense KFR-50LW/26VBP does not heat but can be cooled, and the four-way valve coil does not have 220VAC.
Case analysis: It is judged that there is a problem with the four-way valve circuit. Failure detection of four-way valve of air conditioner
Troubleshooting: Test that the output terminal controlled by the four-way valve of the reverse drive is 0.8v low-level heating value, indicating that the fault lies in the relay. Measure the coil resistance again. Everything is normal. There is a "click" sound when switching. It is suspected that the relay contact is oxidized due to long-term use. Although it is closed, the contact switch cannot be turned on normally. After replacing the relay, the air conditioner Heating is normal.
Troubleshooting: First compare the resistance and voltage of the lower indoor coil temperature sensor and the room temperature sensor, and they are basically the same after inspection. Then the indoor coil sensor is heated and tested, and its resistance becomes smaller. This indicates that the temperature collection circuit composed of the indoor coil temperature sensor and the room temperature sensor is normal, which may be caused by an open circuit of the inductance or isolation resistor.
Perform the next measurement again and find that the inductor is open, replace it and eliminate the fault.
