AUX air conditioner service manual
183
(5)Heat pump air conditioner fails to heat
If air conditioner can produce cooling air but fail to produce heating air, there must be some faults in
magnetic reversing valve or switch.
① Magnetic loop of magnetic valve has burnt out or broken out because of:
a、 Operate in severe environment;
b、Magnetic loop stops and starts up frequently;
c、 Operate under excessive voltage for a long time so that loops run under high temperature rise
and insulation layer has been damaged.
② Spool in magnetic valve has jammed or damaged because of:
a、 Foreign substance has entered valve and jammed spool;
b、Spool has been damaged because of poor quality.
③ Reverse valve fails to work because of different reasons, but in most cases, impacted by
unclean refrigerant and poor manufacture or assembly quality.
④ Cool-heat switch fails to operate because of damaged structure and oxidized contact surface
⑤ Electric Leakage
Electric leakage on the surface resulted from declined insulation property, being affected by damping,
poor ground wire or even no ground wire connected.
2. Fault Analysis for Electronic Circuit Control System
Control panel of electronic circuit control system is a circuit with 5V or 12V low voltage, which is a
kind of small, safe, reliable and attractive panel with more control functions comparing to the
Electrical Circuit Control System.
(1)Air conditioner fails to work after switched on
When function button pushed on, air conditioner fails to work, and creates no sound, under this
circumstance, electrical power is not connected and all appliances connected with electrical power
shall be checked as per following sequence:
① Check whether there’s current in electrical power wire. Devices controlling the electrical
power wire shall be checked, for example, whether knife switch or air switch is broken.
② Check whether there’s any phase lack. For example, for three-phase air conditioner, one or
two phases of three- phase power network may break off, or phase of electrical power wire
may break off.
③ Check whether fuse of control panel of indoor unit breaks off or piezo-resistor has been
damaged. Protector shall be installed to cut off service power before excessively high voltage
or large current enters the control circuit.
④ Check if socket connector between control panel wire of indoor unit and power wire contacts
well. Socket connector may be self-locked, but also it may be loose contacted.
⑤ Check if key switch fails to work, for example, whether buttons contact well or whether
components of buttons have been broken.
⑥ Check whether indoor electronic control panel has been broken. Circuit or electronic
components of control panel may be damaged.
(2)Indoor fan runs, while compressor fails to work and trouble light blinks.
Blinking trouble light shows that system has some problems, including faults in electrical appliance or
system.
① Phase lack of service power wire or over low voltage: check if voltage of power wire is 10%
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