Haier AU282AHBEA Service Manual page 300

9) Over current protection
start
Is supply voltage too low?
Especially when compressor runs
at a high frequency.
no
Are power cables L, N and
compressor wires U, V and
W properly connected
correctly?
yes
Is compressor current higher than current
protection limit? Is current sensing circuit in good
condition?
yes
1. Is module output voltage among U, V and W
balanced?
2. Disconnect all terminals. Is resistance of the
power module between P and N; P and U, V, W; N
and U, V, W acceptable?
yes
if compressor is normal
yes
if rectifier is normal
yes
Are capacitance and conductivity
values of electrolytic capacitor
acceptable?
yes
Is pressure normal?
no
Check: 1. Is a valve in system close?
2. Is piping clogged;
3. Is system overfed; is there air in system;
4. (Cooling cycle) Is condenser dirty? Does outdoor fan motor run at
low speed or stop?
5. (Heating cycle) Is evaporator or filter dirty? Does indoor fan motor
run at low speed or stop?
6. Is ambient temperature too high? Is system overloaded?
yes
Modify power supply circuit
no
connect firmly
no
no
no
Is compressor winding resistance
acceptable? Is it stuck?
1. Check diode characteristics of rectifier+, AC; - AC
no
2. Measure voltage between P and N, which should be 310VDC at 220VAC.
After compressor runs, the value should reduce
no
Replace electrolytic capacitor
>a__WcU[S^ <[c >a`V[e[a`Wc
detecting circuit is
abnormal. Replace
outdoor PCB
replace power module
yes
replace compressor
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