Haier AB422XCBAA Service Manual page 167

11) Fault in drain system
confirm the malfunction
according to the fault code list
Is drain pipe clogged?
no
Is pump motor in
good condition?
yes
Is drain pan dirty and
float switch ineffective?
no
Is float switch holder tinted
that float can't move, or too
close to pump motor that
interference arises?
no
Check if float switch is in good
condition with multimeter
no
Replace indoor
PCB
Note: Float switch is close in normal state, when being activated, it is open.
Voltage between both ends is 0V when close, approximately 5V when open.
yes
Unclog pipe and
water pump
yes
Replace water
pump
yes
Clean drain pan
yes
Adjust holder
yes
Replace float
switch
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