Haier HSU-18HEA03/R2(DB)-I Service Manual page 75

A
Check the status of LED1
on the indoor mainboard. If
the LED1 blinks
interruptedly
Test the outdoor power supply
(230VAC and +310VDC) with a
multimeter.
If both 230VAC and 310DC
are available,measure
+12V(from7805)
available.
YES
measure +5V(from7805) is
available.
YES
If the LED1 is off within two minutes
after the machine is supplied with
power, measure the AC voltage
between positions 1 and 3 on the
terminal of outdoor
multimeter.
If the value varies between 0 and 80
VAC, the outdoor mainboard is
damaged, replace it with a new one.
HSU-18HEA03/R2(DB)-I
No
If 230VAC is available but
310DC not, the power module is
damaged, replace it with a new
one.
is
unit with a
73
Yes
measure
Jumpers 3 and 4 of IC102 on the
indoor mainboard with a multimeter.
If the voltage is of a
constant value of 0V
DCto5V DC
The indoor mainboard is
damaged;
NO
with a new one.
The IPM module is damaged;
Replace them with a new one
The outdoor mainboard is
NO
damaged; Replace them with a
new one.
If the value is constant at about 30V,
the indoor mainboard is damaged,
replace it with a new one.
The outdoor mainboard is damaged;
replace it with a new one.
Service Diagnosis
the voltage between
YES
replace it
Domestic air conditioner
NO