65
Installation and Maintenance
Service Manual
17
Decrease
frequency due
to high air
discharge
F9
All loads operates normally,
while operation frequency of
compressor decreases.
Overload; ambient
temperature is too high;
1. Reduce load;
Refrigerant is not
enough
2. Add refrigerant
Malfunction of electronic
expansion valve
（
EKV
）
3. Replace electronic
expansion valve →
replace outdoor units
main board AP1
18
DC busbar
voltage is too
high
PH
During cooling and drying
operation, compressor stops
while indoor fan operates.
During heating operation, all
loads stop.
1. Measure the voltage
at position L and N on
wiring board (XT). If
the voltage is higher
than 265VAC, wait until
the power voltage is
decreased within normal
range and then turn on
the unit;
1. Check whether
power supply network is
abnormal;
2. If AC input is normal,
measure the voltage
between A and B ends
of electrolytic capacitor
(fig. 30 in 9.1) on control
board (AP1) after
turning on the unit. If its
normal, the circuit has
malfunction. Please
replace the main board
of outdoor unit.
2. Replace outdoor
units main board AP1;
19
Detection
malfunction of
system current
U5
During cooling and drying
operation, compressor and
outdoor fan stop while indoor
fan operates. During heating
operation, all loads stop.
Malfunction of circuit on
outdoor units main board
AP1. Replace outdoor
units main board AP1.
1. Replace outdoor
units main board AP1
