50
Installation and Maintenance
Service Manual
16
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 unit's
main board AP1
17
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 it's normal,
the circuit has
malfunction. Please
replace the main
board of outdoor unit.
2. Replace outdoor unit's
main board AP1;
18
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 unit's main
board AP1. Replace
outdoor unit's main
board AP1.
1. Replace outdoor unit's
main board AP1
