Service manual


GB
Operation in Cooling Mode
Control of Expansion Valve in Cooling Mode
1. Reset of Expansion Valve
In the first time the expansion valves in all channels shall be shut do�n 600 steps, then
the expansion valve corresponding to the indoor unit in normal communications �ith the
outdoor unit shall be opened to standby mode steps. If accomplished, the outdoor unit shall
be on standby mode, until the turn-on the indoor unit.
2. Adjustment of Expansion Valve
1) Setting of Basic Step
After the confirmation of the turn-on order of cooling mode, the expansion valve of the
relevant indoor unit shall be set to the basic step and the other to zero step.
2) Adjustment of Expansion Valve according to the difference in temperature bet�een the
inlet and outlet of evaporator
During the first ten minutes of cooling mode, the expansion valve of the indoor unit at the
request of cooling shall be set to the basic step. Ten minutes later, the expansion valve step
and its adjust cycle shall be adjusted according to the difference in temperature bet�een
the inlet and outlet of evaporator.
Control of compressor’s frequency
1 . Range of compressor’s frequency: F
min
- F
max
(F
min
:the lo�est frequency, F
max
: the highest
frequency)
2 . Frequency decrease protection of compressor: frequency decrease protection is prior
during frequency adjustment of compressor (Frequency decrease protection have:
high temperature of compressor discharge, high temperature of outdoor coil pipe, high
temperature of indoor coil pipe, lo� temperature of compressor suction, over current)
Control of fan motor in cooling mode
1 . The fan motor of outdoor unit is ahead run 20 seconds before compressor turn on.
2 . After compressor turn off, the fan motor of outdoor unit delay 30 seconds.
3 . The fan motor speed of outdoor unit as belo� table in normal running, it has 20 seconds
delay after speed change.
Speed table of outdoor fan motor
outdoor ambient
2hp ≥2hp ≥3hp
cooling Speed grade
T=66
O
F lo� lo� middle
66
O
F≤T=81
O
F lo� middle high
T≥81
O
F middle high high