40 SERVICE MANUAL FOR AMERICA
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 down 600 steps, then the
expansion valve corresponding to the indoor unit in normal communications with 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 between 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 between the inlet and outlet of
evaporator.
Control of compressor’s frequency：
1．
Range of compressor’s frequency
：
Fmin
～
Fmax (Fmin
：
the lowest frequency, Fmax
：
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, low 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 below table in normal running, it has 20 seconds delay after
speed change.
Speed table of outdoor fan motor
indoor unit
capacity
outdoor ambient
＜
2hp
≥
2hp
≥
3hp
cooling Speed
grade
T
＜
66
O
F
low low
middle
66
O
F≤
T
＜
81
O
F
low middle high
T
≥81
O
F
middle high high
compressor
