Air Conditioner Service Manual
7
seconds since the stop of compressor.
2) Auto fan control (heating)
In heating mode (include in “I feel” mode) , fan speed is determined by
δ
t
as the following:
(3) 4-way valve control
In heating mode, 4-way valve will power on ahead of compressor for 5 seconds, and cut off
for 2 minutes later than compressor. 4-way valve will not power off unless the machine to be
switched off, mode changed or on the process of defrosting.
(4) Defrosting
Defrosting is controlled by the microprocessor.
When one of the following conditions is satisfied, unit comes into defrosting:
a. Outdoor heat exchanger Temperature (OPT) is continuously less than 3
℃
while the unit runs
for more than 40 minutes, and OPT is keeping under -6
℃
for more than 3 minutes.
b. Outdoor heat exchanger Temperature (OPT) is continuously less than 3
℃
meanwhile the
unit runs for more than 80 minutes, and OPT is keeping under -4
℃
for more than 3
minutes.
c. Outdoor heat exchanger Temperature (OPT) is continuously less than 3
℃
while the unit runs
for more than 120 minutes, and OPT is keeping below -2
℃
for more than 3 minutes.
Before the air con comes into defrosting, compressor running frequency drop down to a
lower frequency firstly, then the compressor shuts down.
In defrosting, the max. frequency of compressor is F9 (a little less than the highest
frequency ). In this period all protection function are available.
In defrosting, LED showing by winking.
No matter what AC come into or out of defrosting, indoor fan motor speed is the same as Cold
Air Prevention Control.
While one of the following conditions is satisfied, unit comes out of defrosting and shifts to
heating mode:
a. Outdoor coil Temperature (OPT)
≥
15
℃.
b. The time of defrosting keeps for more than 10 minutes.
(5) Indoor exchanger overheat protection
When Indoor exchanger Temperature (IPT) is higher than 55
℃
,
unit comes into indoor exchanger
RT
‐
ST
δ
t come down
δ
t come up
℃
3.5
3.0
1.5
1.0
High fan
Min fan
Low fan
3.5
1.5
Compressor
ON
OFF
ON
OFF
ON
OFF
NORMAL
800
4-way valve
Expansion valve
Outdoor fan motor
50S
Defrosting time ≤
10Mins 15S 15S
10S