Service manual

The indoor unit displays “H1”
c) Oil-returned nished condition in heating mode
The duration reaches 5min
2.1.4 Fan Mode
The compressor, the outdoor fan and the 4-way valve are closed; temperature setting range is 16
～
30
℃
.
2�2 Protection Function
2.2.1 Mode Conict Protection of indoor unit
When the setting mode is different of different indoor unit, the unit runs in below status:
a. The mode of the rst operating indoor unit is the basic mode, then compare the mode of the other indoor units to
see if there is a conict. Cooling mode (dry mode) is in conict with heating mode.
b. Fan mode is in conict with heating mode and the heating mode is the basic mode. No matter which indoor unit
operates rst, the unit will run in heating mode.
2.2.2 Overload Protection Function
When the tube temperature is a little low, the compressor raises the operation frequency; when the tube temperature is
a little high, the compressor frequency is restricted or lows down the operation frequency; when the tube temperature is too
high, the compressor protection stops running. If the discharge temperature protection continuously appears for 6 times, the
compressor can’t resume running. The compressor can resume running after cutting off the power and then putting through
the power. (if the running time of the compressor is longer than 7min, the protection times record will be cleared)
2.2.3 Discharge Protection Function
When the discharge temperature is a little low, the compressor raises the operation frequency; when the discharge
temperature is a little high, the compressor frequency is restricted or lows down the operation frequency; when the
discharge temperature is too high, the compressor protection stops running. If the discharge temperature protection
continuously appears for 6 times, the compressor can’t resume running. The compressor can resume running after cutting
off the power and then putting through the power. (if the running time of the compressor is longer than 7min, the protection
times record will be cleared)
2.2.4 Communication malfunction
Detection of the quantity of installed indoor units: After 3min of energizing, if the outdoor unit does not receive the
communication data of certain indoor unit, the outdoor unit will judge that indoor unit is not installed and will treat it as it
is not installed. If the outdoor unit receives the communication data of that indoor unit later, the outdoor unit will treat that
unit as it is installed.
2.2.5 Compressor high-pressure protection
a. When the high-pressure switch is detected cut off for 3s continuously, the compressor will enter high-pressure
protection as it stops when reaching set temperature. Meanwhile, the outdoor unit will send the signal of “high-pressure
protection” to the indoor units;
b. After the appearance of high-pressure protection, when the high-pressure switch is detected closed for 6s
continuously twice an hour, the compressor can resume running only after cutting off the power and then putting through
the power.
2.2.6 Compressor low-pressure protection
a. Low Pressure Protection for Shutdown
After the compressor stops for ve minutes, if it is detected that the low pressure protection switch is opened, then a
low pressure protection signal will be send out.
If it is detected continuously for three seconds that the low pressure protection switch is opened after the compressor
stops for less than five minutes, then a low pressure protection signal will be send out. However, if the low pressure
protection occurs twice in one hour, then it becomes unrecoverable and has to be recovered by powering the outdoor unit
again.
b. Low Pressure Protection during the Operation
a) When it is detected continuously for three seconds that the low pressure protection switch is opened, then the
whole unit should be shut off and a low pressure protection signal should be sent to the indoor unit.
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