Haier AB422XCBAA Service Manual page 130

Changing from heating mode to cooling mode, 3 minutes later, it is shut off.
E. In heating mode, when indoor temperature has arrived the set one (sensor is OFF),
4-way valve will be shut off 3 minutes later.
8.2.1.4 Solenoid valve control
Cooling mode: After the outdoor unit receives the Startup signal from indoor unit, the
corresponding solenoid valve will open 10 seconds earlier than compressor startup.
Heating mode: After the outdoor unit receives the Startup signal from indoor unit, all the
solenoid valve of the corresponding system will open 10 seconds earlier than compressor
startup.
After the compressor shuts off, the solenoid valvs will close 3 minutes later.
8.2.1.5 Unloading valve control
When only one indoor unit of one system starts up, the solenoid valve will open.
When receiving the overheating signal from indoor unit, solenoid valve will open.
If one system only connects one indoor unit (single type), solenoid valve will open.
If two indoor units of one system are running, and ourdoor ambient temperature is no
more than –2 degree, the solenoid valve will open.
Priority of operation modes:
All indoor units are running in the same mode:
1) Operate as "prior to the earlier entering", the outdoor will adjust if there is
non-matching type and inform of indoor units which is entering later.
2) When there is non-matching, the indoor unit entering later will act: the indoor buzzer
sounds two times, and then the indoor unit is in standby state.
3) Method to eliminate the non-matching type
a) The operation mode of indoor unit entering later changes to the same mode of
the one earlier.
b) The operation mode of indoor unit entering later changes to FAN mode.
c) The operation mode of indoor unit entering earlier stops or changes the mode.
d) The operation mode of indoor unit entering later stops.
8.2.2 Protection functions
Protection functions of the system can be controlled individually.
8.2.2.1 Overheating protection
If the units of the two systems are all operating, when the four indoor units all reach the
stop-motor point of the overheating protection, outdoor motor can stop. Outdoor motor has
not the control point of High/Med/Low speed. If one indoor unit reaches the
stop-compressor point of overheating protection, the corresponding compressor will stop,
but the outdoor motor and the other system will work normally. If the two systems all
arrives at the stop-compressor point of overheating protection, the outdoor unit stops; at
this time, if one system resumes, the outdoor motor and the system will work normally, the
compressor not resuming will stop.
8.2.2.2 3-minute protection when compressor starts up
If the compressor stops running, it must 3 minutes later that it can re-start up; if the unit is
powered off during operation within 3 minutes, after being powered on, 3 minutes later, the
compressor can start up again.
8.2.2.3 Communication abnormal between indoor and outdoor
Within 4 minutes after outdoor unit is powered on, it cannnot communicate with indoor unit,
or in the couse of communication, it cannot communicate with indoor unit for 4 minutes
contineously, then the outdoor stops running and shows failure code. After the
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