Special Functions; Control Logic; Defrosting Control; Compressor Control - Gree GWH12QB-K3DNA6O Service Manual

Service Manual

3. Special Functions

Defrosting Control

① Conditions for starting defrosting
After the time for defrosting is judged to be satisfied, if the temperature for defrosting is satisfied after detections for continuous 3minutes,
the defrosting operation will start.
② Conditions of finishing defrosting
The defrosting operation can exit when any of the conditions below is satisfied:
③ T ≥ (T – [T ];
outdoor pipe temperature outdoor ambient temperature temperature 1 of finishing defrosting
④ The continuous running time of defrosting reaches [tmax. defrosting time].

4. Control Logic

(1) Compressor Control

Start the compressor after starting cooling, heating, dehumidifying operations, and the outer fans start for 5s; When the machine is
shutdown, in safety stops and when switching to air-supplying mode, the compressor will stop immediately. In all modes: once the
compressor starts up, it will not be allowed to stop until having run for the [tmin. compressor running time] (Note: including cases of
shutdown when the temperature point is reached; except the cases requiring stopping the compressor such as fault protection, remote
shutdown, mode switching etc.); In all modes: once the compressor stops, it will be allowed be restart after 3-minute delay (Note: The indoor
units have a function of power memory, the machine can be restarted after remote shutdown and powering up again without delay).
1. Cooling mode
Start the machine to enter into cooling operation for cooling, the compressor is switched on.
2. Dehumidifying mode
Same as the cooling mode.
3. Air-supplying mode
The compressor is switched off.
4. Heating mode
(1) Start the machine to enter into heating operation for heating, the compressor is switched on.
(2) Defrosting:
a. Defrosting starts: the compressor is shut down, and restarts it after 55-second delay.
b. Defrosting ends: the compressor stops, then starts it after 55-second delay.
(2) Outer Fans Control
Notes:
Only the outer fans run for at least 80s in each air flow speed can the air flow be switched;
After the outer fans run compulsively in high speed for 80s when the machine starts up, control the air flow according to the logic.
After remote shutdown, safety stops, and when the machine stops after reaching the temperature point, as well as after the compressor
stops, extend 1 minute, the outer fans will stop (During the period in the 1 minute, the air flow of outer fans can be changed according to the
outdoor ambient temperature changes); When running with force, the outdoor fans shall run in the highest air flow.
(3) 4-way valve control
1. The 4-way valve control under the modes of Cooling, dehumidification and supplying air: closing;
2. The status of 4-way valve control under the heating mode: getting power;
(1) 4-way valve power control under heating mode
Starts the machine under heating mode, the 4-way valve will get power immediately.
(2) 4-way valve power turn-off control under heating mode
a. When you should turn off the power or switch to other mode under heating mode, the power of 4-way valve will be cut after 2 minutes of
the compressor stopped.
b. When all kinds of protection stops, the power of 4-way valve will be cut after delaying 4 minutes.
(3) Defrosting control under heating mode:
a. Defrosting begins: The power of 4-way valve will be cut after 50s of entering into the defrosting compressor.
b. Defrosting stops: The 4-way valve will get power after 50s of exiting the defrosting compressor.
(4) Evaporator frozen-preventing protection function
At the mode of Cooling, dehumidifying:
Evaporator frozen-preventing protection function is allowed to begin after 6 min of starting the compressor.
Technical Information
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