Heating Mode; Defrosting - GREE ELECTRIC GUHD09NK3CO Service Manual

U-Match Series DC
Inverter Service Manual

2.3 Heating Mode

When the heating command is sent out, it is started to calculate the system load demand value. If the load is 0, all
started. After 30 seconds, the compressor will increase its frequency to the required initial frequency 40Hz before it started.
It is started to count the time when the compressor frequency is increased to 20Hz. After 10 seconds, the 4-way valve is
energized and then the indoor fan will run as per cold air prevention mode. The compressor will keep running at initial
frequency for 3 minutes. After that, the compressor, EXV and outdoor fan will adjust according to logic.

2.4 Defrosting

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