Gree Ultra Heat GMV-VQ72W/A-F, Service Manual, Page: 165 / 207

Ultra Heat GMV VRF Technical Service Manual_Heat Recovery Serial MAINTENANCE
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Install the electric box and connect various parts to the electric box by referring to the marks made
beforehand and the wiring diagram on the back of the box. Wire the compressors and corresponding
electric heating belts.
Note: Wires should be checked against the wiring diagram beforehand so that they can be
connected correctly.
Step 16: Start for debugging.
Start the units and set them to run in refrigerating full-start, refrigerating single-start, heating full-start,
and heating single-start modes respectively. Duration for each running mode should be 30 minutes at
least. After the debug, analyze data and adjust the unit system, to ensure indexes of the entire system.
For details about each index, please consult after-sale persons and technicians.
3 CAUTIONS ON COMPRESSOR DRIVE BOARD AND PFC BOARD
REPLACEMENT
(1) Disconnect the power supply of the system. Set a multimeter to the AC voltage gear and
measure voltage between two of the lines (L1, L2, L3, and N). The measuring result should be 0 V
(sometimes, multimeters may be faulty and read false values). Set a mark beside the power supply for
warning.
(2) Measure compressor drive DC bus voltage between two wire terminals of P, U, V, W and N.
Set the multimeter to the DC voltage gear and measure the voltage between P and N. The voltage
should be lower than 36 V. If no multimeter is available, wait for 20 minutes before performing the steps
below.
PFC board