Gree Ultra Heat GMV Multi VRF Heat Recovery Series Service Manual page 103

Ultra Heat GMV VRF Technical Service Manual_Heat Recovery Serial
(2) Check system refrigerants before startup
Before the system is started, connect the liquid-tube valve of ODU with a high pressure gauge and
the gas-tube valve of ODU with a low pressure gauge, and then read their values. In this case, high
pressure and low pressure of the system should be in balance status, and the difference between the
saturation temperature corresponding to the balanced pressure value and the environment temperature
(the higher in outdoor and indoor temperatures is taken as environment temperature) should not be
larger than 5° CK. If the difference is larger than 5° C K, it is required to check the ODU for leakage.
NOTE: Guarantee that the system has never been started before this test. Otherwise, the high
pressure value will be over-higher than the environment temperature or the low pressure value will be
over-lower than the environment temperature.
Example:
The outdoor environment temperature is 30° C (86℉) and the indoor environment temperature is
28° C (82℉). The pressure gauges connected with the system show that the high pressure value is 28° C
(82℉) and the low pressure value is 27° C (81℉). The difference between the outdoor environment
temperature and either pressure value is less than 5° C K. It indicates that the system standby pressure
is normal.
3.2.3 Electrical system check
(1) Check for high electromagnetic interference, dusts, and acidic or alkaline gas in the unit
environment.
1) The air conditioning unit can neither share the same power supply system with the equipment
containing variable-frequency drives, nor reside near the equipment generating high electromagnetic
interference. Otherwise, the air conditioning unit may fail to properly work due to interference. If this case
exists, records should be made. In the case of serious influence, the air conditioning unit must be
relocated or relevant measures must be taken.
2) Prevent acidic or alkaline gas/liquid from rusting cables of the air conditioning unit.
(2) Check the installation appearance of power cables.
Check whether power cables of indoor and ODUs are installed according to vendor requirements
and whether cable connectors are reliably connected. Except the connection part of patch panels, wire
exposure is not allowed on any connection part of power cables.
(3) Check the power capacity required for the unit.
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