Gree Ultra Heat GMV Multi VRF Heat Recovery Series Service Manual page 83

Ultra Heat GMV VRF Technical Service Manual_Heat Recovery Serial
for 1 hour. If the vacuum degree of -0.1 MPa cannot be reached, repeat this operation till water is
discharged.
(5) After vacuumization, turn off the regulator valve and keep for 1 hour. Ensure that the pressure
of the regulator valve does not increase.
2.2.2 Precautions
(1) Before vacuum pumping, make sure that outdoor unit's liquid valve, high pressure gas valve
and low pressure gas valve are completely closed. Use vacuum pump to extract air inside indoor unit
and connection pipe from the nozzles of liquid valve, high pressure gas valve and low pressure gas
valve of outdoor unit, as shown in follow figure.
(2) Because air extraction from outdoor unit's liquid valve, high pressure gas valve and low
pressure gas valve must be performed simultaneously, 2 sets of vacuum pump must be used at the
same time to guarantee the required vacuum degree.
(3) Turn off the valve before powering off the vacuum pump.
(4) Keep vacuuming for 2 hours. The vacuum meets the requirement if the pressure displayed by
the vacuum gauge does not increase.
(5) The units parallel connected to the module also need to be vacuumized.
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INSTALLATION