Gree Ultra Heat GMV-VQ72W/A-F, Service Manual, Page: 160 / 207

Ultra Heat GMV VRF Technical Service Manual_Heat Recovery Serial MAINTENANCE
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Note: Compressor lubricant must be kept completely airtight. GREE compressors use special
lubricant FV50S whose moisture absorption capability is high. Requirements on air-tightness of these
compressors are higher.
(2) Prepare other materials.
1) Prepare enough nitrogen. They will be used during welding. Nitrogen pressure should be 2.0 MPa
at least.
2) Prepare welding rods. In addition to ordinary welding rods, you should also prepare special
welding rods (containing 5% or more silver). Compressors inlets and outlets are made of copper plated
steels, which require special welding rods and materials.
3) Prepare gases for welding. Oxygen and acetylene of proper amount should be determined with
consideration of actual welding positions. Try to finish the welding task once. Avoid repeated welding.
4) Prepare tools, including hexagon, diagonal pliers, combination pliers, needle nose pliers,
multimeter, pressure gauge, Phillips screwdriver, flathead screwdriver, wrenches (at least two), PVC
insulation tape, and tielines (multiple).
Step 8: Install a new gas/liquid separator.
Note: If a faulty compressor needs replacement, the gas/liquid separator needs replacement as well.
This is to avoid abnormality from happening inside the gas/liquid separator, and affecting system safety
and reliability.
Put the gas/liquid separator on a chassis and connect the inlet pipe of the gas/liquid separator with
the outlet pipe. Then, connect the pipe to a nitrogen source. The nitrogen source can be connected
based on actual situation, for example, you can add a bypass interface or directly connect the nitrogen
source to the inlet/outlet pipe. If the pipe is big, cover it with tape as well. Make sure nitrogen can
smoothly flow through the gas separator.