Gree GC201808-III, Service Manual

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GREE GMV5 HR HEAT RECOVERY UNITS
305
Cautions on replacement of compressors:
①
Before installing new compressors, remove the sealing rubbers and weld the compressors with
corresponding pipes. During welding, charge nitrogen into the pip
es. Since compressors’
suction and discharge pipes are made of copper plated steels, you need to prepare special
welding rods (containing 5% or more silver). Welding clearance should be controlled within
0.1~0.3mm (0.0039inch~0.0118inch), avoiding blockage or loose welding. During welding,
control pipe openings from being over-heated.
②
After the pipeline system is welded, use special supports and bolts to fix the compressors,
ensuring stability of the compressors during running.
③
Power lines of the compressors should be wired following the factory installation. You can refer
to the wiring diagram. Phase sequence error and inverse connection of compressors are not
allowed. In particular, if there are two inverter compressors GMV-Q120WM/B-F(U) that need
replacement, pay attention to wiring. Control varies with compressors. Inverse connection of
the compressors may cause damage to units.
Step 11: System check.
(1) Check welding joints for abnormalities.
(2) Charge nitrogen into the system for leakage detection. If you are maintaining ODUs and the
IDU system is normal, you can charge nitrogen into the ODU system only. Note that nitrogen
should be charged from both the high pressure side and low pressure side. You are advised to
charge through all valves. Nitrogen pressure should be larger than 20 kgf. Then, charge
soapsuds into the system and check specially the weld joints for leakage.
(3) Finally, charge nitrogen into the system again for pressure check. Close all valves and keep
system pressure up to 25 kgf for more than 12 hours. If the pressure remains unchanged, you
can extract all air. Otherwise, you should find the leakage points first.
While determining system pressure change, take temperature into consideration. For 1°C
temperature change, pressure will change by 0.01MPa(1.45PSIG) accordingly. Suppose that nitrogen
pressure reaches 2.5MPa(363PSIG) at 30°C(86°F), 12 hours later, temperature decreases to 25°C(77°F)
and pressure decreases to 2.43MPa(352PSIG) accordingly. The system is regarded qualified despite
the pressure decrease.
Step 12: Fill lubricant.
Quantity of lubricant that is needed is subject to the total draw amount from compressors and parts.
The fill amount should be equivalent to the draw amount. If the draw amount is too little or too much,
clear all lubricant first and determine fill amount by referring to Appendix 1 (accessory list).
Fill amount is determined by two factors: the number of compressors replaced and the draw amount
from each part. For replacement of one compressor, 1.5 L lubricant should be added. The fill amount
should be equal to or a little larger than the draw amount.
Examples:
For GMV-Q120WM/B-F(U) units, one compressor is replaced; lubricant that is drawn from the gas
separator is 1L and lubricant that is drawn from the oil separator is 0.7L.Then, the total required amount
is 1.5L+1L+0.7L=3.2L. You should add 3.2L lubricant into the system.