Gree GMV-PD100W/NAB-K, Service Manual

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DC Inverter Multi
VRF Service Manual
h. Repeat the above procedures on indoor unit B
i. After cleaning of liquid pipe, gas pipe shall be cleaned in the same way.
5.9 Pressure Maintaining and Leak Hunting
5.9.1 Pressure maintaining of refrigerant piping
After refrigerant piping of a system is welded,
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outdoor unit side.
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sealed.
Enter into the step of connection pipe pressure keeping and leak hunting
Operating Steps:
Locate and repair leakage
Finish
Check
pressure drop
Pressurization Complete the
installation of piping
Pressurization
Use nitrogen to add pressure from Freon nozzle of the gas and liquid pipe on outdoor unit side:
Step 1: Increase the pressure to 0.3MPa and wait for 3 minutes or longer
Step 2: Increase the pressure to 1.5MPa and wait for 3 minutes or longer
The step 1 and 2 are focused on checking the significant leakage point. If any, reweld immediately or
repair the leakage point.
Step 3: Increase the pressure to 2.5MPa and keep it for approx. 24 hours to check the small leakage.
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waiting time is too short. Therefore, the pressure in Step 3 must be kept for 24 hours.
Note: During pressure maintaining after nitrogen is filled, the pressure gauge shall not be dismantled,
because activities of dismantling or mounting pressure gauge would affect pressure change
Check pressure drop
Criteria for Inspection eligibility:
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), if
pressure drop is not more than 0.02MPa within 24h, the system will be eligible.
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; after 24 hours, when temperature becomes 25 ,
the system will be eligible if pressure is over 2.43 MPa and ineligible below 2.43 MPa.
If ineligible, leak sources must be located. After leak sources are found, re-welding or repair welding is
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pressure drop remains within required range.
Leak check
[Check 1] When pressure drop is found, leak hunting shall be performed in the ways as follows:
a. By ears…….to listen voices related to leakage
b. By hands……to sense whether leakage is existent at connecting parts
[Check 2] If no leakage is found using the above methods, nitrogen shall be discharged and refrigerant
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a. By soap and water……soap bubbles will show leakage positions if any.
b. Detector (such as halide detector) can be used for leak hunting.
Using the above methods, check all possible leak sources.
If leakage still fails to be located, sectional check shall be taken for refrigerant piping that would be divided
into multiple check portions for locating leak source in a certain section.