Cooper & Hunter CHV-5S224SNMX, Service Manual

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MAINTENACE 0 112 0
CHV
5 COM PACT MULTI VRF UNIT
SERVICE M ANUAL
5.1 System leak hunting
When refrigerant piping is to be installed, pressure maintaining and leak hunting is required for the piping.
After refrigerant piping is in connection with indoor unit and outdoor unit, pressure maintaining and leak hunting is
also required. The purpose of the test is to check whether any leak is existent at threaded connection of indoor unit
and outdoor unit and at new welded points.
Steps:
A. Fill the system pipeline with 20.0kgf/cm
2
Nitrogen
B. Check the main connections with soapy water, and mark it immediately if any leak.
C. After the detection is completed, fill the pipeline with 0.5±0.1kgf/cm2
（
relative pressure
）
Nitrogen. Repair
welding shall be performed immediately
D. After repair welding, Nitrogen is charged to reach 25.0kgf/cm
2
and remains at the pressure for 48h. After that,
check the reading of pressure gauge and the pressure drop calculated according to the following formula should not
be more than 1% of the test pressure. Otherwise, find out the reason and clear the leakage until eligibility is
reached.
ΔP=P1-P2
（
273+T1
）
/
（
273+T2
）
The fomula
： ΔP——Pressure drop （
MPa
）；
P1,P2——Pressure of nitrogen at the beginning and the end of experiment
（
MPa
）；
T1,T2——Temperature of nitrogen at the beginning and the end of experiment
（℃）。
5.2 Vacuum drying for the system
5.2Vacuum drying for the system
5.2.1 Selection requirement for the vaccum pump
Do not use different vacuum pump for vaccum-pumping for different refrigerant system
；
The final vacuum for the vacuum pump should reach -0.1Mpa;
The air discharge volume for the vacuum pump should reach 4L/S above;
The precision of vacuum pup should reach 0.02mmHg above;
The system vacuum pump for R410A must be with check valve
5.2.2 Operation procedure and notices for Vacuum drying