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PIPING WORK AND REFRIGERANT CHARGE
8.5 VACUUMING
Connect a manifold gauge and vacuum pump to the check joints.
8.5.1
If the penetration of moisture is suspected, perform "Triple
Evacuation Method" that is described in the next paragraph.
1 Vacuum until the pressure reaches 500 microns (0.5 mmHg)
or Lower for two hours.
2 After vacuum pumping work, stop the vacuum pumping and
leave the gauge for one hour.
3 Check to ensure that the pressure in the vacuum gauge
does not increase.
8.5.2
According to the following [Step 1] [Step 2] [Step 3] in order,
conduct vacuum drying work.
Step 1
1 Vacuum until the pressure reaches 2000 microns
(2.0 mmHg).
2 Pressurize with nitrogen up to 0.3 MPaG (50 PSIG) for
15 minutes.
3 Release pressure until reaching the atmosphere level, as low
as 0.03 MPaG (5 PSIG).
Step 2
1 Vacuum until the pressure reaches 1000 microns
(1.0 mmHg).
2 Pressurize with nitrogen up to 0.3 MPaG (50 PSIG) for
15 minutes.
8.6 ADDITIONAL REFRIGERANT CHARGE CALCULATION
Although refrigerant has been charged into this unit in advance, additional refrigerant charge is required according to piping length.
Determine the additional refrigerant quantity according to the following procedure, and charge the system with it.
Record the additional refrigerant quantity to facilitate maintenance and servicing activities thereafter.
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PMML0479 rev.2 - 02/2018
High/low pressure gas stop valve
Heat pump system
Liquid stop valve
High/low pressure gas stop valve
Heat recovery system
Low pressure gas stop valve
Liquid stop valve
4
torque after the vacuum drying work.
5 If the pressure inside the gauge does not reach 500 microns,
it is considered that there is gas leakage.
6 Check for any gas leakage once again.
7 If no leakage exists, it might be moisture remains inside the
pipes. Perform "Triple Evacuation Method".
3 Release pressure until reaching the atmosphere level, as low
as 0.03 MPaG (5 PSIG).
Step 3
1 Vacuum until the pressure reaches 500 microns (0.5 mmHg).
2 Stop vacuum pump.
3 Check that the vacuum 500 microns (0.5 mmHG) can
maintain for one hour.
N O T E
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