Additional Refrigerant Charge - Westinghouse WHU09DHA21S Service Manual

Piping work and refrigerant charge
Air tight test
Do use nitrogen when performing air-tight test.
Connect the gauge manifold using charging hoses with a nitrogen cylinder to the check joints of
the liquid line and the gas line stop valves. Perform the air-tight test. Don't open the gas line stop
valves. Apply nitrogen gas pressure of 4.3MPa. Check for any gas leakage at the flare nut
connections, or brazed parts by gas leak detector or foaming agent. It is OK if gas pressure does
not decrease. After the air tight test, release nitrogen gas.

Additional refrigerant charge

Although refrigerant has been charged into this unit, additional refrigerant charge is
required according to the piping length.
The additional refrigerant precharge quantity should be determined and charged into the system
•
according to the following procedure.
Record the additional refrigerant quantity in order to facilitate maintenance and servicing activities.
•
Refrigerant charge before shipment (W0 (kg))
W0 is the outdoor unit refrigerant charge before shipment；
Xg is additional refrigerant outdoor unit needed to charge according to piping length during
installation.
Refrigerant
Model
precharged before
shipment (W0(oz/g))
9K
12K
18K
24K
36K
Procedure
Completion Applying
of Ref. Nitrogen
Piping Gas
of Leakage
Air tight procedure
0～24.6 ft
(0～7.5 m)
0g
33.5/0.95
0g
45.9/1.3
0g
56.44/1.6
0g
91.7/2.6
0g
111.2/3.15
Check of
Pressure Pass
Decrease
Repairing
Part
Total refrigerant pipe length
Longer than 24.6 ft (7.5 m)
Additional refrigerant charge=
(L-24.6)×0.161 oz/ft
Additional refrigerant charge=
(L-24.6)×0.376 oz/ft
- 21 -