Evacuation; Leak Check Of Connection Point - Panasonic MDF-DU702VH Service Manual

3．Evacuation

3.1 Leak check of connection point

Preparation: Leak check spray (liquid detergent may be used), dedicated GM, general
purpose GM *, powerful vacuum pump, Nitrogen cylinder, charge hose,
branching equipment, tools
* In case of evacuating simultaneously on the low temperature side and the
high temperature side
Procedure: Connect as shown below and prepare for vacuum evacuation. When repairing
on the low temperature side was also done, add general purpose GM and
connect. ← Vacuum exhaust at the same time at high temperature and low
temperature for shortening the time
(In the case of only the high temperature side, connect the hose from the
nitrogen cylinder directly to the refrigerant port)
Open the unopened valves of nitrogen cylinders, VR, VL, VH and general
purpose GM,
Perform a leak check of the connection point. (Nitrogen replacement: provided
that the secondary pressure is 0.5 to 0.7 MPa)
General GM
Nitrogen cylinder
Low temp.
低温側
Note： Use a leak check spray to check the gas leak at the connection point.
Generally, the explosion-proof vacuum pump has a small capacity, so prepare a
separate powerful vacuum pump.
(All flammable HC refrigerants are released, so there is no problem even if they are
not explosion-proof type)
Connection should be made surely without leakage.
Dedicated GM
Refrigerant
VR
port
VC
Vacuum
port
Charge hose
Valve sate
Explosion-proof
vacuum pump
VC
VG
VL
VH
VR
-44-
VH
VG
VL
Charge hose
Low pressure
service valve
High pressure
open shut
service valve
○
○
○
○
○
High pressure
service port
Low pressure
service port