Nitrogen Charge Before Nitrogen Blowdown; Nitrogen Blow - Panasonic MDF-DU702VH Service Manual

1.6 Nitrogen charge before nitrogen blowdown

procedure ：After 1.5 , VC, VG are shut, VR, VH, VL are opened and nitrogen is charged
(about 30 seconds) (however, the secondary pressure is 0.5-0.7 MPa)
note：In order to prevent air from entering the freezing circuit, fill with nitrogen.

1.7 Nitrogen blow

Procedure：Once all the valves are shut, reconnect as shown below and blow nitrogen for about
30 seconds into the circuit. (Nitrogen replacement: provided that the secondary
pressure is 0.5 to 0.7 MPa)
Caution! Since the refrigerant may burn with the flame of the welding machine, always carry out
the above procedure.
Charge hose
Nitrogen cylinder
Long hose
Explosion-proof
vacuum pump
Note：Nitrogen blow is performed to completely release the refrigerant. The flow rate of nitrogen
may be small (to the extent that it feels a little with the skin).
Valve state
open
VC
VG
○
VL
○
VH
○
VR
Dedicated GM
Refrigerant
port
VR
VC
VG
Vacuum
port
Valve state
open shut
○
VC
○
VG
○
VL
○
VH
○
VR
-41-
shut
○
○
High pressure port
VH
Low pressure
VL
port
Low pressure side
service pipe
Piercing tool
outdoor
Charge hose