Vacuum Evacuation Of Cooling Circuits; Vacuum Evacuation Before Nitrogen Blowing - Panasonic MDF-DU702VH Service Manual

1.4 Vacuum evacuation of cooling circuits

preparation ：Explosion-proof vacuum pump, detector for HC refrigerant
procedure：Since the refrigerant is dissolved in the compressor oil, connect the explosion-proof
vacuum pump to the tip of the long hose led outdoors, and perform vacuum
evacuation from the refrigeration circuit for at least 10 minutes. (Place vacuum pump
outdoors)
When no gas is detected, shut all the valves and stop the pump.
Note： Apply a detector to the exhaust port of the vacuum pump to confirm that the refrigerant
has been released.

1.5 Vacuum evacuation before nitrogen blowing

Preparation ：Nitrogen cylinder, pressure regulator, charge hose, branching instruments, tools,
leak check spray (liquid detergent can also be substituted)
Procedure：Connect the nitrogen cylinder as shown below and operate the explosion-proof
vacuum pump. Open the valves VC, VG, VR and perform vacuum evacuation
between the nitrogen cylinder and the dedicated GM.(About 1 minute)
Charge hose
Nitrogen cylinder
Long hose
Explosion-proof
vacuum pump
Note：make sure connection is not leaky.
Long hose
Dedicated GM
Refrigerant
port
VR
VC
VG
Vacuum
port
Valve state
open shut
○
VC
○
VG
○
VL
○
VH
○
VR
-40-
Placement
Outdoor
Exhaust for
outdoor
High pressure port
VH
Low pressure
VL
port
Low pressure side
service pipe
Piercing tool
Charge hose
High pressure side
service pipe