Panasonic CS-25XKE Service Manual page 42

12.3.13 In Case of Reusing Existing Refrigerant Piping
Observe the followings to decide reusing the existing refrigerant piping.
-
Poor refrigerant piping could result in product failure.

In the circumstances listed below, do not reuse any refrigerant piping. Instead, make sure to install a new
piping.
Heat insulation is not provided for either liquid-side or gas-side piping or both.
o
The existing refrigerant pipe has been left in an open condition.
o
The diameter and thickness of the existing refrigerant piping does not meet the requirement.
o
The piping length and elevation does not meet the requirement.
o

Perform proper pump down before reuse piping.

In the circumstances listed below, clean it thoroughly before reuse.
Pump down operation cannot be performed for the existing air-conditioner.
o
The compressor has a failure history.
o
Oil color is darken. ( ASTM 4.0 and above ).
o
The existing air-conditioner is gas/oil heat pump type.
o

Do not reuse the flare to prevent gas leak. Make sure to install a new flare.

If there is a welded part on the existing refrigerant piping, conduct a gas leak check on the welded part.

Replace deteriorated heat insulating material with a new one.
Heat insulating material is required for both liquid-side and gas-side piping.
12.3.14 Proper Pump Down Method
1
Operate air
conditioner at
cooling mode for
10 ~ 15 minutes.
Most Important Process
Purpose: To make the oil
& refrigerant mix together.
They are in separated
condition when
air conditioner
is stopped.
2
After 10 ~ 15 minutes of pre
operation, close 2 way valve.
After 3 minutes, close 3 way
valve.
Mixed refrigerant &
oil will be collected
into outdoor unit.
42
3 4
Take out air
conditioner unit.
Only very small
amount of oil remain
inside piping, which
is acceptable.
Install New
Refrigerant air
conditioner.