Piping Insulation - Panasonic CS-VU9SKQ Service Manual

11.3.5

Piping Insulation

1. Please carry out insulation at pipe connection portion as mentioned in Indoor/Outdoor Unit Installation Diagram.
Please wrap the insulated piping end to prevent water from going inside the piping.
2. If drain hose or connecting piping is in the room (where dew may form), please increase the insulation by using
POLY-E FOAM with thickness 6 mm or above.
Pump Down Method When Reuse Existing Piping (R22 Model) for R32 Model
Compressor oil of R22 model is insoluble in compressor oil of R32 model.
The mixing of compressor oil may cause damage of compressor.
Possibility of Mixing
■ Reuse of piping of R22 model is dangerous because of
its compressor oil.
■ Reuse the piping of R22 model only when it is
unavoidable, eg. concealed piping.
■ When reuse piping of R22 model, pump down must
be carried out properly to ensure compressor oil which
is remained inside piping is collected away.
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.
In case pump down cannot be done, please flush the piping using R32 refrigerant.
Mixed refrigerant
& oil will be
collected into
outdoor unit.
Must do re-flare of pipes before connecting to units.
To Reuse Old Piping
■ Piping of R22 model can be reused only when
air-conditioner is properly pumped down.
■ The purpose of pump down is to collect back the
compressor oil (which is mixed with refrigerant and
circulating inside refrigeration cycle) properly into the
outdoor unit of air conditioner.
3. Take out air conditioner unit.
4. Install New Refrigerant air conditioner.
43
Only very small
amount of oil remain
inside piping, which
is acceptable.