14
Indoor Unit
Installation
Pipe must be able to obtain the specified thickness and should be used with low
impurities.
Also when handling storage, pipe must be careful to prevent a fracture, deformity
and wound.
Should not be mixed with contaminations such as dust, moisture.
Plumbing materials and storage methods
Refrigerant piping on three principles
Drying Cleanliness
Airtight
Should be no moisture
inside
No dust inside.
There is no refrigerant
leakage
Items
Moisture
Dust
Leakage
Cause failure
- Significant hydrolysis of refrigerant oil
- Degradation of refrigerant oil
- Poor insulation of the compressor
- Do not cold and warm
- Clogging of EEV, Capillary
- Degradation of refrigerant oil
- Poor insulation of the compressor
- Do not cold and warm
- Clogging of EEV, Capillary
- Gas shortages
- Degradation of refrigerant oil
- Poor insulation of the compressor
- Do not cold and warm
Countermeas
ure
- No moisture in the pipe
- Until the connection is completed, the
plumbing pipe entrance should be
strictly controlled.
- Stop plumbing at rainy day.
- Pipe entrance should be taken side or
bottom.
- When removal burr after cutting pipe,
pipe entrance should be taken down.
- Pipe entrance should be fitted cap
when pass through the walls.
- No dust in the pipe.
- Until the connection is completed, the
plumbing pipe entrance should be
strictly controlled.
- Pipe entrance should be taken side or
bottom.
- When removal burr after cutting pipe,
pipe entrance should be taken down.
- Pipe entrance should be fitted cap
when pass through the walls.
- Airtightness test should be.
- Brazing operations to comply with stan-
dards.
- Flare to comply with standards.
- Flange connections to comply with
standards.
Nitrogen substitution method
Welding, as when heating without nitrogen substitution a large amount of the oxide film is formed on the internal piping.
The oxide film is a caused by clogging EEV, Capillary, oil hole of accumulator and suction hole of oil pump in compressor.
It prevents normal operation of the compressor.
In order to avoid this problem, Welding should be done after replacing air by nitrogen gas.
When welding plumbing pipe, the work is required.
◆
How to work
Regulator
Nitrogen gas
Pressure 0.02MPa less
Auxiliary valve
Taping
(Should not
contain air)
Welding Point
Oxide scale
Nitrogen
Note) should not block the outlet side.
When the internal pressure in pipe is above the
atmospheric pressure, pinhole is occurred and it
is a leakage cause.
