Piping Connections And Valve Operations - Mitsubishi Electric CITY MULTI PUHY-P72TNU-A-B Manuel D'installation

Pipes a,b,c,d,e
Capacity index of indoor unit
05, 06, 08, 12, 15, 18
24, 27, 30, 36, 48, 54
72
96

9-5. Piping connections and valve operations

Before heating the brazed sections, remove the gas and oil that are trapped in the pipes.
- Failure to do so may generate fire, resulting in serious injury.
Ventilate the room while servicing the unit.
- If the refrigerant leaks, oxygen deficiency may result. If the leaked refrigerant comes in contact
with a heat source, toxic gas will be generated.
Store pipes indoors, and keep both ends of the pipes sealed until just before making a
flare connection or brazing. (Store elbows and other joints in plastic bags.)
- If dust, dirt, or water enters the refrigerant lines, the refrigerant oil will deteriorate and the
compressor will malfunction.
Keep the service valves closed until refrigerant charging is completed.
- Failure to do so will damage the unit.
Place a wet towel on the service valves before brazing the pipes to keep the temperature of
the valves from rising above 120ºC (248ºF).
- Failure to do so may result in equipment damage.
Keep the flame out of contact with the cables and metal sheet when brazing the pipes.
- Failure to do so may result in burnout or malfunction.
Braze the pipes with a nitrogen purge to avoid oxidation.
- Oxidized flux inside the refrigerant pipes will cause the refrigerant oil to deteriorate and cause
the compressor to malfunction.
WT09452X01
[mm (in)]
Pipe
Liquid Gas
ø6.35 (ø1/4) ø12.7 (ø1/2)
ø9.52 (ø3/8) ø15.88 (ø5/8)
ø9.52 (ø3/8) ø19.05 (ø3/4)
ø9.52 (ø3/8) ø22.2 (ø7/8)
GB-30