Mitsubishi Electric CITY MULTI PUHY-YMC Installation Manual page 16

<For constant capacity unit>
• Connect piping and operate valves exactly as described in the figure below.
• Gas side connecting piping is already assembled when the equipment is shipped. (See figure
on right.)
1 When brazing to connecting pipe with flange, remove the connecting pipe with flange from
the ball valve, and braze at the outside of the unit.
2 During the time when removing the connecting pipe with flange, remove the seal attached
on the back side of this sheet and paste it onto the flange surface of the ball valve to prevent
the entry of dust into the valve.
3 The refrigerant circuit is closed with a round, close-packed packing at the shipment to pre-
vent gas leak between flanges. As no operation can be done under this state, be sure re-
place the packing with the hollow packing attached at the piping connection.
4 At the mounting of the hollow packing, wipe off dust attached on the flange sheet surface
and the packing. Coat refrigerating machine oil onto both surfaces of the packing.
• After evacuation and refrigerant charge, ensure that the handle is fully open. If operating with the valve closed, abnormal pressure will be imparted
to the high- or low-pressure side of the refrigerant circuit, or a shortage of oil in the compressor may occur due to lack of oil flow between units, giving
damage to the compressor, four-way valve, etc.
• For evacuating, be sure to provide an oil balance pipe between the variable capacity and constant capacity units.
• Determine the amount of additional refrigerant charge by using the formula, and charge refrigerant additionally through the service port after
completing piping connection work.
• After completing work, shut the service port and cap tightly so that gas leaking does not occur.
Ball valve
(Gas side)
C
D'
To distributor (gas) inside
variable capacity unit
(Figure shows valve fully open.)
Warning:
Be sure to remove the connecting pipe from the ball valve, and braze it outside the unit.
- If brazed while mounted, the ball valve is heated and could result in cracking or gas leaks. The wiring inside the unit could also be burned.
16
Ball valve
(Liquid side)
MP35K
ø12. 7
G
To distributor
(liquid)
ø28.6
Ball valve
(Oil balance side)
A
F
B
ø12.7
H'
To variable capacity unit
Replace the solid packing.
3
1
Hollow packing
The unit is set vertically between
the compressor and control box.
Fastening plate