Mitsubishi Electronics PUHY-YMC Precautions concerning piping connection and valve operation

10.3. Precautions concerning piping connection and valve operation

<For variable capacity unit>	<When shipped from	^	<After installation>
• Connect piping and operate valves exactly as described in the figure below.	the manufacturer>

•After performing the following distributor (gas) connection, remove the con- necting pipe included with the gas ball valve of the variable capacity unit, and mount the distributor (gas) (optional).

1When brazing the distributor (gas), braze it outside of the unit before mount- ing on the variable capacity unit.

2During 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.

3The refrigerant circuit is closed with a round, close-packed packing at the

shipment to prevent gas leak between flanges. As no operation can be done under this state, be sure replace the packing with the hollow packing attached at the piping connection.

4At 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.

A	S
O
3

1

1 B

1

3

•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.

• Connect ball valve piping in the order of (oil balance) → (liquid side) →	(gas side).
Ball valve	Ball valve
	(gas side)
(liquid side)	E
E
			A
Ball valve
(oil balance side)
E
	O	S	B

F

C

ENGLISH

O S

O S

G

ø 15.88

To distributor (liquid)

ø 12.7

H

To constant capacity unit

I

D

ø 28.6

J

(Figure shows valve fully open.)

Warning:

Braze the distributor (gas) outside the unit, before mounting distributor (gas)* to ball valve of the variable capacity 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.

15