Precautions Concerning Piping Connection And Valve Operation - Mitsubishi Electric City Multi PUHY-P-THMU-A Installation Manual

10.2. Precautions concerning piping connec-
tion and valve operation
• Conduct piping connection and valve operation accurately and carefully.
• Removing the pinched connecting pipe
When shipped, a pinched connecting pipe is attached to the on-site liquid and
gas valves to prevent gas leakage.
Take the following steps 1 through 4 to remove the pinched connecting pipe
before connecting refrigerant pipes to the outdoor unit.
1 Check that the refrigerant service valve is fully closed (turned clockwise all
the way).
2 Connect a charging hose to the service port on the liquid/gas refrigerant
service valve, and extract the gas in the pipe section between the refriger-
ant service valve and the pinched connecting pipe (Tightening torque
12 N·m).
3 After vacuuming gas from the pinched connecting pipe, sever the pinched
connecting pipe at the location shown in [Fig.10.2.1] and drain the refriger-
ant.
4 After completing 2 and 3 heat the brazed section to remove the pinched
connecting pipe.
[Fig. 10.2.1]
B
< B >
< A >
C
A
E
D
<A> Refrigerant service valve (liquid side/brazed type)
<B> Refrigerant service valve (gas side/brazed type)
A Shaft
Fully closed at the factory, when connecting the piping, and when vacuuming.
Open fully after these operations are completed.
<When opening>
• Turn the shaft counterclockwise with a hexagonal wrench.
• Turn around the shaft until it stops.
<When closing>
• Turn the shaft clockwise with a hexagonal wrench.
• Turn around the shaft until it stops.
B Service port
Available for gas venting of the pinched connecting pipe, or vacuuming in the
refrigerant pipes on the site.
(Tightening torque 12 N·m)
C Cap
Remove the cap before operating the shaft. Be sure to return it to the original
position after completing the operation.
D Pinched connecting pipe severing portion
E Pinched connecting pipe brazing portion
1
No.
IDø25.4 [1]
C Shape
ODø25.4 [1]
2
No.
ODø9.52 [3/8]
C Shape
IDø15.88 [5/8]
1
PUHY-P72THMU-A
1
PUHY-P72YHMU-A
PUHY-P96THMU-A
1
PUHY-P96YHMU-A
PUHY-P120THMU-A
1
PUHY-P120YHMU-A
*1 P72, P96: Expand the liquid pipe (ID9.52 mm [3/8 in]) and connect directly to the valve. <field supply required>
3
ODø12.7 [1/2] ODø22.2 [7/8]
IDø25.4 [1]
IDø15.88 [5/8]
4
IDø9.52 [3/8]
ODø19.05 [3/4]
IDø25.4 [1]
ODø9.52 [3/8]
2 3 4
1
1 1
Warning:
• The section of the pipe on the unit between the two refrigerant service
valves is filled with gas. Extract the gas in the above-mentioned pipe
section before heating the brazed section to remove the refrigerant serv-
ice valve connecting pipe.
- If the brazed section is heated without first extracting the gas, the pipe may
burst or the connecting pipe may blow off causing serious injury.
Caution:
• Place a wet towel on the refrigerant service valve before heating the brazed
section to keep the temperature of the valve from exceeding 120 ˚C [248 ˚F].
• Direct the flame away from the wiring and metal sheets inside the unit to
prevent heat damage.
Caution:
• Do not vent R410A into the atmosphere.
• Refrigerant pipe connection
This product includes connecting pipes for front piping and bottom post-piping.
(Refer to [Fig.10.2.2])
Check the liquid/gas piping dimensions before connecting the refrigerant pipe.
Refer to item 9.2 Refrigerant piping system for piping dimensions.
Make sure that the refrigerant pipe is not touching other refrigerants pipes, unit
panels, or base plates.
Be sure to use non-oxidative brazing when connecting pipes.
<Refrigerant piping connection examples>
[Fig.10.2.2]
<A>
76
<C>
32
<C>
<A> Front pipe routing
<C> Included with outdoor unit
A Gas pipe (field supply required)
C Shape
(Unit: mm [in])
5 7
IDø15.88 [5/8]
ODø15.88 [5/8]
6
5 6 7
1
1 1
1 1
<B>
1
<C>
45
45
<C>
23
*1
A
B
A
B
<B> Bottom pipe routing
B
Liquid pipe (field supply required)
11
<C>
<C>