Precautions Concerning Piping Connection And Valve Operation - Mitsubishi Electric City Multi PUHY-P72TKMU-A Installation Manual

10.2. Precautions concerning piping
connection 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
refrigerant service valve and the pinched connecting pipe.
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 refrigerant.
4 After completing 2 and 3 heat the brazed section to remove the
pinched connecting pipe.
[Fig. 10.2.1]
• P72, 96
<A> <B>
D
A
E
G
F
<A> Refrigerant service valve (liquid side/brazed type)
<B> Refrigerant service valve (gas side/brazed type)
Shaft
A
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.
Shaft
B
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.
• Turn around the shaft until it stops.
<When closing>
• Turn the shaft clockwise.
• Turn around the shaft until it stops.
Stopper pin
C
Prevents the shaft from turning 90˚ or more.
Service port
D
Available for gas venting of the pinched connecting pipe, or vacuuming in the
refrigerant pipes on the site.
Cap
E
Remove the cap before operating the shaft. Be sure to return it to the original
position after completing the operation.
Pinched connecting pipe severing portion
F
Pinched connecting pipe brazing portion
G
14
• P120, 144
<A> <B>
D
A
E B
O S
G
C
D
F
Warning:
• The sections between the refrigerant service valves and the pinched
connecting pipes are filled with gas and refrigerant oil. Extract the gas
and refrigerant oil in the above-mentioned pipe section before heating
the brazed section to remove the refrigerant service valve pinched
connecting pipe.
- If the brazed section is heated without first extracting the gas and
refrigerant oil, the pipe may burst or the pinched connecting pipe may blow
off and ignite the refrigerant oil, 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 needs 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 the table below 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.
Be careful not to burn the wiring and plate when brazing.
<Refrigerant piping connection examples>
[Fig.10.2.2]
<A>
<C> <D>
A
B
C
D
E
F
<A> Front pipe routing
<C> Liquid side
Refrigerant service valve piping
A
B On-site piping (Adjust the pipe's position to the knockout hole.)
Elbow
C
D Reducer etc.
On-site piping (gas connecting pipe)
E
F On-site piping (liquid connecting pipe)
Diameter
Model Refrigerant pipe
Liquid
P72 ø9.52 [3/8] Brazed *1
ø22.2 [7/8]
ø9.52 [3/8] Brazed *1
P96
(ø12.7 [1/2] Brazed) *2, *4
ø9.52 [3/8] Brazed *2
P120 ø28.58 [1-1/8]
(ø12.7 [1/2] Brazed) *1, *3, *5
P144 ø12.7 [1/2] Brazed *1
*1 Expand the on-site piping and connect to the refrigerant service valve piping.
*2 Use the pipe joint (field supply) and connect to the refrigerant service valve
piping.
*3 In the case the unit is used in combination with other outdoor units.
*4 Furthest piping length (OU from IU) 90 m [295 ft]
*5 Furthest piping length (OU from IU) 40 m [131 ft]
<B>
<C> <D>
A
D
E
F
<B> Bottom pipe routing
<D> Gas side
(Unit: mm [in])
Service valve
Gas Liquid Gas
ø9.52
Brazed *2 [3/8]
ø28.58
[1-1/8]
ø12.7
Brazed *2 [1/2]