Mitsubishi Electric CITY MULTI PURY-P72ZKMU-A Manuel D'installation page 20

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.
9-5-1. Removing the pinched connecting pipes
When shipped, a pinched connecting pipe is attached to the on-site high-pressure and low-pressure 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 low-pressure/high-pressure 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 the figure below and drain
the refrigerant.
④ After completing ② and ③ heat the brazed section to remove the pinched connecting pipe.
P72,P96
<B> <A>
E
D
A
G
F
<A> Refrigerant service valve (low-pressure side/brazed type)
<B> Refrigerant service valve (high-pressure side/brazed type)
Ⓐ Shaft
Fully closed at the factory, when connecting the piping, and when vacuuming. Open fully after
these operations are completed.
<When opening>
<When closing>
Ⓑ Shaft
Fully closed at the factory, when connecting the piping, and when vacuuming.
Open fully after these operations are completed.
<When opening>
<When closing>
Ⓒ
Stopper pin
Prevents the shaft from turning 90°or more.
Ⓓ Service port
Available for gas venting of the pinched connecting pipe, or vacuuming in the refrigerant pipes
on the site.
Ⓔ
Cap
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
Ⓖ Pinched connecting pipe brazing portion
WT07828X01
P120,P144
D
<B> <A>
B
A
O S
C
D
E
G
F
GB-18