Precautions Concerning Piping Connection And Valve Operation - Mitsubishi Electric City Multi PURY-HP72TKMU-A-H Installation Manual

<Example>
Indoor 1:30 A: ø22.2 mm [7/8 in]
2:96 B: ø9.52 mm [3/8 in]
3:12 C: ø9.52 mm [3/8 in]
4:15 D: ø9.52 mm [3/8 in]
5:12 E: ø9.52 mm [3/8 in]
6:24 A1: ø19.05 mm [3/4 in]
A2: ø19.05 mm [3/4 in]
The total length of each liquid line is as follows:
ø22.2 mm [7/8 in]: A = 40 m [131 ft]
ø19.05 mm [3/4 in]: A1 + A2 = 4 m [14 ft]
ø9.52 mm [3/8 in]:B + C + D + E + a + b + f = 60 m [192 ft]
ø6.35 mm [1/4 in]:c + d + e = 20 m [64 ft]
Therefore,
<Calculation example>
Additional refrigerant charge
= 40 m [131 ft] × 0.21 kg/m [2.26 oz/ft] + 4 m [14 ft] × 0.14 kg/m [1.51 oz/ft] + 60 m [192 ft] × 0.054 kg/m [0.59 oz/ft] + 20 m [64 ft] × 0.021 kg/m [0.23 oz/ft] +
6 kg [212 oz] + 2 kg [71 oz] + 2 kg [71 oz] + 5 kg [177 oz] + 2 kg [71 oz]
= 29.7 kg [1048 oz]
10.2. Precautions concerning piping
connection and valve operation
When operating the service valves on the YKMU-H model of units, remove
the relay box by unscrewing the screws indicated with A in [Fig. 10.2.1].
Then, temporarily hook part B on part C using one of the unscrewed
screws. After the completion of valve operation, mount the relay box back on
and replace the wiring as they were. (Refer to [Fig.10.2.1])
[Fig. 10.2.1]
B
A
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 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 [Fig.10.2.2] and drain
the refrigerant.
4 After completing 2 and 3 heat the brazed section to remove the
pinched connecting pipe.
16
40 m [131 ft] a: ø9.52 mm [3/8 in] 10 m [32 ft]
10 m [32 ft] b: ø9.52 mm [3/8 in] 5 m [16 ft]
20 m [64 ft] c: ø6.35 mm [1/4 in] 5 m [16 ft]
5 m [16 ft] d: ø6.35 mm [1/4 in] 10 m [32 ft]
5 m [16 ft] e: ø6.35 mm [1/4 in] 5 m [16 ft]
3 m [10 ft] f : ø9.52 mm [3/8 in] 5 m [16 ft]
1 m [4 ft]
C
At the
conditions
below:
[Fig. 10.2.2]
P72,P96
<B> <A>
C
B
A
E
D
<A> Refrigerant service valve (low-pressure side/brazed type)
<B> Refrigerant service valve (high-pressure 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>
<When closing>
B
Service port
Available for gas venting of the pinched connecting pipe, or vacuuming in the
refrigerant pipes on the site.
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
Warning:
The sections between the refrigerant service valves and the pinched
and refrigerant oil in the above-mentioned pipe section before heating
the brazed section to remove the refrigerant service valve pinched
connecting pipe.
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
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.10.2.3])
Check the high-pressure/low-pressure piping dimensions before connecting
the refrigerant pipe.
Refer to the table on the next page 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.
].