Drainage Piping Work - Mitsubishi Electric City Multi PUMY-P250YBM Installation Manual

4. Installing the refrigerant piping
A
Fig. 4-14
Fig. 4-15
5. Drainage piping work
Outdoor unit drainage pipe connection
When drain piping is necessary, use the drain socket or the drain pan (option).
Drain socket
Drain pan
E F
G
H
I
B
HI
LO
K
C D
* The figure to the left is an example only.
The stop valve shape, service port
position, etc., may vary according to the
model.
* Turn section A only.
(Do not further tighten sections A and
B together.)
C Charge hose
D Service port
PAC-SK27DS-E
PAC-SJ83DP-E
4.6. Refrigerant pipe airtight testing method
Airtight test (Fig. 4-14)
Airtight test should be made by pressurizing nitrogen gas. For the test method, refer
to the following figure.
(1) Connecting the testing tool. Make a test with the stop valve closed. Be also sure
to pressurize both liquid or high-pressure pipe and gas or low pressure pipe.
(2) D o not add pressure to the specified pressure all at once; add pressure little by
little.
1 Pressurize to 0.5 MPa, wait 5 minutes, and make sure the pressure does not
decrease.
2 Pressurize to 1.5 MPa, wait 5 minutes, and make sure the pressure does not
decrease.
3 Pressurize to 4.15 MPa and measure the surrounding temperature and refrig-
erant pressure.
(3) I f the specified pressure holds for about one day and does not decrease, the
pipes have passed the test and there are no leaks.
• If the surrounding temperature changes by 1°C, the pressure will change by
about 0.01 MPa. Make the necessary corrections.
(4) If the pressure decreases in steps (2) or (3), there is a gas leak. Look for the
source of the gas leak.
A Nitrogen gas F Outdoor unit
B System analyzer G Stop valve
C Lo-knob H Liquid pipe or high-pressure pipe
D Hi-knob I Gas pipe or low-pressure pipe
E To indoor unit K Service port
Precautions when using the charge valve (Fig. 4-15)
Do not tighten the service port too much when installing it, otherwise, the valve core
could be deformed and become loose, causing a gas leak.
After positioning section B in the desired direction, turn section A only and tighten it.
Do not further tighten sections A and B together after tightening section A.
en
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