Airtight Test And Evacuation - Mitsubishi Electric CITY MULTI PUMY-71 Manuel D'installation

I When using the multi-distribution piping on outdoor unit method.
Use the following procedure to connect the refrigerant piping.
1 Remove the knock-out from the right side piping cover.
2 Use the 7 screws included with the multi-distribution piping on the outdoor unit kit to the right-side surface of the outdoor unit.
3 First connect the liquid line piping and then the gas line piping between the outdoor unit and multi-distribution piping on outdoor unit kit.
• There is an extra connection pipe for the gas line included in the package for compatibility with all units. Dispose of it after installation.
4 Connect the multi-distribution piping on outdoor unit kit with the indoor unit. Note that there are different pre-determined union sizes.
• If the diameters on the multi-distribution piping on outdoor unit kit do not match, or if there are not enough, use a difference diameter joint.
5 If there are fewer units being installed than there are connections on the multi-distribution piping on outdoor unit kit, do not loosen the flare nuts on
those remaining and leave them as they are. (They are sealed by the copper caps.)
6 Use an open-end wrench to tighten all flare nuts to the proper tightness.
7 After the sealing test has been performed, insulate the piping connections on the multi-distribution piping on outdoor unit kit by wrapping pipe cover
provided and secure with the band.

7.5. Airtight test and evacuation

1 Airtight test
Airtight test should be made by pressurizing nitrogen gas to 3MPa(30kg/cm
stop valve closed. Be also sure to pressurize both liquid or high-pressure pipe and gas or low pressure pipe.)
The test result can be judged good if the pressure has not been reduced after leaving for about one day after completion of nitrogen gas pressurization.
2 Evacuation
Evacuation should be made from the service port provided on the outdoor unit's stop valve to the vacuum pump commonly used for both liquid or high-
pressure pipe and gas or low-pressure pipe. (Make evacuation from both liquid or high-pressure pipe and gas or low-pressure pipe with the stop valve
closed.)
Remember: Never carry out air purge by refrigerant.
To indoor unit
System analyzer
LO HI
Lo-Knob Hi-Knob
Freon 22
* A high-precision gravimeter measurable up to 0.1kg should be used.
If you are unable to prepare such a high-precision gravimeter, you may use a charging cylinder.
Multi-distribution
piping on outdoor
unit kit
Screw
Piping cover
Remove
Nitrogen
gas
Outdoor unit
Stop valve
Liquid pipe or high-pressure pipe
Gas pipe or low-pressure pipe
Service port
3-way joint
Valve
Vacuum pump
Valve
cylinder
Scale
Piping cover
Liquid line Gas line
2 G). For the test method, refer to the following figure. (Make a test with the
To indoor unit Outdoor unit
Stop valve
For PUMY, to indoor unit
System analyzer
HI
LO
Lo-Knob Hi-Knob
Note:
Be sure to replenish appropriate amount of refrigerant.
(Refer to pages 8 to 11)
Refrigerant may cause trouble if there is too much or too
little.
Warning:
When installing or moving a unit to another place, do not
mix anything other than specified refrigerant (R-22) into
the refrigeration cycle. If air is mixed, the refrigeration cy-
cle may obtain abnormally high pressure, resulting in a
burst pipe.
Gas/Liquid
ø12.7
ø6.35
ø12.7
ø6.35
ø12.7
ø6.35
ø15.88
A
ø9.52
ø15.88
ø9.52
As viewed from A
Secure with band
Liquid pipe or high-pressure pipe
Gas pipe or low-pressure pipe
Service port
13