Air-Tightness Test - Mitsubishi Electric City Multi R2 Series Installation Manual

9-6. Air-tightness test

Do not use oxygen, flammable gas, or a refrigerant containing chlorine for air-tightness
testing.
- Doing so may result in an explosion. Chlorine will deteriorate the refrigerant oil.
After refrigerant pipe installation is completed, check the system for leaks by conducting an air-tightness test. If there
is a leak, the composition of the refrigerant will change and the performance will drop.
<Air-tightness test procedures>
① Make sure the service valves are closed.
② Add pressure to the refrigerant pipes through the service ports of the high- and low-pressure pipes.
* Pressurize to the design pressure (4.15 MPa) using nitrogen gas.
③ If the pressure holds for one day and does not decrease, the pipes have passed the test and there are no leaks.
If the pressure decreases, there is a leak. Look for the source of the leak by spraying a bubbling agent (e.g.,
Gupoflex) on the flared or brazed sections.
④ Wipe off the bubbling agent.
Ⓐ
Ⓓ
WT08432X01
Ⓕ
Ⓑ
Ⓑ
Ⓒ
HI
LO
Ⓔ
Ⓐ
Nitrogen gas
Ⓑ
To indoor unit
Ⓖ
Ⓒ
Gauge manifold
Ⓓ
Low pressure knob
Ⓗ
Ⓔ
High pressure knob
Ⓕ
Ⓘ Service valve
Ⓖ
Low-pressure pipe
Ⓙ
Ⓗ
High-pressure pipe
Ⓘ
Outdoor unit
Ⓙ
Service port
GB-31