Mitsubishi Electric CITY MULTI PURY-P-YNW-A Manual De Instalación página 33

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9-6. Air-tightness test

Do not use oxygen, flammable gas, or a refrigerant containing chlorine for air-tightness

- 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.

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