Mitsubishi Electric PUHY-P1000, Service Handbook

Page: 20 / 334

[1-3 Working with Refrigerant Piping ]
- 11 -
HWE14040 GB
1
Check Before Servicing
1-3-2 Air Tightness Test
No changes have been made in the detection method. Note that a refrigerant leak detector for R22 will not detect an R410A leak.
1. Items to be strictly observed

Pressurize the equipment with nitrogen up to the design pressure (4.15MPa[601psi]), and then judge the equipment's air tight-
ness, taking temperature variations into account.

Refrigerant R410A must be charged in its liquid state (vs. gaseous state).
2. Reasons

Oxygen, if used for an air tightness test, poses a risk of explosion. (Only use nitrogen to check air tightness.)

Refrigerant R410A must be charged in its liquid state. If gaseous refrigerant in the cylinder is drawn out first, the composition
of the remaining refrigerant in the cylinder will change and become unsuitable for use.
3. Notes
Procure a leak detector that is specifically designed to detect an HFC leak. A leak detector for R22 will not detect an
HFC(R410A) leak.
Halide torch R22 leakage detector