Air Tightness Test (Refrigerant Circuit) - Mitsubishi Electric CMB-WM108V-AA Service Handbook

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[7] Air Tightness Test (Refrigerant Circuit)

No changes have been made in the detection method. Note that a refrigerant leak detector for R22 will not detect R410A and R32
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 the 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 the 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, R32) leak.
HWE1708A
Halide torch R22 leakage detector
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