York R-410A, Technical & Service Manual, Page: 263 / 385

Installation
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3. Observe the pressure
Add and keep pressure 28.0kgf/cm2G for more than 24 hours, pass if there’s no pressure
drop. If the pressure falls, it should be corrected. After that, if the pressure is still lower than that
when adding pressure, the leakage should be checked out and corrected.
Correcting method
If there’s 1
℃
difference in temperature, there will be 0.1kgf/cm2 difference in pressure.
Correcting formula: actual value = pressure in the stage of adding pr(temperature in
the stage of adding pressure – observed temperature) x 0.1 kgf/cm2
Compare the correcting value and adding pressure value to see whether the pressure falls.
Look up the leakage point in three phases when the pressure falls.
Check the leakage by ears---can hear loud noise of the leakage.
Check the leakage by hands---put the hands in the pipe connection to check the leakage.
Check the leakage by suds---the leakage point will emit air bubble.
Check the leakage by halogen detector.
Use halogen detector when finding the tiny leakage point or pressure falls but no leakage
point can be found during the adding pressure test.
Place the nitrogen under 3.0 kgf/cm2.
Add fluorine to the point 5.0 kgf/cm2 (mixed state of fluorine and nitrogen).
Check by halogen detector, alkyl detector, electric detector and so on.
If no leakage can be found, continue to add pressure to 28.0 kgf/cm2 , then check again.
4. Precautions
- The maximum pressure in gas proof test should not exceed 28.0 kgf/cm2.
- If the pipe is too long, check by sections.
- Indoor side
- Indoor side + Vertical pipe
- Indoor side+ Vertical pipe +Outdoor side