Twin Eagles AM-50BAE-AD - Manual (Page 40)

40
U1VA6060209
6) Replacement Copper Tubing [R134a]
The copper tubes currently in use are suitable for R134a. But do not use them if oily inside.
The residual oil in copper tubes should be as little as possible. (Low residual oil type copper
tubes are used in the shipped units.)
7) Evacuation, Vacuum Pump and Refrigerant Charge [R134a]
Never allow the oil in the vacuum pump to flow backward. The vacuum level and vacuum
pump may be the same as those for current refrigerants. However, the rubber hose and gauge
manifold to be used for evacuation and refrigerant charge should be exclusively for R134a.
8) Refrigerant Leak Check
Refrigerant leaks can be detected by charging the unit with a little refrigerant, raising the
pressure with nitrogen and using an electronic detector. Do not use air or oxygen instead of
nitrogen for this purpose, or rise in pressure as well as in temperature may cause R134a to
suddenly react with oxygen and explode. Be sure to use nitrogen to prevent explosion.
[b] Refrigerant Recovery
The refrigerant must be recovered if required by an applicable law. No refrigerant access
valve is provided in the unit. Install a proper access valve on the low-side line (ex. compressor
process pipe). Recover the refrigerant from the access valve, and store it in a proper container.
Do not discharge the refrigerant into the atmosphere.
When replacing the drier, take the opportunity to also fit a high-side access valve for ease of
charging liquid refrigerant.