Before an engineer can repair a refrigerant leak in the system it has to be located and for this reason leak detection is the first step. If the system has not lost all its refrigerant charge, leak detection may proceed as described in Chapter 3 provided that there is an adequate test pressure within the system. When the entire refrigerant charge has been lost, the system has to be pres- surized. If the leak is found to be minor and on the low side of the system, ‘pumping down’ will be necessary before any attempt is made to repair the leak. Leakage from the high side of the.
