Heatcraft Refrigeration Products FLEXPACK 25006801 User Manual

11

Leak Detection And Evacuation

Leak Testing

After all lines are connected, the entire system must be leak tested. The complete system should be pressurized to 

not more than 150 PSIG with refrigerant and dry nitrogen. The use of an electronic type of leak detector is highly 

recommended because of its greater sensitivity to small leaks. As a further check, it is recommended that this 

pressure be held for a minimum of 12 hours and then rechecked. For a satisfactory installation, the system must be 

leak tight.
Leak detection can be carried out in the conventional manner. If HCFC or CFC tracer gas is used, care must be taken 

to completely remove all traces of the gas prior to introducing HFC’s. Electronic leak detectors are now available that 

will sense HFC’s. This is considered preferable since it removes the possibility of chlorine remaining in the system 

after leak testing with HCFC’s and/or HCFC’s. There is a view that even small quantities of chlorine may act as a 

catalyst encouraging copper plating and/or corrosion and should therefore be avoided.
Within the last several years, manufacturers have developed fluorescent dye leak detection systems for use with 

refrigerants.  These dyes mix with the lubricant and, when exposed to an ultraviolet light, fluoresce to indicate the 

location of leaks. Copeland has tested and approved the Rigid “System Safe” dye and found it to be compatible with 

the compressor materials in systems.

Evacuation

 

 

 

 

       CAUTION: 

Do not use the refrigeration compressor

 

 

 

 

 

 

to evacuate the system. Do not start the

 

 

 

 

 

 

compressor while it is in a vacuum.

Due to the smaller molecule size of HFC’s, they will tend to leak more readily than CFC. Consequently, it is of 

the utmost importance that proper system evacuation and leak detection procedures be employed. Copeland 

recommends a minimum evacuation to 500 microns. In addition, a vacuum decay test is strongly recommended to 

assure there is not a large pressure differential between the system and vacuum pump. Good evacuation processes 

include frequent vacuum pump oil changes and large diameter, short hose connections to both high and low sides 

of the system preferably using bronze braided hose.
A good, deep vacuum pump should be connected to both the low and high side evacuation valves with copper tube 

or high vacuum hoses (1/4” ID minimum). If the compressor has service valves, they should remain closed. A deep 

vacuum gauge capable of registering pressure in microns should be attached to the system for pressure readings.
A shut-off valve between the gauge connection and vacuum pump should be provided to allow the system pressure 

to be checked after evacuation. Do not turn off vacuum pump when connected to an evacuated system before 

closing shut-off valve.
The vacuum pump should be operated until a pressure of 1,500 microns absolute pressure is reached – at which time 

the vacuum should be broken with the refrigerant to be used in the system through a drier until the system pressure 

rises above “0” psig.
 

 

 

NOTE:  Refrigerant used during evacuation can not be vented.

 

 

 

 

Reclaim all used refrigerant. EPA regulations are constantly

 

 

 

 

being updated. Ensure your procedures follow correct regulations.

Repeat this operation a second time.
Open the compressor’s service valves and evacuate the entire system to 500 microns absolute pressure. 
Raise the pressure to 2 psig with the refrigerant and remove the vacuum pump.