Heatcraft Refrigeration Products H-IM-FL1A, Installating And Operation Manual

11

Line Insulation 

After the final leak test, refrigerant lines exposed to high 

ambient conditions should be insulated to reduce heat pickup 

and prevent the formation of flash gas in the liquid lines. 

Suction lines should be insulated with 3/4" wall Armstrong 

“Armaflex” or equal. Liquid lines should be insulated with 1/2 

inch wall insulation or better. The insulation located in outdoor 

environments should be protected from UV exposure to prevent 

deterioration of insulating value.

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 (or 

dry CO

2

). The use of an electronic type 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. 

Evacuation and Leak Detection 

Due to the smaller molecule size of HFCʼs, they will tend to 

leak more readily than CFCʼs. 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. 

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 

HFCʼs. 

Electronic leak detectors are now available that will sense 

HFCʼs. This is considered preferable since it removes the 

possibility of chlorine remaining in the system after leak testing 

with HCFCʼs and/or CFCʼs. 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.

WARNING: HFC-134a has been shown to be combus- 

tible at pressure as low as 5.5 psig (at  

350˚F) when mixed with air at concen 

trations more than  60% air by volume. At  

lower temperature,  higher pressures are  

required to support combustion. Therefore, 

air should never be mixed with HFC-134a 

for leak detection.

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,” indicates 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. 

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 cannot 

be vented. Reclaim all used refrigerant.

EPA regulations are constantly being 

updated to ensure your procedure follows 

correct regulations.

Repeat this operation a second time.  

Open the compressor 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.