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13 WORKING ON THE SEALED SYSTEM
13.1 Safe Work Practices
Safe work practices cannot be overstated. If your work practices are not to a safe standard, you may cause
damage not only to your customer’s property, but also to yourself.
It is important that on all refrigeration systems being serviced, the type of refrigerant is identified before work
commences. The serial plate will indicate the gas type and so will the label on the compressor.
Do NOT charge flammable refrigerants into refrigerators designed to operate on R12 or R134a.
If the system contains R600a refrigerant:
• Don’t work on the appliance in a confined space. Always work in a well-ventilated area.
• Don’t use mechanical devices to speed up the defrosting process.
• Don’t use electrical tools (e.g. battery drill) that could be a source of ignition inside the appliance in case
the appliance should have a gas leak.
• Always purge the system with Dry Nitrogen prior to lighting a gas torch.
13.2 Leak Detection
There are special leak detectors available for R600a. Don’t use your old leak detector that you have for R12
/ R134a with the R600a system unless it specifies that it can be used for R600a.
Leak detection fluid and a small paintbrush works well.
13.3 R600a Operating Pressures
The working pressures are a lot lower than what we have seen with R12 and R134a systems.
• The high side 600Kpa / 90PSI @ 32
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350Kpa / 50PSI @ 18
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• The low side -50Kpa / -14.8 inches vacuum @ 32
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-30Kpa / -9 inches vacuum @ 18
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13.4 Reclaiming
If venting R600a out of a system that is being worked on, there is no legal requirement to reclaim it. Note,
however, that the refrigerant is flammable.
• Be aware of the surroundings.
• Have no ignition sources nearby.
• Either release it outside or use a hose to vent it outside.
• R600a is heavier than air and will hang around at floor level.
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