Manual for Refrigeration Servicing Technicians - UNEP - Division of ...

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Servicing Practices
Detection methods
When a system is thought to have a leak, the whole system should be
checked, with leaks found being marked for rectification. One should never
assume a system has only one leak.
Leak detection is the manual procedure, carried out by a qualified
technician, of checking refrigeration systems to identify possible
leaks in tubes, joints and/or connections, etc.
Generally, the main methods for detecting leaks in the servicing field are:
Using soap solution 4
Using an electronic refrigerant detector 4
Using an ultra-violet lamp 4
Using a halide torch 4
Note: Fault-finding
There are a number of problems that may develop in RAC systems
that would have the same symptoms as a refrigerant leak. For
example: the fan, the compressor and various controls could be
in operation, but the system is not cooling. It is sensible to always
determine the other possible reasons for poor operation before
recharging the refrigerant into a system. Also adding refrigerant to
a system that does not necessarily need it can adversely affect its
performance, including reducing its efficiency. It can also present
significant safety hazards such as causing elevated pressures
above what the system can tolerate.
Topping-up
If a system has a deficit of refrigerant, it is highly likely that this is
because of a refrigerant leak. Often, technicians take the approach
of quickly “topping-up” a system to its original charge amount,
since this a quick and easy way of getting the system to work
properly again. However, this is only a temporary, costly, and
environmentally unacceptable approach to take.
No refrigerant should be added to the system without first
locating and repairing the leaks. Simply adding refrigerant will
not permanently correct the problem, and in fact, it accelerates
the degradation of the system in the longer term, thus reducing
its operational lifetime. Instead, the technician should identify the
leaks before recovering the refrigerant, to avoid contaminating
the surrounding air with refrigerant from a newly open system,
remembering that refrigerant should not be vented to the air.
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