Loss of refrigerant can have a direct impact on global warming will eventually cause inefficient and unreliable operation. The EU F-gas Regulation No. 842/2006 came into force in 2007. Operators of HFC equipment must prevent leakage, ensure leak checks are carried out and repair any leaks as soon as possible as well as arranging proper refrigerant recovery. The detailed requirements concerning frequency of mandatory checks, qualifications for personnel and other matters can be obtained from the Institute of Refrigeration (IOR). Certain equipment will need instruction manuals containing information about the HFC in use. Clarification of some points is ongoing and installers should keep up to date via the IOR website.
A study of types of leaks and methods of minimizing them has been made by Bostock (2007). To determine if leaks exist, new equipment may be left pressurized at leak test pressure overnight or for longer periods, and any pressure drop noted. Pressure will change with temperature, and so this must be taken into consideration. Another option is to leave the equipment under vacuum for a period. A traditional way of finding leaks is to use soapy water. Many people discount it, but for finding leaks it is possibly the most effective method and can successfully find very small leaks. All leaks must be fixed before equipment is put into service.
Electronic leak detectors are now widely used. Details of various types and their suitability for different refrigerants can be found in the IOR Service Engineers’ bulletins. It is important to use a detector of sufficient sensitivity; it should be capable of detecting a leak of 5 g/year. Fluorescent additives can be added to the system, and when they are carried round by the oil, a leak can be pinpointed with an ultraviolet lamp. The plant must be cleaned after use and any additions of dye to the system must be noted because unlimited use could impair oil properties.
Posted in Refrigeration and Air Conditioning