LEAK CHECKING & FINDING LEAKS

With today’s high A/C Service demand, A/C technicians are looking for fast, effective methods to check and detect leaks. However, there are industry standards to abide by, and basic steps one must take, in order to perform a successful service. Taking shortcuts can often result in comebacks and issues. So please read more on how to do the job right, the first time, everytime!

Here are the basic methods of leak detection that you should carry out on each system when you service. You will need no special equipment, and this will help to ensure you have happy customers!

PRIMARY EVACUATION & LEAK CHECK

1 - Connect the vacuum pump to the manifold centre port hose and evacuate through the high side only until a vacuum of around 28 in/hg (95 kpa gauge pressure) is reached. The low side should drop below zero within a few minutes. If not, a blockage is indicated.

2 - With the manifold gauge shut off, check the vacuum loss after 15 minutes. If the loss is more than 0.5 in/hg (2kpa) a leak is evident which must be located and repaired. It may be necessary to add some refrigerant to locate this leak. If a leak ls located at the shaft seal of a new compressor, run the system for 10-20 minutes to “bed in” the seal and re-check for leaks. A good practice is to use a digital vacuum gauge which will help to identify very quickly any loss of vacuum and then any leak in the system.

SECONDARY EVACUATION

1 - Evacuate the system to 29.2 in hg or more (99 kpa on the test gauge) and hold this vacuum for at least 45 minutes. Some systems will require a much longer vacuum, depending on age, moisture, contamination, etc. Always take ambient conditions into account; on humid days 60-120 minutes is recommended.

2 - If adequate vacuum cannot be reached it indicates that moisture is still in the system (and is being boiled off) or that the vacuum pump is not performing properly (e.g. dirty oil), or is of insufficient capacity.

PERFORMANCE & FINAL LEAK CHECK

1 - Check the pressures with the engine off (0 rpm), and again at 1500-1750 rpm. Compare the gauge readings with the system pressure guides on page 797. Check the vent temperatures. If they are not correct, take steps to rectify this.

2 - Leak test thoroughly with an efficient electronic leak detector, or, if using fluorescent dye, with an ultraviolet detector. Note: gas (flame) type detectors do not work with R134a.

3 - Remove the charging lines and replace the service valve dust caps.

4 - Do not release the vehicle unless you are completely satisfied that the system is functioning and that there are no leaks or problems.

IMPORTANT: Remember that there are no short cuts to proper, successful servicing.

LEAK DETECTORS

Stay tuned, for more information about the different types of Leak Detectors, their advantages and disadvantages.

There is a new breakthrough in leak detection for those hard to find leaks, with a new tracer gas (mixture of hydrogen and nitrogen) coupled with a special detector that finds the leak everytime!

Feel free to contact the Team at Highgate at sales@highgateair.com.au or call Tech-Support on 1800 15 15 15.