A Pressure Leak Test or Pressure Decay Leak Test involves pressurizing the coil, component or refrigeration circuit with dry air or nitrogen and monitoring for a pressure drop over a preset time period.

• It is an automatic pass/fail test suitable for finding gross leaks, in the range of tens of ounces of refrigerant per year.
• Pressure decay should be used as a preliminary test prior to Helium or Hydrogen Leak Testing.
• Can replace water bath test but does not provide leak location; a tracer gas leak test such as Helium or Hydrogen/Nitrogen mix is required to locate leaks.

Helium or Hydrogen/Nitrogen Mix is injected under pressure into the unit under test (UUT). An integrated leak detector senses the presence of any gas leaking out of the UUT and measures the corresponding leak rate. This test can be performed either in manual or automatic mode.

In order not to contaminate the working environment with large quantities of tracer gas, this test follows a prior Pressure Leak Test aimed to detecting gross leaks.

Refrigerant Sniffing Leak Test of a sealed refrigeration circuit takes place after refrigerant charging.

• The leak detector is a manually-held probe or automatic multiplexer with gas traps
• It is the final leak test and is usually performed during/after run test.
• The leak detector technology is based on an Infrared Sensor which is very sensitive (in the range of 0.03 ounce or 1 grams per year of refrigerant) and offers fewer false alarms compared to Halogen-based detectors.

Helium Recovery is suitable for high productivity leak testing operations where a large quantity of helium is used. It involves recovering helium from the unit under test (UUT), checking and possibly reinstating its concentration, and compressing it back to the required leak test pressure. The process parameters dictate the number and size of the compressors and recovery tanks in the system.