Refrigerant Leak Detection Should Not Be Complicated

Refrigerant leak detection can be carried out on your own, using three simple methods. You’ll enjoy doing it, if you feel like learning more on air conditioning maintenance.

These methods, in order of cheap to expensive are,

  • soap test,

  • UV light refrigerant leak detection, and,

  • electronic leak detection

Method 1: Soap test:

Soap test is the easiest way of detecting refrigerant leak.

However this test can only be performed on a positive gauge pressure system, i.e. the system has higher pressure than ambient.

Systems, operating under vacuum, may draw in moisture, and cause refrigerant contamination, and parts failure.

We can use this test on current air conditioning systems, using chlorine and fluorine based refrigerant.

The steps are,

  1. switch on the system with cooling, or heating mode,

  2. make a soap solution using dishwasher liquid and water,

  3. pour it into a container.

    Use a mist spray to spray onto hard-to-reach areas,

  4. cover the test area from wind,

  5. clean the area to be tested using a clean, dry cloth,

  6. apply (or spray) the solution onto the test area,

  7. spread the solution along the test area using leather (or non absorbing) cloth,

  8. watch for bubble formation

If there is no bubble formation, then there is no leak at the test area. You may repeat the test on other areas on the system.

Leak presence on the system will cause the soap bubble to expand. Such occurrence will require tube repair, and/or parts replacement.

Wipe dry the area after the test.

Method 2: UV light refrigerant leak detection:

A phenomenon that will normally occur on refrigerant leak is that, lubrication oil leak into the atmosphere.

This happens as the oil is well mixed with the refrigerant. Hence, refrigerant leak will also mean oil leak.

Processed lubrication oil, will have an ultraviolet (UV) component in it. Air conditioning lubrication oil is not left out.

This UV component is easily detectible by UV light, or famously known as Black light.

The working principle of black light

Ultraviolet lights are not visible to human eyes, and hence, we need a UV light, to reflect the UV component on a surface.

UV lights will do exactly that.

UV surfaces that are exposed to UV light will reflect this light, and make it visible to our eyes.

Remember "Gone In 60 Seconds"?

In our case the UV surface is refrigerant and oil leak.

The steps are,

  1. shade the test area,

  2. direct the light onto test area of the air conditioning system, and look for fluorescent mark

UV lights will cost as low as USD 10.00.

This method can detect small amounts of refrigerant leaks.

Method 3: Refrigerant leak detection using electronic device:

Electronic leak detector is most widely used and very accurate refrigerant leak testing method,

It is also known as the halogen leak detector, as refrigerant used in air conditioners are of chlorine and fluorine based material.

These are halogen gases.

How it works?

Leaking refrigerant will be drawn into the unit by a small pump.

The refrigerant will pass through a proportional halogen detector, and it will be translated into electrical signal.

This signal will be amplified and read out will be provided, together with audible sound.

Testing steps are,

  1. switch on the unit,

  2. cover the test area from direct draft,

  3. pass the detection probe near test area and wait for audible and visible signals

Electronic leak detectors cost from as low as USD 50.00.

Alternative refrigerant leak detection method:

Another way of detecting refrigerant leak is by checking oil leak, as refrigerant leak will also expel a small amount of oil.

Wipe a cloth over test area of an air conditioner part, and feel with your finger for presence of oil on the cloth.

Safety in refrigerant leak detection:


  1. do not use bare hands to sense for leak, to avoid frost bite

  2. do leak detection in well ventilated area

  3. evacuate the area, if you smell pungent odour

  4. call for repair as soon as possible, if you have detected pungent smell

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