A to Z of Refrigerant leak detectors

Leaks increase the cost of running air conditioner systems as it reduces the cooling efficiency and in turn increases the electricity consumption. Another adverse effect is on ozone layer. All systems leak refrigerant. One pound in two years is acceptable but if it leaks more than that, we need to repair the leak.


Refrigerants are covered under European fluorinated gas regulations (F GAS REGULATIONS).Check below points

• You have to repair the leaks before charging the system.

• You need to leak test once every years if charge is less than 30 kg and twice a year if charge is more than 30 kg. A permanent Fixed leak detection for systems over 300 kg is needed. Fix and retest within one month.

• You need to be certified in order to handle leaks.

How to check for refrigerant leaks

• Do a visual inspection and look for oily spots because compressor oil will flow from the leaking place.

• Look for corrosion and rusting coils.

• Check refrigerant lines near the compressor.

• Check all flare connections. They can become loose because of vibrations.

• Refrigerant line must not touch other lines.

• check evaporator coil

• check all flare connections. They can become loose because of vibrations.

•Check vent lines, O rings and all the valves.

The major cause of leakage is vibration caused by temperature and pressure changes. These changes are highest at discharge line of compressor and gas line on heat pump

Types of refrigerant leak detectors

Ultraviolet leak detector

It is also known as black light leak detector. Phosphorus dye is installed inside the air conditioner during the manufacturing. If a leak is there, phosphorous will come out with refrigerant. Ultraviolet leak detector is used to spray black light over leaking area and if the leak is present, it will glow with a bright yellow color. It is perfect for quick testing of leaking systems.

Halide leak detectors

It is Flame based leak detector buy its use is stopped now because of Fire hazard and poisonous gases. The halide Device sits on top of propane tank and is burned in the presence of copper. The flame will change color once it comes in contact with leaked refrigerant(Green or purple).

Ultrasound Leak detectors

It senses the sound coming from leak. It is better for systems with lots of surrounding air.

Refrigerant must be charged as per the specifications. Undercharge systems suffers from performance loss while Overcharging will increase the chances of leakage.

Electronic leak detector

It is the most sensitive of all leak detectors. It’s a handheld device with an attached probe. Just move the probe along all the lines slowly (not more than 10 inches per 5 seconds). if it senses a leak ,you will hear an audible alarm or a flashing visual light. Make sure that probe never makes direct contact with refrigerant lines.

Types of electronic leak detectors

A: Heated diode detector

It needs charging after every 96 hours or 4 days of use.

B: Infrared (IR) detector

It needs less charging as compared to Heated diode detector. Avoid direct contact with oil or lubricants.

All electronic leak detectors must be checked every year (once) and it should detect a flow of 5g/year under F Gas Regulations.

The flow rate is 5g/year, Once you open the valve of refrigerant cylinder. Electronic leak detector should catch it. If it can’t then it is not working properly.

Advantages of electronic leak detectors

The biggest advantage is the sensitivity settings. Because of this, you can use the same electronic leak detector to check for leakage of different refrigerants like R410A, R22, R134A, etc.

It has settings for CFC, HCFC(R22) and HFC(R134A) refrigerants. CFC refrigerants has chlorine and it can be detected at low sensitivity. HFC contains fluorine instead of chlorine. So you have to increase sensitivity as it difficult to detect fluorine instead of chlorine.

Leak detection spray or soapy water

It is better solution for large leaks as Sensitive electronic detector will activate in any place of surrounding leakage area. You just need to apply it on the leakage area and bubbles will form where refrigerant is leaking. It must be used only when no other form of leak testing is available.

Maintain leak records

Under F gas regulations, any system with more than 3 kg of HFC must maintain a record of total refrigerant charge, addition and removal of refrigerants, leak tests and the actions taken to repair the leaks. It is better to maintain record of refrigerant leaks as it will be of great help to any technician coming for leak tests.