Choose a method for the refrigerant, environment and question being asked. Refrigerant-sensitive electronic detectors, ultrasonic instruments and approved bubble solutions detect different effects. A sensitivity figure or a refrigerant-table entry does not establish suitability for every refrigerant or approval for a flammable atmosphere.
Source-based explanation
How do infrared, heated-diode, ultrasonic and bubble methods differ?
Infrared and heated-diode detectors respond to specified refrigerants through their sensor mechanisms; ultrasonic instruments respond to sound, while leak-detection solutions reveal bubbles at accessible leak paths. Each method therefore leaves different questions unresolved. Select against the named refrigerant, conditions and required procedure rather than assuming that one sensitivity figure makes methods interchangeable.
| Method | Detected effect | Main limits to check |
|---|---|---|
| Infrared | Absorption in sensor-specific infrared bands | Named refrigerants, response, contamination and environmental limits; not every gas is detectable |
| Heated diode | Sensor response associated with specified refrigerants, commonly halogen-containing gases | Sensor ageing, contamination and gas coverage; do not assume a response to pure hydrocarbons |
| Ultrasonic | High-frequency sound associated with gas flow | Pressure difference, leak geometry, background noise and access; it does not identify the gas |
| Leak-detection solution | Visible bubble formation at an accessible leak path | Surface access, solution/material compatibility, temperature and suitable conditions |
No method is a blanket substitute for the method required by the equipment procedure or applicable leak-check obligations. A negative indication means no indication under that setup; it is not proof that every possible leak path is absent.
Can grams per year be converted directly to ppm?
A stated minimum leak rate in grams per year is a mass flow under specified test conditions. Parts per million is a concentration at a location. Air movement, distance, sampling and refrigerant properties affect the relationship. There is no universal direct conversion between the two.
Compare a detector’s named test refrigerant and method, response time, warm-up, probe maintenance and verification requirements alongside its sensitivity. A laboratory specification is not our measured performance on a windy or contaminated site.
Does refrigerant detection establish safe-use approval?
R32, hydrocarbon refrigerants and blends have different properties. A general “HFC”, “HFO” or “HC” marketing label is insufficient to establish an exact model’s refrigerant list and safe-use conditions. Obtain the current manual and any required approvals for the refrigerant and environment. A refrigerant leak detector is not automatically a personal flammable-gas safety monitor.
A UV lamp is an illumination source; any fluorescent-dye method also depends on a permitted dye already present in an appropriate system. It does not make the electronic sensor sensitive to additional refrigerants.
What should a leak-detector function-check record include?
Record the detector model, serial number, sensor age, filter condition, warm-up status, sensitivity setting and the manufacturer-specified function-check result. Use an appropriate documented reference leak where required. A response to an improvised gas source is not a traceable calibration or a verified minimum leak rate.
Which guidance applies in Great Britain and Northern Ireland?
Great Britain: check the current GOV.UK qualification and leak-check guidance for the activity and equipment. Northern Ireland: check DAERA’s separate F-gas guidance; do not assume the GB regime applies. Instrument ownership or an App report is not evidence of competence or legal compliance. These explanations do not provide charging, pressure-testing or flammable-refrigerant work instructions.
Which sources support this reference, and what are their limits?
These sources support the terminology, declared capabilities and attributed observations discussed in this reference. Manufacturer declarations and other authors’ observations are not our physical test results. Check the exact model and the source’s stated conditions before applying a claim; the references were consulted on .
- ElitechEU: refrigerant leak detector comparison ↗
Manufacturer specifications; generic refrigerant-family labels do not prove approval for an individual refrigerant.
- AC Service Tech: ultrasonic leak detection ↗
Educator with commercial links; capability explanation, not our comparative test.
- GOV.UK: checking F gas equipment for leaks ↗
Official leak-check guidance; do not infer applicability from a tool specification.
- GOV.UK: qualifications to work with F gas ↗
Current official guidance; follow its territorial scope and activity-specific requirements.
- DAERA: fluorinated greenhouse gases in Northern Ireland ↗
Northern Ireland authority; consult the separate NI regime and linked current guidance.
What should stay with the reading?
A useful measurement record preserves the conditions, instruments, connection details and original reading, then adds any repeated observation or retest. Use the blank field record to keep those details together. See how we assess evidence and our commercial relationship when judging the scope of a published conclusion.
