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Guide

How to Test a Refrigerant Leak Detector Before Use

A refrigerant leak detector with a worn sensor or a fouled tip looks exactly like a working one until it misses the leak. A short check before each job, against a known reference leak or a whiff of refrigerant, proves it responds. This guide gives the procedure and what a failed check means.

By the Akermin Editorial Team · 3 min read

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Switch the detector on in clean air and let it warm up and zero for the stated time. Inspect the probe tip filter; replace it if oily or discolored. Hold the probe to a reference leak (typically 3 g/yr) for a few seconds: the detector should indicate within about two seconds and recover within a few seconds of removal. If no reference leak is available, a momentary whiff from a refrigerant cylinder or a loosened Schrader cap confirms response, not sensitivity. A weak, slow or absent response means a worn sensor, a blocked filter or contamination; replace the sensor before relying on the detector.

Why test

Heated-diode sensors wear with every hour and every hit; infrared cells foul; tip filters clog with oil. None of these produce an error message. A detector that missed a 3 g/yr leak this morning shows the same clean-air reading as one that would have found it. See sensor lifespan and why gas detectors need bump tests.

Procedure

  1. Clean air. Test outdoors or in a room with no refrigerant, solvent or sanitizer in use.
  2. Warm up. Switch on; wait the full warm-up (heated diode 30 to 90 seconds; infrared shorter).
  3. Zero. Let the auto-zero settle or press zero.
  4. Inspect the tip. Remove the filter; if oily, wet or discolored, replace it. Check the probe for kinks.
  5. Reference leak. Hold the probe tip at the reference leak’s port, in still air, for 3 to 5 seconds. Note the time to indicate.
  6. Recovery. Move the probe away; the indication should drop back within a few seconds.
  7. Sensitivity levels. Repeat on low sensitivity if the detector has settings; it should still respond to the reference leak on the setting you will search with.
  8. Record the check for jobs where records are required.

Without a reference leak

  • Loosen a Schrader cap on a charged system slightly and hold the probe near it; retighten.
  • Crack a refrigerant cylinder valve for an instant near the probe (outdoors; releasing refrigerant is regulated, keep it to a whiff).
  • Hold the probe near a can of compressed duster containing HFC (check the propellant).

These confirm the sensor is alive. They do not confirm it meets 3 g/yr, and a heated-diode sensor past its life can respond to a whiff and miss a small leak. Buy a reference leak if you rely on the detector.

Interpreting

Result Meaning Action
Indicates within 2 s, recovers in seconds Healthy Use
Indicates slowly, weak signal Sensor aging or filter partly blocked Replace filter; if unchanged, replace sensor
No response Dead sensor, blocked probe, or still warming Re-warm; check probe; replace sensor
Constant indication in clean air Contaminated sensor or air; failed zero Move to cleaner air; replace filter; re-zero
Very slow recovery Saturated sensor Leave in clean air; avoid direct cylinder blasts

Keeping it working

  • Cap the probe when not in use; keep the tip out of oil and water.
  • Track sensor hours or age; heated-diode sensors are consumables.
  • Store at room temperature; charge the battery.
  • Do not blast the probe with refrigerant to “test” it; it shortens sensor life.

Sensor technology differences are in infrared vs heated-diode detectors; selection in how to choose a refrigerant leak detector.

Inficon D-TEK 3 Refrigerant Leak Detector

Inficon D-TEK 3 Refrigerant Leak Detector

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Fieldpiece - DR58 Heated Diode Refrigerant Leak Detector - Ultra-Sensitive Leak Sniffer with Large, Backlite LCD Screen - Lightweight HVAC Tool

Fieldpiece - DR58 Heated Diode Refrigerant Leak Detector - Ultra-Sensitive

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Products shown because their documented specifications fit this guide. Price and availability are on Amazon and can change.

Frequently Asked Questions

What is a reference leak?

A small sealed source that emits refrigerant at a known rate, typically 3 g/yr, supplied with professional detectors or sold separately. Holding the probe to it confirms the detector meets its sensitivity claim.

Can I test with a refrigerant cylinder?

Yes, roughly. Crack the valve for an instant near the probe or hold the probe near a loosened Schrader cap. It confirms response but not sensitivity; a reference leak is the proper check.

How often should I test the detector?

Before each job or each day of use, and after any event that may have contaminated the sensor (oil on the tip, a large refrigerant hit).

Affiliate disclosure: Akermin earns a commission from qualifying Amazon purchases made through links on this page. Our editorial picks are based on documented specifications and owner feedback, not commissions.