# Record an F-Gas leak check

Source: https://help.mucka.ai/gas-certs/record-an-fgas-leak-check
Category: Certificates
Last updated: 2026-08-18

> The statutory refrigerant leak check record. Mucka works out the CO2 equivalent and the legal check interval from the charge, then books the next one into your service reminders.

The F-Gas Leak Check Record is the one air conditioning document required by law. Systems holding F-gas refrigerants above a certain charge must be leak checked on a fixed schedule, the record must be kept for five years, and the Environment Agency can ask to see it. There is no prescribed form for it, so this is a compliant record rather than a copy of anyone's pad — and Mucka does the arithmetic the regulation turns on.

## The clever part: the interval is worked out for you

The legal check interval depends on the system's charge expressed as **CO2 equivalent**: the refrigerant charge in kilograms times the gas's global warming potential. Under 5 tonnes needs no scheduled check; 5 to 50 is every 12 months; 50 to 500 every 6; over 500 every 3, and automatic leak detection becomes mandatory. Fitted leak detection doubles each interval.

Pick the refrigerant, put the total charge in, and Mucka shows the CO2 equivalent and the interval on the form. The **next check date** is suggested from it, and when you approve, the next check lands in your [service reminders](/help/schedule/service-reminders) at the right cadence — every 3, 6 or 12 months as the law actually requires, not a flat year.

## Before you start

Turn **Air Con** on in the certificate settings (see [Set up your certificates](/help/gas-certs/set-up-gas-and-oil-certificates)) and add your **company F-Gas certification number** and each engineer's **F-Gas certificate number**. On F-gas refrigerants these are required by law, so the certificate will not approve without them. The **ACRIB SKILLcard number** is optional and prints when you have it.

## Fill it in

1. Start it from the job's certificates card, or from [**Certificates**](/gas-certs) with **New certificate**, the **Air Con** tab, then **F-Gas Leak Check Record**.
2. If Mucka already knows the system (a commissioning certificate created it, or you have checked it before), it offers to carry the system and refrigerant details over so you never re-key a serial number.
3. Say what kind of check it was: a scheduled check, a follow-up after a repair, or a leak detection function check.
4. Record the method, **direct or indirect**, plus what you actually used and the instrument. Mucka nudges you if the instrument's calibration is over a year old.
5. Record the result. A found leak asks where it was, what you did about it, and suggests a follow-up verification check a month out.
6. Any refrigerant added or recovered goes on the record, with whether it was virgin, recycled or reclaimed and the cylinder it came from.
7. Sign and approve. The PDF goes to the customer like any other certificate, and the next check is in your reminders.

Systems on propane, CO2 or the new HFO refrigerants have no statutory F-Gas schedule — Mucka says so on the form rather than inventing a date.