There’s no maximum period of time between leak checks on:

• hermetically sealed refrigeration and air conditioning systems unless they contain F gas equivalent to 10 tonnes of carbon dioxide (that’s equal to 2.6kg of HFC404A or 7kg of HFC 134a)
• refrigeration systems in vehicles, except refrigerated trucks or trailers

If you install a system to automatically detect leaks, you can double the period of time allowed between leak checks. For example, with a leak detection system you must check a product that contains F gas equivalent to 5 tonnes of carbon dioxide every 2 years.

When to fit automatic leak detection

You must fit a leak detection system if your equipment contains F gas equivalent to 500 tonnes or more of carbon dioxide. This does not apply to electrical switchgear or organic Rankine cycles installed before 1 January 2017.

The leak detection system must alert you, or a service company responsible for your equipment, if it detects a leak.

You must have your leak detection system checked:

• every 6 years on electrical switchgear
• every year on all other equipment containing F gas

Updated 22/08/25 source: https://www.gov.uk/guidance/checking-f-gas-equipment-for-leaks