Working with F-gas
The UK has strict laws on who can install and work with F-gas and systems containing F-gas. There are also laws around the sale of F-gas.
Checkmark fully supports, and works in accordance with the UK F-gas regulations and guidance 
.
From UK Government guidance on working with F-gas
It is against the law to work with F gas if you do not have the correct qualifications. You could receive a civil penalty for breaking the law. See the Environment Agency enforcement sanctions policy.
If you see someone working with F gas that doesn’t have the right qualifications, report it to f-gassupport@environment-agency.gov.uk.
What does the Government guidance say?
The following guidance is straightforward. Note that each operation (install, service and maintain, check for leaks etc.) is defined in a separate government document and does not stop you doing the preparatory work of an install. See below.
From UK Government guidance - qualifications to work with F gas
Stationary refrigeration, air conditioning and heat pump (RACHP) systems qualifications.
For RACHP systems you must have qualifications to:
- install new systems (see below)
- service and maintain systems
- check for leaks
- recover gases
- decommission and dispose of old systems
- work on refrigerated trucks over 3.5 tonnes
- work on refrigerated trailers made to be towed by trucks or trailers
You need a:
- category 1 certificate to carry out all activities
- category 2 certificate to install, maintain, service and recover refrigerant from systems containing less than 3kg of F gas, or less than 6kg of F gas if hermetically sealed
- category 3 certificate to recover refrigerant from systems that contain less than 3kg of F gas, or less than 6kg of F gas if hermetically sealed
- category 4 certificate to check equipment for leaks if you do not break into the refrigeration circuit
How is installation defined?
From Regulation (EU) No 517/2014
Article 2 definitions:
(20) ‘installation’ means joining two or more pieces of equipment or circuits containing or designed to contain fluorinated greenhouse gases, with a view to assembling a system in the location where it will be operated, that entails joining together gas carrying conductors of a system to complete a circuit irrespective of the need to charge the system after assembly;
The definition of ‘installation’ is specific and sensible. It prohibits the joining of the F-gas pipes unless you have the qualifications mentioned above. It does not prevent the preparatory work being done by someone without qualification, as long as they don’t touch the F-gas connections. As a DIYer, you are allowed to do what the unqualified team members of an installation company are allowed to do.
The details
It is worth noting these laws, guidance and regulations originate from (EU) No 517/2014 of the European Parliament and of the Council and were brought into UK law following Brexit.