Building Regulations for boiler installation

What's changing?

A revised version of Approved Document L (Part L) of the Building Regulations has been published which will take effect from 15 June 2022. With this revision there are a number of changes to guidance and requirements for boiler regulations covering both the new build and retrofit markets.

With regards to existing dwellings the main points are:

Complete New System Installations require:

• An appropriate heat loss calculation for the dwelling
• A system sizing methodology that takes account of the properties of the dwelling, such as the Chartered Institute of Plumbing and Heating Engineering’s Plumbing Engineering Services Design Guide
• The system should be designed to operate at a 55°C heating flow temperature

Boiler Swaps require:

• Where a combination boiler is used, the boiler type should be selected to modulate down to the typical heating load of the dwelling

Document BS 7593:2019 – Code of practice for the preparation, commissioning and maintenance of domestic central heating and cooling water systems – has been incorporated into Part L guidance, so what was best practice advice will become a requirement.

What does this mean for installers?

As well as cleansing and flushing the system when installing a new boiler to remove debris and sludge and then treating the water with inhibitors, an in-line filter must be installed in the circuit to capture particles and prevent them from entering the boiler.

Sludge and debris in the system is a major cause of boiler breakdowns. By installing a filter to prevent the build-up of sludge, heating systems will be more energy efficient and reliable, leading to lower fuel bills, reduced breakdowns and lower carbon emissions.

For more information you can find the Approved Document L here. Please note this applies to England only.