Anyone in the United Kingdom wanting to fit or replace a gas boiler must follow several measures under the Building Regulations. These cover the type of permissible boiler and other features that must be present in the heating system. The work can only be carried out by registered installers, who can be checked through the national register.
Under Part L1 of the Building Regulations, since April 1, 2005, all installed gas boilers must be condensing boilers. This applies whether they are newly fitted or replacements. There is an exception for houses where fitting a condensing boiler would be unreasonably impractical. The installer is responsible for making this decision. A condensing boiler works by taking the steam produced by burning the hydrogen in the gas fuel, then condensing it and reclaiming it as hot water. This process converts more of the gas into heat, reducing the heat that is lost through the flue, and reducing carbon dioxide emissions.
In addition to the condensing boiler, other aspects of a gas heating system may have to be replaced to meet the Building Regulations. Where a property has a floor space totalling more than 150 square meters, there must be separate controls for each area, for example in bedrooms. These must be in the form of thermostatic radiator valves, which automatically lower the temperature of an active radiator if the room gets warmer, for example through sunshine. The entire system must be "fully pumped," meaning that it does not rely on gravity at any point. Boilers must also have an automatic bypass valve, a device designed to automatically maintain a constant water pressure.
Gas Safety Register
Anyone carrying out maintenance work on gas-based products must be on the Gas Safe Register and carry the relevant identity card. As of 2010, around 120,000 gas engineers were on the register, which is maintained by a private company, Capita Gas Registration. Customers can check the identity card of their installer. They can also check the registration is genuine either online or by calling 0800 408 5500. The check can be on either an individual or a company. The identity card will specify the types of work that the installer is qualified to carry out. Examples include pipes, ovens, gas fires and water heaters.
The Gas Safe Register replaced CORGI as Great Britain's registration body in April 2009 and as Northern Ireland's registration body in 2010.