Baxi 5137531 Fan Pressure Switch, Air Pressure Switch, Boiler APS, Fan Proving Switch, Differential Pressure Switch

Boiler spares are replacement parts for gas, LPG and oil boilers: printed circuit boards, fans, gas valves, pumps, diverter valves, heat exchangers, sensors, pressure gauges, burners, electrodes, seals, casing panels and flue parts. Most are made for one manufacturer, and often for a narrow range of models, so identifying the boiler correctly matters more than anything else.

Identify the boiler first

Find the data badge, usually behind the front panel or under the controls cover. It shows the manufacturer, the model and the GC (Gas Council) number, a seven-digit reference for the exact appliance. Natural gas and LPG versions of the same boiler usually have different GC numbers, and parts can change between production runs, so the GC number and serial number are the safest way to match a part. The boiler's installation and servicing manual lists the parts for each model.

Part numbers and replacements

Search by the manufacturer's part number where you have it. Manufacturers sometimes replace a part with a newer version under a new number; only use a replacement that the manufacturer lists for your model. Some repairs need a kit rather than a single part, for example a part supplied with new seals or fixings.

Safety

By law, work on gas boilers and their gas parts must be carried out by a Gas Safe registered engineer qualified for that type of appliance; ask to see their ID card before work starts. Oil boilers should be worked on by a suitably qualified technician.

For thermostats and programmers, see heating controls.