Baxi Boiler Parts: How to Find the Right One for Your Boiler

Most Baxi faults come down to a short list of parts, and most of those parts are cheap. The hard bit is not the price. It is getting the right one, because Baxi has made a lot of boilers that look alike, and a part for a 600 combi will not necessarily fit a Duo-tec 2 even if the description reads the same. 

So this guide starts with your boiler, not the part. Find the model, then the symptom, then the part number. We list over 100 Baxi boiler spares, and every one of them needs a Gas Safe registered engineer to fit. 

Who Can Do What? 

Your Baxi is a gas appliance. In the UK, any work on the gas or combustion side, and in practice anything behind the front casing, is Gas Safe registered work. We sell the parts. We do not fit them, and every Baxi spare we list says so on the product page. 

What you can do yourself, following the user section of your manual: 

• Read the pressure gauge
• Top the pressure up with the filling loop if it has dropped
• Press reset once after a lockout
• Check the condensate pipe outside for freezing in cold weather 
• Bleed radiators

What you should not do: open the case, remove a component, or press reset repeatedly. A reset clears a clockout. it does not fix whatever caused it. If a Baxi 600 or 800 locks out again straight after a reset, which is one of the most searched Baxi problems there is, the boiler is telling you a part has failed. Pressing the buttong again will not change that. 

Find Out Exactly Which Baxi You Have

Look for the data badge. It is usually inside the front cover or on the underside of the boiler, and your manual will show where. Note down: 

• The model and output - for example, "800 Combi 2 30" or "Duo-tec 2 Combi 28 GA". The output in kW matters for expansion vessels and some hydralic parts. 
• The GC Number - This is the gas appliance number and it identifies the exact model
• The serial number - some Baxi parts only fit a range of serial numbers. Out 7690350 PCB Kit, for example, fits the Platinum and Duo-tec 28 HE A only from specific serial numbers. 

The Part Number on the Old Part Might Not Be the One You Order

Baxi supersedes part numbers constantly. The number printed on the failed component if often the old one, and the part that replaces it is listed under a new number. This catches people out more than anything else. Here are the supersessions on our own listings: 

If your number is not in that table and not on our site, email it to us anyway. It may simply have been superseded by something we do have in stock. 

Which Part is Behind Which Symptom

Two things worth knowing about pressure. First, the safety valve on a Baxi combi or system boiler opens at 3 bar, and it discharges through a pipe that usually runs outside. If that pipe drips, the valve is either doing its job because the pressure is too high, which points at the expansion vessel, or it is worn and letting by. Replacing the valve without checking the vessel often means replacing it again. Second, most Baxi manuals give a cold pressure of around 1 to 1.5 bar. Check the figure for your model, and top up with the boiler cold. 

Parts by Model Family 

This is where most wrong orders come from. The tables below group our Baxi spares by the boiler range each listing names. If your boiler is in a family but the part you need is not shown, call us. We list more than we can fit in this article. 

Baxi 600 and 800 series 

People often ask what the difference is between the 600 and 800. For parts, the useful answer is that many of the core components are shared. Our listings name both ranges for the PCB, the ignition electrode and its gaskets, the hot water heat exchanger, the condensate pipe kit and the diverter valve kit. 

Duo-tec 2, Neta-tec Combi GA and related

The newer GA platform has its own electrodes, lead, gas valve and board on our listings, separate from the first-generation Duo-tec parts below. Do not assume a Duo-tec part fits a Duo-tec 2.

Duo-tec, Platinum and Megaflo system boilers

The first-generation Duo-tec, the Platinum and the Megaflo-branded system boilers share a long list of parts on our listings.

Older Baxi, Main and Potterton boilers

If you have an older Combi, Solo, Main, Gold or Promax boiler, the parts are often different again, and the electrodes are the classic example.

Expansion vessels: size matters, and so does the model

Expansion vessels are one of the most searched Baxi parts, usually as "8 litre" or "10 litre". Our listings size them two ways: by output for the general vessels, and by model for the specific ones.

Genuine or compatible?

About half our Baxi listings are genuine Baxi parts. Baxi gives a one-year warranty on its genuine spares. The rest are listed as compatible parts made to match the original specification.

Which to choose is mostly about the boiler's age and warranty. If your Baxi is still inside its manufacturer warranty, speak to Baxi before anyone fits anything, because the manufacturer may want to attend itself. For an older boiler a compatible part is often a perfectly sensible repair. Where both exist, the product page tells you which you are looking at, and the spares desk will tell you if a genuine version is available.

Repair or replace? The parts are rarely the expensive bit

We counted every Baxi boiler spare we list by its ex VAT price band.