Boiler spares are picked by appliance match first, then by the fault you’re chasing. If you need boiler parts for a straight swap, stick to the exact component and layout the boiler calls for. For boiler service parts or boiler repair parts, a kit or seal set can be the cleaner buy than piecing together individual boiler components. The usual snag is assuming one valve, sensor or seal will fit across similar models.
Glow-Worm Filling Loop
Glow-Worm filling loop spare part (0020026414).
Alpha CD13R Seal Kit Circuit Seals
Seal kit for Alpha CD and CDX boilers with seals, gaskets, washers and O-rings.
Baxi Flame Sensing Electrode
Baxi flame sensing electrode for multiple Baxi boiler ranges.
Vaillant Gas Section with Regulator
Vaillant gas section with regulator, compatible with ecoTEC plus boilers
Viessmann Valves/Fittings Pack System Surface Mounting
Valves and fittings pack for surface mounting Viessmann Vitodens 200-W gas syste…
Biasi DHW Heat Exchanger
Biasi DHW heat exchanger for domestic hot water transfer
Parts Safety Relief Valve - Vaillant / Glow-Worm
Vaillant / Glow-Worm pressure relief valve for boilers
Vaillant Fan with Combustion Cha
Vaillant fan with combustion chamber cover
Baxi Pressure Gauge
Baxi pressure gauge for monitoring boiler system pressure
Worcester Bosch Motor Diverter Valve
Motorised valve to direct hot water between heating and taps in combi boilers
Start with the appliance match and the fault, then check the system and flue before you look at anything else. That’s where most wrong orders happen with boiler spares, not on the part itself. Condensing is the baseline on most modern jobs, so the real split is usually system, combi or regular, plus whether you’re dealing with gas or oil. Filtration matters where the system has been carrying debris. Gas Safe fitting responsibility can change what you’re allowed to supply. In practice, boiler parts that look close enough often aren’t once the model and layout are checked.
Some boiler spares are bought as individual boiler parts when you know exactly what’s failed. That keeps the job tight and avoids paying for bits you won’t use.
Boiler service parts suit routine maintenance. They’re usually the wear items you expect to change more than once.
Boiler repair parts are the better call when you’re chasing a specific fault and need the exact component back in. Boiler replacement parts make sense where the original has gone beyond a sensible repair, but you lose the speed of a simple swap if the appliance is awkward to strip.
On the Central Heating side, the usual mistake is buying by description alone instead of by the actual layout of the boiler components.
Exact-match boiler parts are the right call when you know the appliance and the fault. You avoid fit issues and function mismatches. The trade-off is usually price and lead time.
Universal or mixed boiler components can suit older repairs, but they can cost you time when the original setup is awkward. For parts around the job rather than inside it, Central Heating Accessories is the next stop. If the fault sits in the zone control rather than the boiler itself, Motorised Valves is where you’d go next.
Once you’ve got the main unit sorted, the next call is what else needs to sit around it on the job. With boiler spares, that usually means the parts that finish the repair properly - controls, filters, and the right boiler accessories - rather than the failed part on its own.
A lot of call-backs come from missing the small item that should’ve been changed at the same time. The other common issue is fitting a part that’s right in principle but wrong for the appliance family. If you’re also ordering from central heating accessories or motorised valves, keep the system layout in mind and don’t mix in parts that belong to a different setup.











