Boiler Spares, Heating & Plumbing Parts
Identify and source genuine heating and plumbing spares for domestic combi and system boilers. Find exact GC numbers and OEM parts for Worcester Bosch, Baxi, Ideal, and Vaillant.
Where to Find Your Model or Part Number
To guarantee 100% compatibility, check these standard locations for model badges, OEM stampings, and serial numbers:
- Boilers: Gas Council (GC) Number on the data plate behind the drop-down front control flap or on top of boiler casing (7 digits: XX-XXX-XX)
- Circulation Pumps: Specification plate on front pump head casing (e.g. Grundfos UPS 15-50 / 15-60)
- Shower Valves: Laser etched on the decorative wall plate or stamped on the brass cartridge body behind the lever handle
Frequently Replaced Components & Spares
Boiler Diverter Valve Cartridges & Motors
3-way diverter valves, hydroblocks, and synchronous stepper motors
Central Heating Circulation Pumps
Modulating and fixed speed boiler circulation pump heads
NTC Temperature Sensors & Thermistors
Clip-on and wet pocket temperature thermistor sensors
Thermostatic Shower Cartridges
Brass thermostatic and ceramic disc replacement shower mixer cartridges
Common Symptoms & Fault Diagnostics
| Observed Symptom | Likely Root Cause | Recommended Action |
|---|---|---|
| Central heating radiators heat up when hot water tap is turned on | Failed or sticking diverter valve cartridge passing flow through to heating circuit | Replace diverter valve cartridge and inspect actuator motor |
| Boiler locks out on ignition failure or overheating fault code | Faulty NTC thermistor, seized circulation pump, or defective flame rectification electrode | Check pump rotation and thermistor resistance values |
| Shower runs scalding hot or freezing cold without temperature blending | Seized thermostatic bi-metallic coil or wax element inside shower cartridge | Remove cartridge and replace or descale |
Compatibility Verification Checklist
Before ordering replacement components, verify these technical specifications to avoid returns:
How to Photograph Your Part for AI Identification
- 1Photograph the full Gas Council data plate label
- 2For diverter valves, take a photo showing the electrical connector plug and pipe clipping points
Safety & Legal Compliance Notice
Gas work MUST by UK law be undertaken by a registered Gas Safe Engineer. Never break gas seals or work inside the room-sealed combustion chamber without certified competence.