Potterton is one of the UK’s oldest heating brands, established in the early twentieth century. Acquired by the Baxi Group, Potterton’s current boiler range — principally the Promax and Titanium series — shares significant engineering commonality with Baxi’s own models. This cross-compatibility is both useful to know and important to get right: while many Potterton parts cross-reference to Baxi equivalents, some components are Potterton-specific.
We stock genuine OEM Potterton spare parts for the Promax, Titanium, and older Suprima, System 50/60, and Profile series, with clear labelling of cross-reference parts where applicable.
Key Boiler Ranges
Potterton Promax
The Potterton Promax is the current mainstream range — Promax Combi, Promax System HE, and Promax Store. The Promax combi uses a combustion system, PCB, and gas valve that share significant architecture with the Baxi Platinum range.
Potterton Titanium
Potterton’s current premium combi, with a broader output range (24kW to 48kW). The Titanium’s heat exchanger design differs from the Promax.
Potterton Suprima (Legacy Regular Boiler)
The Suprima was one of Potterton’s most popular heat-only boilers, widely installed in the 1980s and 1990s. The Suprima used a cast iron heat exchanger — a robust but now obsolete design. Parts are increasingly difficult to source. Call to confirm before ordering.
Potterton System 50, System 60, and Performa Series (Legacy)
Older sealed system boilers, widely installed in the 1990s and 2000s. Parts are available for most service requirements.
Most-Searched Potterton Parts
PCB: The Promax PCB shares architecture with Baxi Platinum PCBs — confirm specific model cross-reference before ordering.
Pump Assembly: Potterton Promax and Titanium pumps are Grundfos-based, consistent with the Baxi group approach.
Gas Valve: The Promax uses a Honeywell-type modulating gas valve — the same valve series used in Baxi Platinum models. Gas valve replacement must be carried out by a Gas Safe engineer.
Thermocouple: Older Potterton models (Suprima, System series) used thermocouples rather than electronic flame sensing. The thermocouple generates a small electrical current from the pilot flame to hold open the main gas valve. A failed thermocouple causes the boiler to shut down after lighting.
Thermocouples are one of the most straightforward heating system repairs — compatible thermocouples can be fitted with a simple spanner.
Ignition Electrode and Lead: Potterton’s spark ignition system uses an electrode and lead that are service items. Inspect at every annual service.
Potterton Fault Codes (Promax Range)
L1 — High Limit Thermostat Lockout
The boiler has reached its high-limit temperature and locked out. Same causes as Baxi E110 — failed pump, blocked heat exchanger, scale accumulation.
EA — Ignition Failure (Promax with display)
Mirror of Worcester Bosch EA on models with a fault code display. Causes: ignition electrode, ignition lead, gas valve, PCB.
Potterton/Baxi Cross-Reference Notes
| Potterton Model | Component | Baxi Equivalent |
|---|---|---|
| Promax Combi 24-32 | PCB | Baxi Platinum Combi 24-33 PCB (confirm GC number) |
| Promax Combi | Pump assembly | Baxi Platinum pump (confirm series) |
| Promax Combi | Gas valve | Baxi Platinum gas valve (confirm modulation spec) |
Important: Always use the GC (Gas Council) number from the boiler’s data plate to confirm part compatibility.
Working with Older Potterton Systems
Older Potterton boilers — particularly the Suprima and System series — have outlasted their expected service life and are finding it harder to source certified replacement parts. In many cases, the most cost-effective solution for a significantly aged Potterton is replacement rather than repair.
If you’re assessing whether to repair or replace an older Potterton, our helpline can advise on parts availability: 0330 124 5678.
Compatible Potterton Models
Promax Combi 24, 28, 32; Promax System HE 12, 18, 24; Promax Store 12, 14; Titanium 24, 28, 33, 40, 48; Suprima 30L, 40, 50, 60, 70, 80 (legacy); System 50, 60 (legacy); Profile Combi 80e, 100e (legacy); Performa 24, 28 (legacy combi).
Need a Potterton Engineer Near You?
Our Recommended Installers have experience with the full Potterton range and Baxi group products:
- HGB Heating Kent — Gas Safe engineers, Kent and Medway. Potterton and Baxi specialists.
- Boiler Sense — Certified boiler specialists, Kent and South East London.