Potterton Boiler Fault Codes
Gas Safe registered fault diagnosis for Potterton Titanium, Gold, Promax, and Performa models. E119, E168, E133, E28, E160 — explained with repair costs and South London context.
Understanding Potterton boiler fault codes
Potterton is a long-established British boiler brand, now part of the BDR Thermea Group — the same parent company as Baxi. This means newer Potterton models share fault codes and many components with Baxi, making parts relatively easy to source. Common in South London properties built between 2000–2015. Reion carries out Potterton repairs across all models.
This guide covers the five most commonly searched Potterton fault codes, with technical explanations of what each fault means, what causes it, and what a Gas Safe engineer will do to fix it. Reion Miller (Gas Safe 919881) carries Potterton parts and handles Potterton boiler repairs across South London.
Potterton fault codes explained
Low water pressure
System pressure has dropped below the minimum threshold. The most homeowner-accessible Potterton fault — usually resolved by repressurising via the filling loop to 1.2–1.5 bar.
Ignition lockout
The boiler attempted ignition multiple times but could not establish a stable flame. The most common Potterton fault requiring a Gas Safe engineer. Potterton and Baxi share this code due to BDR Thermea group engineering.
Gas supply fault
The boiler cannot detect a gas supply or the gas valve has not operated correctly. Requires a Gas Safe engineer — do not attempt to reset repeatedly.
No water circulation
The pump is not circulating water through the system, or the flow sensor cannot detect movement. Common on Potterton boilers over 8 years old — the pump wears at the same rate as Baxi equivalents.
Fan / flue fault
The PCB cannot confirm the fan is running at the correct speed, or the air pressure switch has not triggered during the proving sequence.
Potterton boiler fault code table
Extended fault code reference for common Potterton Titanium, Gold, Promax, and Performa models.
| Code | Meaning | Common cause | Action |
|---|---|---|---|
| E119 | Low water pressure | System pressure below 0.5 bar | Repressurise to 1.2–1.5 bar (homeowner safe if no leak) |
| E168 | Ignition lockout | No flame detected after multiple attempts | Gas Safe engineer required |
| E133 | Gas supply fault | No gas or gas valve failure | Gas Safe engineer — do not reset repeatedly |
| E28 | No water circulation | Pump failure, airlock, blocked circuit | Gas Safe engineer required |
| E160 | Fan / APS fault | Fan motor failure, blocked flue, APS failure | Gas Safe engineer required |
| E131 | Gas valve fault | Gas valve not responding correctly | Gas Safe engineer — gas valve replacement likely |
| E110 | Overheating | Limescale, pump failure, blocked circuit | Gas Safe engineer — allow to cool first |
| E125 | Pump overrun / overheat | System overheating, pump running after shutdown | Gas Safe engineer |
| E20 | NTC sensor fault | Flow or return thermistor failure | Gas Safe engineer |
| E50 | DHW sensor fault | Domestic hot water thermistor failure | Gas Safe engineer |
Why Potterton boilers fault more often in London
Potterton boilers are common across South London properties — particularly Wandsworth, Merton, Lewisham, Lambeth, Southwark, and Bromley. The Potterton Gold and Titanium HE combi ranges were widely installed in properties built between 2000 and 2015, meaning many are now reaching the age where component wear becomes common.
Thames Water supplies water with some of the highest calcium concentrations in England. Inside a Potterton boiler, this deposits as limescale on the heat exchanger over years. The result: restricted water flow, ignition faults (E168), overheating (E110), pump failures (E28), and heat exchanger failures that annual servicing would have prevented.
Because Potterton Gold and Titanium models share the same BDR Thermea platform as Baxi, they are subject to the same hard water service intervals and the same failure patterns. Reion recommends fitting a Fernox TF1 or Adey MagnaClean magnetic filter and running an annual service on every Potterton boiler in South London.
Potterton boiler fault code questions
How do I reset a Potterton boiler after a fault code?
Do Potterton and Baxi boilers share fault codes?
Why does my Potterton boiler keep showing fault codes in London?
Can I fix a Potterton boiler fault code myself?
How much does a Potterton boiler repair cost in London?
Potterton fault code showing on your boiler?
Reion is Gas Safe registered (919881), carries Potterton parts, and serves all of South London. Fixed price after the £80 diagnostic — no obligation to proceed.
