Potterton Boiler Fault Codes Explained

The Promax code table

Potterton boilers are made by Baxi Heating, and the Promax range uses the same display logic as Baxi’s Duo-tec. The user guide lists these codes. If you are seeing a bare E1 on a Potterton, it is the first half of one of the three-digit codes.

• E20: heating temperature sensor fault.
• E28: flue sensor fault, which can also mean a blocked flue or condensate drain.
• E50: hot water temperature sensor fault.
• E110: safety thermostat has tripped on overheat.
• E119: water pressure below 0.5 bar.
• E125: no circulation in the heating circuit.
• E130: flue sensor has tripped on overheat.
• E133: gas supply interrupted or no flame detected.
• E160: fan or fan wiring fault.

What you can do and what you cannot

For E119, top the system up with the blue-handled filling loop under the boiler to 1 to 1.5 bar; the boiler restarts on its own. The same low-pressure causes and checks apply as on a Baxi showing E119. For E110, E130 and E133, turn the selector to reset and hold it for at least five seconds, once. E20, E28, E50, E125 and E160 are listed by Potterton as faulty components, so a reset will not help, although in a frost it is worth thawing the condensate pipe before you assume E28 is a sensor.

Other Potterton models, older and newer, use different displays and code lists. If what you see does not match the table, go by the user guide that came with your boiler.

If you smell gas, do not reset anything. Open windows, turn off the gas at the meter if it is safe to reach, use no switches, and call the National Gas Emergency Service on 0800 111 999 from outside.

Getting a Potterton fixed

If a code keeps coming back, or names a part, book an emergency boiler repair. The visit starts with the £60 call-out at any hour, and the repair price is agreed with you on site before any work starts. Gas work is carried out by Gas Safe registered engineers. For lockouts that keep returning, our explainer on boiler ignition lockout covers the usual causes.