BoilerFaultCodesThe 6 most common faults
01
E119 High DIY-safe
Your boiler has temporarily stopped working because the internal water pressure has dropped too low to operate safely.
What to try first
Locate the filling loop (two valves and a silver braided hose) underneath your boiler.Open both valves slowly to let mains water into the system, and watch the pressure gauge on the front of the boiler.Stop filling when the needle reaches the green zone (usually between 1.0 and 1.5 bar) and firmly close both valves.
02
E125 High DIY-safe
Your boiler is struggling to move water around the system effectively, which is causing it to shut down to prevent overheating.
What to try first
Check that your radiator valves are fully openEnsure your boiler pressure is between 1.0 and 1.5 bar on the gaugeGently bleed your radiators to remove any trapped air pockets
03
E133 High Engineer
Your boiler has failed to ignite or lost its flame, meaning it has temporarily stopped working to keep you safe.
Full guide for E13304
E20 High Engineer
Your boiler has stopped working because a sensor that monitors the temperature of the water returning to the unit has developed a fault.
Full guide for E2005
E28 High Engineer
Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, causing it to stop running for safety.
Full guide for E2806
E130 High Engineer
Your boiler has sensed that the exhaust gases are getting too hot and has shut down as a safety precaution to prevent damage.
Full guide for E130on the Potterton Gold Combi
Pressure relief valvePressure sensorExpansion vesselCirculating PumpDiverter ValveFlow Temperature Sensor
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Potterton shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue
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