BoilerFaultCodesThe 6 most common faults
01
Low system pressure High DIY-safe
Your central heating system has lost the water pressure it needs to circulate heat, which will prevent the boiler from running until it is topped back up.
What to try first
Locate the filling loop (usually a silver flexible hose) underneath the boiler or near the heating pipes.Open the valves at both ends of the hose to let mains water into the system.Monitor the pressure gauge on the front of the boiler until the needle reaches 1.5 bar, then securely close both valves.
02
Reversed Polarity High Engineer
Your boiler has detected that the electrical supply is connected back-to-front, which is a common issue often caused by recent electrical work or a faulty wall plug.
Full guide for Reversed Polarity03
Lockout High Engineer
Your boiler has detected a safety issue and has shut itself down to prevent damage, meaning it needs a simple manual reset to try and start up again.
Full guide for Lockout04
Red Neon High Engineer
Your boiler has detected a problem and safely shut itself down to prevent damage, meaning you currently have no heating or hot water.
Full guide for Red Neon05
Flame Emergency Engineer
Your boiler is flagging that it detects a flame when it shouldn't be, which could indicate a sensor fault or an issue with the internal gas valve failing to shut off correctly.
Full guide for Flame06
Permanent Live 'On' Low DIY-safe
Your boiler is currently reporting that it is receiving a constant electrical signal to start heating, which is a normal indicator light used by engineers to check that the internal wiring is receiving power.
What to try first
Check that your room thermostat or programmer is set to 'On' or 'Auto'Verify that the temperature setting on the thermostat is higher than the current room temperatureNo action is required if the boiler is operating normally, as this is a status indicator
on the Potterton Ultra 2 50 DV
Filling loopPressure relief valvePressure gaugeMain plugFused spurIgnition Electrode
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