BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the one or two taps/valves until you hear water entering the system.Watch the pressure gauge and close the taps once it reaches between 1.0 and 1.5 bar.
Your boiler started to heat up but the flame unexpectedly went out, causing the system to stop working for safety.
Check that your gas prepay meter has creditCheck if other gas appliances, like a cooker, are workingReset the boiler by turning the selector switch to 'R' for five seconds
Your boiler has tried to light several times but cannot establish a flame, meaning you currently have no heating or hot water.
Check that your gas prepayment meter has credit (if applicable).Ensure your external gas emergency control valve is in the 'on' position.Press and hold the 'R' Reset button for five seconds to attempt a restart.If it is freezing outside, check that the plastic condensate pipe hasn't frozen solid.
Your boiler has stopped working because the water pressure inside the heating system has dropped below the minimum level required to operate safely.
Locate the external filling loop, which is a flexible braided hose connected to two valves under your boiler.Open the valves slowly to allow mains water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close both valves firmly and ensure the filling loop is disconnected if it is a removable type.
Your boiler has lost its connection to the gas supply mechanism, meaning it cannot safely ignite to provide heating or hot water.
Full guide for 09Your boiler has lost the ability to accurately measure the temperature of the water circulating to your radiators, causing it to shut down for safety.
Full guide for 20on the Potterton Promax Ultra Combi ErP
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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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