BoilerFaultCodesThe 6 most common faults
Your boiler has detected that the water pressure in your heating system is too low to operate safely, so it has shut down to protect its internal components.
Locate the external filling loop, which is usually a small silver braided hose with one or two valves connecting your boiler to the mains water supply.Open the valve(s) slowly to allow water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve(s) firmly and wait for the boiler to detect the pressure increase, often requiring a manual reset.
Your boiler's computer is experiencing a temporary glitch and needs to be restarted to try and clear the error.
Locate the reset button on the front control panelPress and hold the reset button for 3 to 5 secondsWait 5 minutes for the boiler to cycle and see if the code clears
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the filling loop (usually a silver braided hose with one or two valves) underneath your boiler.Open the valve(s) slowly to allow mains water to enter the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve(s) tightly to prevent over-pressurising the system.
Your boiler has stopped working because the water level inside the heating system has dropped below the required amount.
Locate the external filling loop, which is a silver braided hose connected to your boiler pipes.Open the valves at both ends of the hose to let mains water enter the system.Watch the pressure gauge on the front of the boiler and close the valves once the needle reaches 1.5 bar.Check that the boiler restarts and the fault code clears.
Your boiler has automatically shut down because the internal water pressure has climbed too high and exceeded safe operating limits.
Locate a radiator in your home with a bleed valve.Use a radiator key to open the valve slightly and drain a small amount of water into a container.Monitor the pressure gauge on the front of the boiler until it drops back into the green zone (typically 1.0 to 1.5 bar).Close the radiator valve once the pressure is correct.
Your boiler has attempted to start several times but cannot get the flame to stay lit, so it has locked itself for safety.
Full guide for A01on the Potterton Promax 15 & 24
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