BoilerFaultCodes
The most common Sime faults
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the filling loop, which is a silver braided hose or a small valve under the boiler.Open the valve(s) slowly to allow cold mains water into the system until the pressure gauge reads between 1 and 1.5 bar.Close the valve(s) tightly and check that the error code has cleared.
Your boiler has failed to light the gas, meaning your heating and hot water will not work until the system is reset or repaired.
Check that your gas emergency control valve is in the 'on' positionPre-payment meter users should check if they have enough creditPress and hold the 'R' reset button for 5 seconds to restart the ignition sequence
Your boiler has detected that the water pressure inside the system is too low, preventing it from heating your home or water properly.
Locate the external filling loop (usually two silver flexible braided hoses underneath the boiler).Slowly open the valves on the filling loop to allow cold mains water to enter the system.Monitor the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1.0 to 1.5 bar).Close both valves tightly to prevent over-pressurisation.
Your boiler is struggling to push water around your heating system, which is often caused by trapped air, a blockage, or a pump that has stopped working.
Check your boiler pressure gauge and top it up to 1.5 bar if it is below 1 bar.Bleed all radiators in your home to ensure there is no trapped air preventing flow.Ensure all radiator valves are fully open to allow water to circulate freely.
Your boiler has detected that the water pressure is too low, causing it to stop working for safety.
Locate the filling loop (the flexible silver hose usually found under the boiler).Slowly open the one or two small tap valves on the hose until you hear water flowing.Watch the pressure gauge and close the valves tightly once the needle reaches between 1.0 and 1.5 bar.
Your boiler has tried to start but could not detect a flame, likely because gas isn't reaching the burner or the ignition spark is failing.
Press and hold the 'R' or reset button to see if the error clears.Check that your gas meter is in credit and that other gas appliances like a hob are working.Verify that the gas isolation valve under the boiler is fully open.
Your boiler has shut down because it has detected it is getting too hot, often caused by a lack of water flow or trapped air.
Check that the boiler pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolating valves are fully openGently bleed your radiators to release any trapped airPress the 'Reset' button on the control panel
Your boiler has failed to light the gas and has locked itself for safety, which means you currently have no heating or hot water.
Check that your gas meter is topped up with credit and the main gas lever is on.Ensure other gas appliances in your home, like a hob, are working correctly to confirm gas flow.Press and release the 'Reset' button to clear the red light and restart the ignition sequence.
Avoid the next call-out bill
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