BoilerFaultCodes
The most common Warmhaus faults
Your boiler has detected that the water pressure in the system is too low or the pressure sensor settings are incorrect, causing the unit to stop working.
Why it happens: This fault occurs when the boiler detects that there isn't enough water pressure to safely circulate heat around your home. The most common reason is a slow leak in the radiator system or air being released from the pipework, causing the pressure to drop below the minimum safety threshold.
Check the pressure gauge; it should ideally be between 1.0 and 1.5 bar.Locate the filling loop (usually a silver flexible hose) under the boiler.Open both valves slowly to allow water into the system until the gauge reaches 1.2 bar, then close them tightly.
Your boiler has too much water in the system, causing it to shut down to prevent damage from excessive pressure.
Why it happens: This fault occurs when the water pressure inside your heating system exceeds the safe operating limit. The most common reason is that the filling loop was left slightly open after topping up the system, or the internal expansion vessel has lost its air charge and can no longer balance the pressure changes as the water heats up. In some cases, a leaking internal component might be allowing fresh mains water to constantly enter the system.
Check that the filling loop valves are fully closedBleed water from a radiator using a bleed key to reduce pressureMonitor the pressure gauge to ensure it returns to between 1.0 and 1.5 barReset the boiler once the pressure is stabilised
Your boiler is not starting because it cannot light the gas flame needed to heat your water.
Why it happens: This fault occurs when the boiler attempts to start but cannot detect a flame after several attempts. It is usually caused by a lack of gas reaching the burner, a faulty spark plug that cannot ignite the gas, or a sensor that fails to tell the boiler that a flame is present.
Check that your gas emergency control valve (lever) is in the 'on' position.If you have a prepay gas meter, ensure you have sufficient credit.Check if other gas appliances in your home, like a hob, are working correctly.Press and hold the 'R' or reset button to see if the boiler restarts.
Your boiler is not starting because it cannot light the gas flame needed to heat your water.
Why it happens: This fault occurs when the boiler attempts to start but cannot detect a flame after several attempts. It is usually caused by a lack of gas reaching the burner, a faulty spark plug that cannot ignite the gas, or a sensor that fails to tell the boiler that a flame is present.
Check that your gas emergency control valve (lever) is in the 'on' position.If you have a prepay gas meter, ensure you have sufficient credit.Check if other gas appliances in your home, like a hob, are working correctly.Press and hold the 'R' or reset button to see if the boiler restarts.
Your boiler has shut down because it has detected that the water inside has become dangerously hot.
Why it happens: This fault occurs when the internal water temperature rises too rapidly or exceeds safe limits, triggering a safety sensor to shut the system down to prevent damage. The most common reasons are a pump failure that stops water from moving or a blockage in the heat exchanger that traps heat inside the unit.
Check that your radiator valves are open to allow water to flow.Ensure your system water pressure is between 1.0 and 1.5 bar.Press and hold the 'R' or Reset button for a few seconds to restart the boiler.
Your boiler has detected that water is not moving through the system correctly, causing a temperature imbalance that has shut the unit down for safety.
Why it happens: This fault occurs when the boiler's internal sensors detect that water is heating up too quickly or not flowing away from the heat exchanger fast enough. The most common reasons are a failed or blocked circulation pump, air trapped in the system, or a buildup of sludge and debris that has restricted the internal pipework. Because the heat cannot be moved into your radiators effectively, the boiler shuts down to prevent the unit from overheating.
Check that your boiler pressure is between 1.0 and 1.5 bar on the gauge.Ensure all radiator valves and isolation valves under the boiler are fully open.Gently bleed your radiators to remove any trapped air pockets.Reset the boiler by pressing the 'R' or Reset button.
Your boiler has detected that water is not moving through the system correctly, causing a temperature imbalance that has shut the unit down for safety.
Why it happens: This fault occurs when the boiler's internal sensors detect that water is heating up too quickly or not flowing away from the heat exchanger fast enough. The most common reasons are a failed or blocked circulation pump, air trapped in the system, or a buildup of sludge and debris that has restricted the internal pipework. Because the heat cannot be moved into your radiators effectively, the boiler shuts down to prevent the unit from overheating.
Check that your boiler pressure is between 1.0 and 1.5 bar on the gauge.Ensure all radiator valves and isolation valves under the boiler are fully open.Gently bleed your radiators to remove any trapped air pockets.Reset the boiler by pressing the 'R' or Reset button.
Your boiler has detected an issue with the stability of the electrical power supply coming into your home.
Why it happens: This fault occurs when the boiler's internal computer detects that the incoming electrical supply is not staying at a steady frequency. The most common reason is an unstable local power grid or interference from other high-powered appliances in your home that are distorting the electrical signal. If the power supply is consistent, it usually indicates that the boiler's main control board has become oversensitive or damaged and can no longer process the electricity correctly.
Turn the boiler off using the power button or at the fused spur switchWait for 60 secondsTurn the power back on and check if the code clears as the local grid stabilizes