50 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-044-64 | ecoTEC plus 630 VU GB 306/5-5 | 2012–2015 |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Tap any card for details
Your boiler's main electronic control board has temporarily lost connection with the display screen, meaning the system cannot coordinate heating or hot water.
Your boiler has recorded a minor system event or the error memory needs clearing, which usually does not affect its operation.
Your boiler has lost the connection to the sensor that monitors the temperature of the water returning to the unit, causing it to stop working for safety reasons.
Your boiler has detected a communication issue with the built-in hot water storage cylinder temperature sensor.
Your boiler has lost communication with the built-in hot water storage tank sensor, which means it may struggle to provide consistent hot water.
Your boiler has stopped working because one of its internal sensors has developed an electrical fault and can no longer measure the temperature of the water leaving the unit.
Your boiler has detected an electrical fault with the sensor that monitors water returning from your radiators, causing the system to shut down for safety.
Your boiler has detected an electrical wiring or sensor fault related to how it heats your hot water cylinder.
Your boiler has detected a faulty electrical reading from a temperature sensor responsible for monitoring your hot water.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage or overheating.
Your boiler has automatically switched off because the water pressure inside the system has dropped too low to run safely.
Your boiler has detected that the water inside it is heating up or moving much faster than expected, so it has shut itself down to prevent any damage.
Your boiler has detected that the water inside it is heating up much faster than it safely should, causing it to shut down to prevent damage.
Your boiler has detected that the gases it is producing are too hot to be safe, so it has automatically shut down to prevent damage.
Your boiler is unable to open the internal valve that supplies gas to the burner, meaning it cannot ignite to provide heat or hot water.
Your boiler has detected a signal that suggests a flame is present even when the burner is turned off, causing it to shut down for your safety.
Your boiler is trying to start but cannot get the flame to light or stay lit.
Your boiler was working but has suddenly turned off because the flame has gone out and it cannot manage to relight itself.
Your boiler has detected that the internal fan responsible for safely venting exhaust gases is not spinning, so it has shut down to prevent unsafe operation.
Your boiler has detected a blockage or issue with the pipe that brings in fresh air and removes exhaust gases.
Your boiler has lost its memory of which specific model it is, meaning it cannot operate safely without professional reconfiguration.
Your boiler has lost its internal communication signal, meaning the main control board and internal components can no longer properly talk to each other.
Your boiler has lost communication with a sensor that monitors the flow of air and gas, so it has safely shut down to prevent incorrect operation.
Your boiler has detected an issue with the gas flow, meaning it cannot safely ignite or maintain a flame to heat your home.
Your boiler has temporarily stopped working because it is not detecting enough gas supply to safely light the flame.
Your boiler has detected an issue with how it regulates the flow of gas and air inside, so it has temporarily locked itself out for safety.
Your boiler has detected an issue while trying to operate safely in its high-performance mode, so it has temporarily locked itself out to prevent any potential risks.
Your boiler has detected an electrical fault with the valve that controls the gas supply, meaning it has safely locked itself out to prevent unsafe operation.
Your boiler has detected an issue where the gas supply is not shutting off as quickly as it should, which requires a professional gas engineer to inspect for safety.
Your boiler's internal computer brain has developed a memory error and can no longer process the information it needs to run safely.
Your boiler has detected a temperature sensor or electronic control error, so it has safely shut down to prevent damage.
Your boiler has detected that its main electronic control board is overheating or experiencing a serious temperature fault.
Your boiler has detected an internal electronic problem with how it reads the flame signal, meaning it has safely shut down to prevent unsafe operation.
Your boiler has temporarily shut down because the flame burning inside it is flickering or becoming unstable.
Your boiler's electronic control board has lost its identity settings and can no longer recognize which specific model it is installed in.
Your boiler has temporarily stopped working because it is receiving an incorrect temperature reading from one of its internal sensors.
Your boiler has detected an inconsistent temperature reading between its internal sensors, which stops it from running safely.
Your boiler is not receiving a proper signal from its water pressure sensor, meaning it cannot accurately check the water level inside the system.
Your boiler has detected an electrical reading from the water pressure sensor that is too high, meaning it cannot safely monitor the system pressure.
Your boiler has detected a pressure drop or a problem with the water pump starting up, so it has shut down to protect itself.
Your boiler has automatically shut down because a safety device detected that the main part of the boiler has become dangerously hot.
Your boiler has detected an issue with the system that removes waste water or controls the exhaust gases, causing it to lock out for safety.
Your boiler is having trouble communicating with the external controls or hot water system, which is preventing it from heating your water correctly.
Your boiler has detected that the water inside is not heating up or moving properly when the burner tries to start.
Your boiler has detected an unusual temperature difference between its internal pipes, usually because the monitoring sensors are misread, incorrectly attached, or recently swapped during maintenance.
Your boiler's temperature sensors have been attached to the wrong pipes by mistake, so the system cannot properly measure how water is flowing through it.
Your boiler is having trouble communicating with the separate hot water storage tank, which may result in a loss of hot water.
Your boiler has detected an issue with the type of gas it is receiving, meaning it has shut itself down to prevent unsafe operation.
Your boiler has detected an issue with the gas valve or the way it is communicating, meaning it cannot safely start up to provide heat or hot water.
Your boiler is currently operating normally and is in the process of heating your radiators.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes