23 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Duo-tec 2 Combi
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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 |
|---|---|---|
| 47-075-56 | Duo-tec 2 Combi 33 GA | 2011–2015 |
| 47-075-57 | Duo-tec 2 Combi 40 GA | 2011–2015 |
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.
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Your boiler has lost its connection to the component that controls the fuel supply, meaning it cannot ignite to provide heating or hot water.
Your boiler has detected a communication problem with the part that controls the gas supply, meaning it cannot light safely for heating or hot water.
Your boiler has lost signal from the sensor that monitors the temperature of the water used to heat your radiators.
Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down for safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning from your radiators.
Calibration Required
Your boiler's internal pump is struggling to move water around the system before the burner starts, which often suggests an air lock or a blockage.
Your boiler has switched itself off because it has detected that the water inside has become far too hot.
There is too much water pressure in your boiler system, which has caused the unit to shut down for safety.
Your boiler has stopped working because the water pressure in the system has dropped too low to operate safely.
Your boiler has detected that water is not moving through the system properly, which is causing it to overheat and shut down for safety.
Your boiler has lost its flame while it was running, meaning it has safely shut down because it can no longer heat your water.
Your boiler has shut down because it detected that the exhaust gases are getting too hot, which is a safety feature to prevent damage.
Your boiler has tried to light several times but has failed, which means the flame is either not starting or not staying on.
Your boiler is trying to light but cannot find a gas supply or ignite a flame.
Your boiler has lost its connection to the gas supply or cannot detect gas flow, meaning it cannot ignite to provide heating or hot water.
Your boiler has detected a problem with the fan that safely pushes waste gases out of your home, causing the system to shut down for safety.
Your boiler has detected that water isn't moving through the system properly, which is causing it to overheat too quickly and shut down for safety.
Your boiler is struggling to provide hot water because the temperature sensor responsible for tracking it has developed a fault.
Your boiler thinks there is a flame present when there shouldn't be, causing it to shut down for safety.
Your boiler has stopped working because the water pressure in the system has dropped too low.
Your boiler started to heat up but the flame went out unexpectedly while it was running.
Your boiler is failing to ignite because it is not receiving enough gas or cannot detect a flame.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes