13 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Promax System HE Plus
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 |
|---|---|---|
| 41-595-39 | Promax FSB 30 HE | 2006–2015 |
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Your boiler has lost the ability to accurately measure the water temperature, so it has safely shut itself down to prevent it from overheating.
Your boiler is failing to detect that water is circulating through the system, so it has shut down to prevent internal damage.
Your boiler has detected that it has become dangerously overheated and has shut itself down to prevent damage.
Your boiler's fan, which safely clears exhaust gases from the unit, has stopped spinning correctly and prevented the system from firing up.
Your boiler has tried to light but failed to stay on, meaning the system has shut down for safety until it is reset or repaired.
Your boiler has detected that there is not enough water flowing through it, so it has safely shut itself down to prevent damage to its internal components.
Your boiler has failed to start after several attempts because it cannot safely light its internal flame.
Your boiler has stopped working because the internal fan, which clears exhaust gases, is failing to start or run correctly.
Your boiler has stopped working because a sensor that measures the water temperature is providing incorrect information, causing the system to shut down for safety.
Your boiler has stopped working because the pipe that drains away waste water is blocked, causing the system to temporarily shut down to prevent internal damage.
Your boiler has shut down because water intended for your drain is backing up and has triggered a safety sensor.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage to its internal components.
Your boiler's internal temperature sensor has stopped sending a reliable signal, which means the system cannot safely monitor how hot the water is getting.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes