BoilerFaultCodesGlow-worm ECO Fault Code
The Glow-worm ECO fault code means: your boiler is currently set to an energy-saving mode because your hot water temperature has dropped below 50°c, often occurring after a high demand for water.. It appears on 2 Glow-worm models in our database.
Technical description: Will be displayed when domestic hot water temperature is less than 50oC
What causes the Glow-worm ECO fault?
This message appears when your boiler’s storage tank has been emptied of its hot water, typically after someone has taken a long bath or shower. To save energy, the boiler temporarily signals that it is working to reheat the water back up to your desired temperature. It is a normal part of the system's operation and simply indicates that the cylinder is currently recovering.
This occurs more frequently in winter when the incoming mains water is much colder, meaning the boiler has to work harder and longer to reheat the tank.
DIY fix possible
Wait for the boiler to reheat the water cylinder naturally.Press the 'ECO' button to toggle the mode off if you require hotter water immediately.Check that the hot water temperature setting on the control panel hasn't been turned down too low.
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Gas Safe Register →Glow-worm models that show the ECO fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm ECO fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026