E13 error, unit locks out after running for a short period

Safety: Overheat conditions can be hazardous. If water is boiling or venting, isolate power and heat source immediately and allow the system to cool fully.

Steps:

• Check pump speed: Many circulation pumps have adjustable speed settings. Ensure the pump is set to the speed recommended by Gledhill for your model.
• Bleed air: Air locks can cause poor circulation and hot spots. Bleed radiators and any automatic air vents on the primary circuit.
• Inspect sensor location: Confirm the overheat/store sensor is in the correct pocket and not touching bare metal outside the intended sensing area.
• Descale (if applicable): In hard water areas, heavy scale around the sensor pocket can cause false high readings. A professional may need to descale the affected area or replace the pocket/immersion.

Warning: Repeated E13 events should be investigated by a heating engineer to prevent damage to the cylinder or connected boiler.