Water heater runs but hot water temperature fluctuates or is not hot enough at taps.

Safety: Turn off power and close water isolation valves before removing any water-carrying components.

Steps:

• Check tap flow rate: If water flow is very high, the heater may not be able to raise temperature sufficiently. Partially close the hot tap to reduce flow and see if temperature stabilises.
• Clean cold inlet filter: Remove and clean the cold water inlet filter to ensure proper flow through the heater.
• Descale plate heat exchanger (user-level): If accessible and with isolation valves fitted, remove the plate heat exchanger and soak in a manufacturer-approved descaling solution. Rinse thoroughly before refitting.
• Verify temperature setting: Ensure the DHW temperature setpoint on the control panel is correctly adjusted.

Note: Severe scaling or sensor faults may require professional service and part replacement.