F4
Russell Hobbs
Heater Overheat / Dry-Fire Protection
F4 error and no heated water; unit otherwise operates normally.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Running heater with empty tank, Limescale restricting flow through heater, Faulty overheat thermostat, Poor water flow from pump
How to Fix / Troubleshooting
Safety first: Unplug and allow the unit to cool fully before working on the heater or water system.
- Refill tank: Ensure the clean water tank is full and correctly seated. Never run the heater with an empty tank.
- Descale heater: Run a descaling cycle using a manufacturer-approved descaler to remove limescale from the heater and internal hoses. Flush thoroughly afterwards.
- Check flow: With heater off, verify that spray output is strong. Weak flow indicates a pump or blockage issue that can cause heater overheat.
- Thermostat check (advanced): The heater assembly may have a resettable thermostat or thermal fuse. Inspect for a small red or button-type reset; press gently if present. If a thermal fuse is open, the heater assembly must be replaced.
- If F4 persists: Replace the in-line heater assembly including thermostat/thermal fuse.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
In-line Heater Assembly
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements