E4 appears on the display; unit will not start or stops mid-cycle.

Safety: Disconnect from mains and allow the appliance to cool completely.

• Check fan operation: Before disassembly, plug in and start a cycle. Listen for the fan. If E4 appears and the fan never starts, the heater area may overheat quickly. Unplug again.
• Access heater assembly: Remove the rear or top cover to expose the heater, fan, and thermal cut-out (bimetal thermostat).
• Inspect thermal cut-out: Locate the small round or rectangular thermostat clipped or screwed to the heater shroud. Check for discoloration, cracks, or loose mounting.
• Continuity test: With the unit unplugged, disconnect one terminal and test continuity across the thermostat. If it is open at room temperature and not a manual-reset type, it has failed and must be replaced with the correct Russell Hobbs thermal cut-out/thermostat.
• Check fan motor: Spin the fan blades by hand; they should move freely. If stiff or seized, the fan motor may be failing and causing overheating. Replace if necessary.
• Clean dust and grease: Heavy buildup on the heater and fan can trap heat. Clean carefully with a soft brush and vacuum (avoid bending the heater coil).
• Reassemble and test: Refit all covers, ensuring vents are unobstructed. Run a short test cycle and monitor for E4.

If E4 persists with a new thermostat and working fan, the control PCB may be faulty and should be checked by a technician.