Oven display shows F4 and oven will not heat or shuts down shortly after starting

Safety: Disconnect from mains. Metal edges behind panels can be sharp; wear cut-resistant gloves.

• Visual inspection: Remove the top and rear covers to access the cooling fan assembly (usually above or behind the oven cavity). Look for signs of overheating, melted wiring, or obstructions (insulation, debris) in the fan blades.
• Test fan operation: With power restored briefly, start the oven and listen for the cooling fan. If it does not run within a few minutes, isolate power again and test the fan motor for continuity with a multimeter. An open circuit indicates a failed motor.
• Check fan thermostat: Some Belling models use a cooling fan thermostat to switch the fan on. Locate this thermostat on the top panel or near the flue. Test for continuity when warm (you can gently warm it with a hair dryer while monitoring with a meter). Replace if it does not close as it heats.
• Clean vents: Ensure front fascia vents and rear outlet vents are clear of grease and dust. Blocked vents can cause F4 even with a working fan.
• PCB fault: If fan and thermostat are good but F4 persists, the control PCB may not be driving the fan correctly or may be misreading temperature. PCB replacement is a specialist job.