How to replace the power cable in your calorifer

Set the heater on a stable, well-lit surface and keep small screws in a safe place.

Have a screwdriver, pliers, wire stripper, utility knife, multimeter and closed wire connectors ready.

Undo the four flat-head screws on the casing with a flat screwdriver.

Slide the housing away to expose the motor, thermostat, switch and wiring.

Use a phone to photograph every wire before loosening anything.

Unscrew the strain-relief clamp that grips the cable inside the heater.

Loosen the terminals or connectors and pull the damaged cable completely out of the appliance.

Set the multimeter to continuity mode so it beeps when a circuit is complete.

Probe each conductor from plug pin to wire end; a tone means good continuity.

Slide the plastic strain-relief sleeve off the old lead and keep it for the new cable.

Push the sleeve onto the replacement cable in the same orientation before any wiring work.

Peel off the loosened jacket to reveal the three inner conductors without nicking their insulation.

Strip a short section of insulation from each conductor using wire strippers for an even finish.

Break off the required number of closed wire connectors from the strip.

Match conductors: the old black phase becomes the new brown, and the blue neutral stays blue.

Twist groups of wires together tightly with pliers before inserting them into the connector.

Hold the wires firmly inside the connector while tightening the screw so nothing backs out.

Lay the new cable into its original path and seat the strain-relief sleeve in its slot.

Tighten the strain-relief screws so the cable cannot be pulled out but is not crushed.

Return the thermostat knob and power selector switch to their original positions.

Plug the heater in and cycle through cold and warm settings to confirm the fan and elements operate.

Verify continuous operation without flicker or smell, showing the cable replacement is successful.