W10225581 Genuine Defrost Bimetal Thermostat for Whirlpool Fridges and Freezers, Defrost Termination Switch

W10225581 is a genuine Whirlpool defrost bimetal, the thermostat that controls the defrost cycle in frost-free refrigerators. It clips onto the evaporator coil behind the freezer panel and cuts power to the defrost heater once the ice has melted. We don't have a compatible model list on file, so compare the number on your old part, or check the model and serial number on the label inside your fridge, before ordering.

Signs of a faulty defrost bimetal

During a defrost cycle a heater warms the evaporator to clear frost, and the bimetal switches it off at a set temperature. If the bimetal fails open, the heater never runs and ice builds up on the evaporator until air can't pass through. The freezer may still feel cold while the fridge section warms up, and frost can show on the back panel. If it sticks closed, the heater may run too long, leaving drips or melted ice. A continuity test at freezing temperature confirms the fault.

Part details

• Genuine Whirlpool part W10225581
• Defrost bimetal thermostat
• Controls the defrost heater in frost-free fridges
• No models on file

Replacing the defrost bimetal

Unplug the fridge or switch it off at the wall, and move the food into an esky. Remove the freezer back panel to reach the evaporator, taking care not to puncture the coil with tools, and let any heavy ice melt first. The bimetal is usually clipped to the coil tubing and joined with a plug or splices. Fit the new one firmly to the same tube so it senses the right temperature.

Questions about this part

My freezer is fine but the fridge is warm. Could it be this part?

It's a common cause. If the evaporator ices over, cold air can't reach the fridge section. Look for heavy frost behind the freezer panel. The defrost heater and the defrost control can cause the same symptom, so test all three.