Zenith Dishwasher Error Code F5

The F5 error code on a Zenith dishwasher indicates that the control system has detected water temperature exceeding the expected upper threshold during a wash or rinse cycle. The dishwasher's temperature monitoring circuit, which relies on a thermistor or temperature sensor submerged in the wash tub, continuously reports water temperature to the main control board. When that reported temperature climbs above the programmed safety limit, the board triggers F5 and typically halts the cycle to prevent potential damage to dishes, internal components, or the tub itself.

The most frequent cause of F5 is a faulty thermistor that is sending inaccurate high readings to the control board, even when actual water temperature is within normal range. However, a genuinely overheating heating element, a malfunctioning control board that fails to regulate the element's on-time, or issues with the water inlet supplying water that is already very hot from the household supply can also produce this fault. In some cases, a wiring harness problem between the sensor and the board can cause erratic or false high-temperature signals.

Proper diagnosis involves checking the thermistor's resistance output at operating temperature and comparing it against the expected specification range for the sensor type used. The heating element should also be inspected for signs of continuous energization or physical damage. Verifying that the incoming hot water supply temperature is within a normal household range, typically below 60 degrees Celsius, is also a useful early step before replacing components.