Westinghouse F109

Westinghouse error code F109 indicates: Westinghouse Elevate / Multi-Function Built-in Oven: Cavity temperature sensor fault F109; electronic board detects open circuit or shorted PT500 / PT1000 temperature sensor..

The primary root cause for Westinghouse code F109 is: On Westinghouse (Westinghouse Elevate / Multi-Function Built-in Oven) models: Open platinum thermal sensor element in oven back wall (nominal ~540 Ω for PT500 or ~1080 Ω for PT1000 at 20°C), broken wiring lead, or pinched heat-resistant cable..

To resolve error code F109: Disconnect oven mains. Access rear panel cavity sensor harness. Measure resistance with multimeter (PT500 reads ~540 Ω at 20°C; PT1000 reads ~1080 Ω at 20°C). Press Start/Pause together with Temp button for 5 seconds to exit service diagnostic mode and clear persistent EEPROM alarm.

Resetting power (unplugging for 5–10 minutes) clears temporary memory errors. However, if Westinghouse code F109 persists, the physical component causing On Westinghouse (Westinghouse Elevate / Multi-Function Built-in Oven) models: Open platinum thermal sensor element in oven back wall (nominal ~540 Ω for PT500 or ~1080 Ω for PT1000 at 20°C), broken wiring lead, or pinched heat-resistant cable. must be inspected or replaced.

Set a digital multimeter to ohms (Ω). Disconnect power and test NTC Temperature Sensor Probe (Thermistor) across Across sensor pins 1-2 (unplugged harness). Expected nominal reading is 4.8kΩ–12kΩ (at 20°C–25°C). Tolerance: Negative temperature coefficient: resistance drops smoothly when warmed with fingers. OL = open circuit..

Standard electrical safety protocol: 1. Disconnect 230V mains power before opening panels. 2. Verify zero voltage at test points. 3. Allow hot water or heating elements to cool below 30°C before handling.