F3H — Humidity Sensor Out of Range
Whirlpool lists F3H as a possible problem with the humidity sensor (called the humidity thermistor on over-the-range models) or its wiring.
- Keep using it?
- Yes, with caution
- DIY difficulty
- Moderate
- Verified against
- producthelp.whirlpool.com ↗ Whirlpool Product Help: F3H
How to fix it
- Reset power: turn off the circuit breaker(s) for one minute, turn them back on, and watch the microwave for one minute to see whether the code returns.
- Try a manual cook cycle; if F3H returns, schedule service. Do not open the microwave cabinet or test parts inside it: it holds a high-voltage capacitor that can stay charged after unplugging.
Why it happens
Typical signs: F3H or F3-H on the display · Sensor Cook / Sensor Reheat / Popcorn fails immediately · Manual time cooking still works · F3H appears partway through a sensor-cook cycle
- Failed humidity sensor The most common cause — sensors degrade from steam and grease.
- Grease film on the sensor face A coated sensor reads incorrectly even when electrically fine.
- Loose wiring or connector at the sensor or control Vibration over the range can back a small connector out.
Parts you may need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
- Whirlpool microwave humidity sensor Common replacementAmazon →
More Whirlpool microwave codes
Frequently asked questions
What does the F3H code mean on a Whirlpool microwave?
Whirlpool lists F3H as a possible problem with the humidity sensor (called the humidity thermistor on over-the-range models) or its wiring.
What causes the F3H code on a Whirlpool microwave?
Failed humidity sensor: The most common cause — sensors degrade from steam and grease. Grease film on the sensor face: A coated sensor reads incorrectly even when electrically fine. Loose wiring or connector at the sensor or control: Vibration over the range can back a small connector out.
Is it safe to keep using a Whirlpool microwave with a F3H error?
Yes, with caution. This is rated a moderate-severity fault.
How do I fix F3H on a Whirlpool microwave?
Reset power: turn off the circuit breaker(s) for one minute, turn them back on, and watch the microwave for one minute to see whether the code returns. Try a manual cook cycle; if F3H returns, schedule service. Do not open the microwave cabinet or test parts inside it: it holds a high-voltage capacitor that can stay charged after unplugging.
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: producthelp.whirlpool.com.