Whirlpool washer F42: heater state unknown
F42 (F, then 42) means the control could not tell whether the water heater was on or off.
What F42 means
- Brand
- Whirlpool
- Appliance
- Top-load washer
- Code
- F42
- Documented meaning
- Heater state unknown
- Applies to
- 38 Whirlpool models on 2 platforms
- Can you keep using it?
- No — stop and have it checked
What the washer is detecting
On models with an internal water heater, the control monitors the heater circuit. When the heater state cannot be determined, F and 42 flash.
Causes listed for this condition
In the order the service documentation checks them. Documented causes come from the manufacturer's service documentation for these platforms; possible causes are based on how the system works; unconfirmed marks common assumptions that the documentation does not support.
- Documented A fault in the heater circuit, checked with the heater test.
Safe checks you can make
- Turn the washer off and unplug it if it is not in use.
This stage requires professional testing. Full diagnosis involves hazards such as live line voltage, gas, a sealed refrigerant system or microwave high voltage. Do not attempt it yourself.
What a technician checks
- Runs the heater test.
- Checks the heater circuit and its control.
Typical repairs and cost
Depending on what diagnosis finds, this code can lead to one of these repairs:
| Repair | Typical range | Labor |
|---|---|---|
| Washer main control board replacement | $300–$720 | Moderate |
Typical total ranges for the Las Vegas area, parts and labor included. The final cost depends on diagnosis, the exact model, parts availability and whether other damage is found.
Can you keep using it?
Stop using it until it is checked. Unplug the washer until it is checked. The heater circuit works at line voltage and requires professional testing.
Whirlpool models documented with this code
- WTW6200SW
- WTW6200VW
- WTW6300SB
- WTW6300SG
- WTW6300SW
- WTW6300WW
- WTW6310WW
- WTW6340WW
- WTW6400SW
- WTW6410WW
- WTW6500WW
- WTW6600SB
- WTW6600SG
- WTW6600SW
- WTW6700TU
- WTW6700TW
And 22 more. Use the model lookup to check yours.
Related problems and codes
Other codes documented on the same Whirlpool platforms:
Repair or replace?
A fault code alone rarely justifies replacing a washer. Most F42 repairs involve a single component once diagnosed. Replacement becomes worth considering when the unit is near the end of its typical 10–13-year life and the diagnosed repair is a major one. See the repair-or-replace guide.
Need F42 diagnosed in the Las Vegas area?
We repair Whirlpool, Maytag, KitchenAid, JennAir, Amana and other Whirlpool-family appliances in Las Vegas, Henderson, Summerlin and Boulder City. A model number helps but is never required to book.