Wolf CSO Steam Oven Code E43 / F8: neutral relay K1 or K2 stuck

What E43 / F8 means

On Wolf CSO convection steam ovens, including the CSO30 series, E43 with F8 means neutral relay K1 or K2 is stuck. A stuck neutral relay keeps a switching path closed when it should open, so the oven shows the pair and stops. The owner sees the display message and an oven that may not start another cycle.

Common causes of E43 / F8

Neutral relay K1 stuck
Neutral relay K2 stuck

✓ One safe check you can try

1. Shut off the oven's breaker. 2. Wait one minute and restore power. 3. Check whether the display clears. 4. When E43 / F8 returns, keep the oven off and phone us. Do not open the control area or test any wiring.

! Why to stop there

A stuck relay is a safety item that should not be bypassed.
Relay K1 versus K2 needs board-level identification.
We quote in writing first, and repairs have a 30-day warranty.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Steam Oven codes

F9Wolf CSO Steam Oven Code F9: cooking space not sealed U0Wolf CSO Steam Oven Code U0: neutral or overvoltage problem U1Wolf CSO Steam Oven Code U1: L2 supply problem U2Wolf CSO Steam Oven Code U2: mains undervoltage Boiler scaled upWolf Convection Steam Oven Message Boiler scaled up: Descale required E26Wolf Convection Steam Oven Code E26: Climate sensor problem E87Wolf 24-Inch E Series Code E87: Exhaust slide valve jammed or shorted E42Wolf Convection Steam Oven Code E42: Water temperature sensor error

E43 / F8E43 / F8 questions

Will E43 / F8 clear after a reset?

Possibly if a relay freed itself, but it often returns. A stuck relay needs replacement or board service.

What are K1 and K2?

They are neutral relays on the oven's relay board. The code says one of the two is stuck.

Is the oven safe to use?

We recommend not using it until it is checked, since a relay that sticks can affect how the oven switches power.