Wolf CSOP Plumbed Steam Oven Code E78 / F24: Drain sump sensor issue

What E78 / F24 means

E78, also shown as F24, applies to the plumbed Wolf steam ovens CSOP2450TM and CSOP3050TM. The official meaning relates to draining the plumbed oven: the drain sump level sensor pin is dirty, or there is a short circuit in the drain sump level sensor or in the sensor module. The recommended first step is to flush the drain with plenty of water. Owners see the code and steam cooking stops.

Common causes of E78 / F24

Drain sump level sensor pin dirty
Short circuit in the drain sump level sensor
Short circuit in the sensor module

✓ One safe check you can try

1. Let the oven cool fully. 2. Pour plenty of fresh water into the cavity drain area, as the guide describes, to flush it. 3. Wipe any visible residue from the cavity floor. 4. Turn the breaker off for one minute and restore power. 5. Call us if either E78 or F24 comes back. Do not open the casing or touch the sensor.

! Why to stop there

The sensor pin and module are inside the oven and are not owner repairs.
A short circuit needs electrical testing.
Residue may return if the drain path is partly clogged.

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

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 E26Wolf 24-inch E Series Code E26: Break or loose contact in climate sensor, or blocked duct

E78 / F24E78 / F24 questions

Which ovens show E78?

Only the plumbed CSOP2450TM and CSOP3050TM. Their drain sump has a level sensor, and the code points to that sensor or its module. On site we look at drain sump level sensor pin dirty and short circuit in the drain sump level sensor, then quote the repair in writing.

Will flushing the drain help?

Often, yes. A dirty sensor pin is the first thing to rule out, and a good flush with plenty of water can clear it. Starting point for us is usually drain sump level sensor pin dirty, with the price written down before any work.

What if it keeps coming back?

Then we check the sensor and module for a short circuit. We quote the price in writing before replacing anything. We would also rule out short circuit in the drain sump level sensor before recommending anything.