Webasto Furnace: “F08”
warning RV furnace fault codes
What it means
Drive/combustion-air motor fault - the fan motor has an open circuit, short circuit, overload, or is mechanically blocked, so the heater cannot run its combustion and heating-air fan.
Most likely causes
- Fan wheel snagging, jammed, or blocked by debris common
- Short or open circuit in the drive motor or its wiring common
- Motor overload protection tripped less common
- Worn/failed combustion-air fan magnets or drive unit (EVO) less common
Safe checks you can do yourself
- With the heater off and cool, check that nothing obstructs the fan/air intake.
- Inspect the motor wiring and connector for damage.
How to reset / clear F08
- Remove any blockage or sluggishness in the fan.
- Switch the heater off and on; clear a lock-out with the fuse-pull reset if needed.
When to call a technician
If the fan spins freely and wiring is good but the fault stays, the drive unit (motor with combustion and heating-air fan) likely needs replacement by a technician.
Applies to
Air Top EVO 40 · Air Top EVO 40 B (petrol) · Air Top EVO 40 D (diesel) · Air Top EVO 55 · Air Top 2000 STC
FAQ
What does Webasto Furnace code "F08" mean?
Drive/combustion-air motor fault - the fan motor has an open circuit, short circuit, overload, or is mechanically blocked, so the heater cannot run its combustion and heating-air fan.
How do I reset Webasto Furnace F08?
Remove any blockage or sluggishness in the fan. Switch the heater off and on; clear a lock-out with the fuse-pull reset if needed.
What is the most common cause of F08 on a Webasto Furnace?
The most likely cause is fan wheel snagging, jammed, or blocked by debris.
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Sources
- Air Top Evo 40 / Air Top Evo 55 - Fault Codes / Troubleshooting (Fig. 503) — Section 5.4, Fault code F 08 (PC codes 09/89/15/95) (Butlertechnik / Webasto)
- Webasto Air Top 2000 STC Fault Error Codes — Section 5.5, F08 Combustion air fan short circuit / blocked (Butlertechnik / Webasto)
Note: On the 2000 STC, fan short circuit and fan blocked are both grouped under F08 (hex 09 short, 15 blocked, 89 interruption).
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.