Dacor Range F9 Error: Oven thermal runaway
This dacor range f9 error code guide explains what this fault means for your Dacor appliance and how to respond safely. What F9 Means on a Dacor Range F9 is a thermal runaway fault — the oven cavity exceeded its maximum safe temperature during normal bake or broil operation. The control board performs an emergency […]
~10%
DIY Fixable
From $300
Typical Repair Cost
60-120 min
Pro Repair Time
Quick Assessment
Answer to continue safely
Is it safe to keep using?
No. Thermal runaway means uncontrolled heating. This is a fire hazard. Do not use the oven cavity.
Can I reset the code?
Yes. A breaker reset may clear F9 temporarily, but the stuck relay or shorted element must be replaced.
When to stop immediately?
Stop if you notice: Do not restart the oven under any circumstances until the cause of thermal runaway is confirmed and repaired — this is a fire safety issue., Do not use the surface burners on an all-gas range if you smell gas residue from the oven area..
Symptoms You May Notice
Strong burning smell during normal baking
A pronounced burning or scorching smell comes from the oven during a standard bake or roast cycle at normal temperature settings — well before the oven should reach any dangerous temperature.
Range shuts off mid-cycle displaying F9
The oven cuts out completely during cooking, all heating stops, and F9 flashes on the control display with an audible alarm.
Oven door and control panel are unusually hot
The door glass and the front control panel area are much hotter than normal for the selected temperature setting, indicating the cavity exceeded its set point by a large margin.
Food is charred or scorched at moderate temperature settings
Results from the oven are consistently and severely overcooked — food is burnt at temperatures where it should be only lightly browned.
Possible Causes
Bake gas safety valve stuck open
The oven gas safety valve is not closing when the control board cycles it off, allowing gas to flow continuously to the bake burner. This produces runaway heating and is the most dangerous cause of F9 on Dacor gas and dual-fuel ranges.
Requires ProfessionalRTD sensor reporting falsely low temperature
A failing RTD probe reads a temperature well below actual, causing the board to keep the burner running far longer than required. The oven overheats while the board believes it is still below the set point.
DIY PossibleControl board relay stuck closed
On dual-fuel Heritage (HGOR) and Modernist (DOP) ranges, a relay on the EOC board can stick closed, keeping the bake element energized even when the control commands it off.
Requires ProfessionalSafe Checks You Can Do
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1
Shut off the gas supply immediately
If F9 appeared during active cooking and you smell burning, turn off the gas supply valve behind the range without delay. Do not restart the oven. Open windows to ventilate the kitchen.
The gas shutoff valve is typically behind or below the range — a quarter-turn lever or knob perpendicular to the pipe means off.
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2
Test the RTD sensor after the oven cools
Once the range is completely cool (allow 2 hours), unplug the range and test the RTD probe resistance. A healthy probe reads approximately 1080 ohms at room temperature. A reading significantly below 800 ohms points to a drifting sensor that caused false-low readings and runaway heating.
A sensor that passes the room-temperature test but still caused F9 may be drifting at high temperature — report both facts to your technician.
Tools required
When to Call a Professional
Contact a qualified technician if:
- Gas safety valve is suspected — valve replacement requires gas-line disconnection inside the range chassis, which must be performed by a licensed technician.
- RTD sensor tests normal but F9 recurred — stuck relay on the control board requires board diagnosis and replacement.
- Any oven that experienced thermal runaway should be fully inspected before use — internal wiring insulation may have been damaged.
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