Slant/Fin Error Lockout 109 / Hold 110: Ignition failure — failed to prove flame after 3 attempts
The control attempted ignition three times and never proved a stable flame, so it locked out (Lockout 109; Hold 110 = ignition failure occurred during a recycle-and-hold). The Slant/Fin CHS manual lists these documented causes: a disconnected high-voltage spark cable, a disconnected flame-rod signal wire, blocked venting (exhaust-vent, air-inlet, combustion blower, gas-valve venturi, or heat exchanger), insufficient gas line pressure (manual gas valve closed or low supply pressure), no 120VAC to the spark generator, a faulty spark generator, no 24VAC to the gas valve, or a faulty gas valve. (The manual does not specify an electrode gap dimension.) We diagnose and repair it across Greater Vancouver — same-day and after-hours.
The control attempted ignition three times and never proved a stable flame, so it locked out (Lockout 109; Hold 110 = ignition failure occurred during a recycle-and-hold). The Slant/Fin CHS manual lists these documented causes: a disconnected high-voltage spark cable, a disconnected flame-rod signal wire, blocked venting (exhaust-vent, air-inlet, combustion blower, gas-valve venturi, or heat exchanger), insufficient gas line pressure (manual gas valve closed or low supply pressure), no 120VAC to the spark generator, a faulty spark generator, no 24VAC to the gas valve, or a faulty gas valve. (The manual does not specify an electrode gap dimension.)
Slant/Fin fault codes can vary by model and series. Use this as a guide — the same code can have more than one cause. Our Technical Safety BC–licensed technicians read the code, confirm it against your unit's manual, and diagnose the true cause before any repair.
Likely causes of Slant/Fin error Lockout 109 / Hold 110
- Incorrect spark igniter electrode gap or faulty/dirty igniter
- Disconnected spark cable or igniter ground wire
- Insufficient gas supply (manual gas valve closed or low gas pressure)
- Blocked exhaust vent, air intake, blower, gas-valve venturi, or heat exchanger
- Disconnected flame rod, faulty gas valve, or no spark from the spark generator
What you can safely check
- Confirm the manual gas shutoff valve to the boiler is fully open and other gas appliances work
- Check that the outside exhaust and intake vent terminals are not blocked
Beyond these checks, do not open the unit or touch gas/electrical parts — BC law requires a licensed gas fitter. Call us for a proper diagnosis.
Error Lockout 109 / Hold 110 usually leaves you without heat or hot water and can indicate a safety-related fault. Don't keep resetting it — call for priority after-hours Slant/Fin repair.
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Parts often behind Slant/Fin error Lockout 109 / Hold 110
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Slant/Fin Error Lockout 109 / Hold 110 Repair Across Metro Vancouver
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