Burner fail to start (no ignition) · Crossdraft
Burner fail to start (no ignition) on Crossdraft booths
If your crossdraft booth's HMI is showing a burner fail-to-start fault, typically with codes referencing ignition module timeout, flame sensor failure, or gas valve actuation, the diagnosis path is mechanical, not filtration. Crossdraft booths run horizontal airflow front-to-rear, and the AMU is most often mounted at the front of the booth integrated with the intake-door filter wall. The burner sits in that AMU package; when it fails to start, the whole supply side is offline regardless of filter state. Replacing intake or exhaust media won't fix this. The reason this page exists is so a filter search that landed here doesn't lead to a wasted kit purchase.
Quick answer
A burner fail-to-start fault on a crossdraft booth is a mechanical issue with the AMU (air make-up unit) burner package, typically Honeywell controls on older installations and a mix of Honeywell and Siemens on later ones. This is a professional service issue, not a filter issue. Filter cycle is unrelated to ignition fault. The diagnostic flow involves gas pressure verification, ignition module check, flame sensor cleaning, and burner control reset, in that order. Operator-level checks are limited to confirming gas supply is on and looking for visible faults at the AMU control panel.
Diagnostic logic for Burner fail to start (no ignition) on Crossdraft
The honest answer: filters are not the cause and filters are not the fix. Crossdraft AMU burners fail to start independent of intake-door filter or exhaust filter loading. Fresh media won't restart a burner; loaded media won't prevent one from starting except in one edge case below.
Where filter state can mask burner symptoms. A small subset of crossdraft AMU control packages interlock burner ignition against an AMU airflow proving switch. If your AMU pre-filter (sitting upstream of the burner inside the AMU enclosure) is severely overdue and airflow has dropped past the proving threshold, the burner won't ignite and the HMI will report a burner fault, when the actual root cause is filter restriction. Replacing the AMU pre-filter is worth checking before booking service IF you've been past the 90-day cycle. In every other case, the burner fault is a control or combustion issue.
The 25-entry filter media taxonomy on this site is for filter selection across intake-door panels, exhaust-pit pads, and arrestor sets, not for burner diagnosis. If you arrived here from a filter search by mistake, the filter-side symptom hub is the right entry point.
Regulatory landscape
A crossdraft running with a faulted burner is operating outside design conditions, supply air isn't conditioned to the spec required for the paint product's cure window, which directly affects finish quality and operator exposure. OSHA 29 CFR 1910.107 requires booth operation per manufacturer specs. Don't operate the booth for spray work until the burner fault is cleared by qualified service.
Burner fail to start (no ignition) on Crossdraft FAQs
Can I diagnose burner fail-to-start myself on a crossdraft?
Operator-level checks: confirm gas supply is on at the building shutoff, read the HMI fault code, and visually inspect the front AMU enclosure for any obvious damage or unusual sound. Anything beyond that is professional service — gas, ignition, and high-voltage controls aren't operator-scope work.
Will replacing my intake-door or exhaust filter kit fix this?
No. Intake-door and exhaust filters have no relationship to AMU burner ignition. The only filter-side variable is the AMU pre-filter inside the AMU enclosure, and only in the edge case where it's tripping an airflow proving switch.
My crossdraft was running fine yesterday and now the burner won't start. What changed?
Most common: a transient gas supply event (utility work, regulator drift), an ignition module that's been failing intermittently for weeks and finally crossed threshold, or a flame sensor that finally accumulated enough carbon to fail. Service identifies which.
My crossdraft is older and uses Honeywell controls — is that a known weak point?
Honeywell S87 and RM7800-series modules are workhorses but they age out. On a 15-plus-year-old crossdraft, the ignition module is a common service replacement and not a sign of broader issues. Plan for module replacement as routine wear rather than treating it as exceptional.
My HMI says the booth fan is running but the burner won't start. Is the booth safe to use?
The exhaust fan can run independent of the burner; the booth will move air but supply isn't conditioned. For prep, sanding, and cleanup that's acceptable. For spray work where ambient air is out of spec for the paint product, do not operate. Check your paint manufacturer's temperature window.
Should I subscribe to AMU pre-filter on a faster cycle to prevent future burner faults?
Only if AMU pre-filter restriction has been identified as your specific root cause. Otherwise faster pre-filter cycle won't prevent ignition module, flame sensor, or gas-supply faults — which account for the vast majority of crossdraft burner service calls.
Sources
Primary references cited on this page.
- OSHA 29 CFR 1910.107 — Spray Finishinghttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.107
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