TL;DR
A flare pilot out means the primary flare ignition is lost. Check the ignition gas supply, pilot thermocouple, and ignitor before dispatching to the flare tip.
What you might see
- pilot flame out alarm active
- pilot thermocouple reading ambient temperature
- flare tip not visible on camera
- automatic ignition retrying without success
Likely causes
Ignition gas supply pressure too low or ignition gas supply valve closed
Pilot thermocouple failed or connection corroded giving a false pilot-out signal
Ignitor spark plug fouled or electrode gap incorrect
Wind speed exceeding the pilot design flame stability limit
Required tools
- Gas detector (calibrated for H2S and hydrocarbons)
- Multimeter (for thermocouple millivolt check)
- Pilot gas supply pressure gauge
- Fall protection equipment (for elevated access)
Safety first
- Flare systems are processing hazardous hydrocarbon or sour gas. Approach only with calibrated gas detection. H2S above 10 ppm requires supplied-air equipment.
- Hot work permit is required for any work at the flare tip or on the flare stack structure.
- During a pilot out condition, unlit gas may be exiting the flare tip. Do not approach the flare tip directly until the pilot is re-established and the flare confirmed lit.
Procedure
- 1
Check the pilot gas supply pressure at the ignition gas panel. Confirm the supply valve is open.[1]
- 2
Check the pilot thermocouple output at the field junction box. A reading near 0 mV confirms the thermocouple is open circuit or at ambient.[1]
- 3
Attempt a manual pilot relight from the ignition control panel. Observe whether the ignitor spark can be heard or seen.
Warning: Flare systems handle hazardous hydrocarbon gas. Approach the flare drum and knock-out drum area only with a gas detector. H2S may be present if the feed includes sour gas. - 4
Check the wind speed reading on the local anemometer. If wind speed is above the pilot stability limit, wait for wind conditions to improve before attempting relight.
- 5
If the ignitor fires but the pilot does not light, increase the pilot gas flow rate slightly above the minimum ignition flow.
Warning: Do not increase pilot gas flow excessively. Over-fuel prior to ignition can cause a puff ignition event. - 6
If the thermocouple is suspect, replace it at the next available access opportunity. Thermocouple replacement at an elevated flare tip requires hot work permit and fall protection.
- 7
Log all pilot out events with time, wind conditions, and restoration method for the flare performance record.
Sources
John Zink Hamworthy (Koch) John Zink ZTOF / EEF Flare System general technical documentation, John Zink Hamworthy (Koch)
John Zink ZTOF / EEF flare system general pilot ignition and thermocouple maintenance procedures (general)
More guides for John Zink Hamworthy (Koch) John Zink ZTOF / EEF
How to diagnose flare tip burnback on a John Zink ZTOF / EEF flare system
Flare tip burnback means combustion is inside the tip body. Verify purge gas flow and steam injection immediately. Activate the site emergency response plan.
How to respond to a knockout drum high level alarm on a John Zink ZTOF / EEF flare system
High knockout drum level means liquids may carry over to the flare tip. Drain the drum immediately and identify the source of elevated liquid flow.
Stop fixing the same fault twice.
Dovient turns guides like this into your team's shared playbook, with AI that catches recurring issues before they break the line.