By burner control
By symptom
Why a burner control declares flame failure, how the stage of the trip narrows the cause, and the evidence that separates fuel, air, ignition and flame-detection problems.
SymptomBoiler burner lockout during ignitionA burner that locks out during the ignition trial usually has an ignition, pilot fuel, air or flame-detection problem. How to tell which, and what evidence to collect.
Overview
Packaged steam and hot-water boilers share the same building blocks: a burner and its flame safeguard control, a fuel train, combustion-air fan, feedwater and level controls. Most stoppages show up first as a lockout or alarm on the burner control.
Common problems
Flame failure and ignition lockouts
The flame safeguard did not prove a stable flame during pilot or main-flame trial. Typical areas to check are fuel supply pressure, the ignition transformer and electrode, the flame scanner and its signal, and combustion air.
Low-water and level trips
The low-water cutoff or level control shut the burner down. Look at feedwater pump operation, level-column blowdown practice, and whether the trip followed a sudden steam demand.
High steam pressure or limit trips
An operating or high-limit pressure control opened. Compare the setpoints with the load profile, and check whether the firing-rate control is following demand.
Combustion-air and draft faults
Air-flow or draft proving switches did not make, or opened during firing. Fan condition, damper position, linkage and stack draft are the usual suspects.
Evidence that helps
- Photo of the burner control or HMI alarm screen
- Controller make and model from the nameplate
- Steam pressure, firing rate and fuel pressure trends
- Alarm history around the trip