A typical train runs from a manual shutoff and sediment trap through the pressure regulator, a low gas pressure switch, two automatic safety shutoff valves in series, a high gas pressure switch and the firing rate valve, with leak test cocks between the safety valves. Larger burners add proof-of-closure switches and valve leak proving. The layout and components are set by code and insurer requirements by burner size.
Gas train's leak test cocks showed the first safety valve passing, it's getting replaced before we fire again.
Also heard as
- fuel train
- gas valve train
Related terms
Dirt leg
A capped vertical stub of pipe below the gas inlet tee that traps scale, dirt and liquid before they reach the gas valve.
BMS
Burner management system: the safety controls that handle purge, ignition, flame proving and trips on larger boilers.
Nuisance trip
A safety shutdown or lockout caused by a faulty or marginal device, not by a real unsafe condition.
Burner
The assembly that mixes fuel with air and holds a stable flame to heat the boiler.