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Profire E/LNE Series Manual
1-9
Introduction
1.7.3 — Operation
Metered gas flows through the main gas shutoff cock, through the pressure regulator to the automatic gas valves and
butterfly valve to the gas manifold.
The butterfly gas valve modulates flow to burner input demand. The butterfly valve is positioned through mechanical
linkage by the modulating motor. The air control damper is positioned simultaneously by the modulating motor.
The automatic gas valve(s) cannot be energized unless the combustion air proving switch is closed. The low and high
gas pressure switches must be closed to prove proper gas pressure.
A normally open vent valve, if required, is located between the two automatic gas valves. This valve is shut when the
automatic gas valves are open. When the automatic valves are closed, the vent valve is open for venting gas to the
outside, should any be present.