750-297
Profire E/LNE Series Manual
4-7
Adjustments
actuators for fuel, air, and FGR (if so equipped) will be coordinated to provide optimum combustion throughout the
firing range.
4.9 — Firing Rate Controls
Firing rate adjustments are made at the modulating motor linkages to the combustion air inlet damper, air-oil metering
pump, and main gas butterfly valve. Settings are determined by the operating length of the levers and the angular
position on the shafts. Increasing the lever lengths on damper, pump or valve decreases the flow rate. Driving and
driven levers are approximately parallel, but the angles can be adjusted to vary the rate of change. The most rapid rod
travel occurs when the lever is perpendicular to the rod. The closer the rod comes to being parallel with the lever, the
slower the rod moves. ALWAYS allow the burner to return to low fire position before adjusting high or intermediate
settings. DO NOT alter low fire settings.
Normally, the air control damper will be approximately 1" open in low fire position. Excessive opening in low fire can
cause pilot ignition problems. Air to the pilot is supplied under pressure to compensate for variations in furnace
pressure, but the damper must be in low fire position for reliable ignition.
Keep fingers away from the air intake below the damper. The damper is actuated with sufficient force to cause severe injury.
!
Warning