750-297
Profire E/LNE Series Manual
1-3
Introduction
1.3.3 — Firing Rate Controls
Regardless of the fuel used, burner input is fully modulated between low fire and high fire on boiler demand. The firing
rate is controlled by the potentiometer-regulated modulating motor. The combustion air control damper, oil metering
pump, and/or gas volume butterfly valve are controlled through variable rate rod and lever linkages. The modulating
motor rotates 90º from low to high position. Flow rate through each component is adjusted by positioning the control
rods on the levers and the angular position of levers on shafts. The lever on the modulating motor shafts actuate the
high fire position proving switch.
1.4 — Combustion Air Handling System
The combustion air handling system consists of two major components:
1.5 — Firing Head
Access to the firing head is provided by
swinging open the impeller housing.
First, disconnect the damper linkage,
release the housing latch, and swing the
housing to the open position. An
internal gas pilot is standard on all
burners. Pilot gas pressure is adjusted at
the pilot pressure regulator.
FIGURE 1-1.
Burner Housing
Component
Details
Damper Assembly
A rotary damper regulates the combustion air volume and is positioned by a
modulating motor. The damper is normally almost closed in the low fire position
and opens as the burner drives toward a high fire position.
Motor Driven Impeller
The diameter of the impeller determines available air pressure and the width
determines air capacity in cubic feet per minute. Alternate motor-impeller
combinations are available for 50 cycle or 60 cycle power and for firing against
either moderate or high furnace pressure. All standard impellers are sized for up
to 2,000 ft. altitudes and up to 4” W.C. furnace pressures. Alternate impeller
wheels are available. For higher altitudes and higher furnace pressures, motor
and impeller combinations are determined at the factory.
GAS PILOT ASSEMBLY
WITH ELECTRIC SPARK IGNITION
AIR ATOMIZING OIL NOZZLE ASSEMBLY
(SINGLE OR DUAL)
FLAME SCANNER
AIR DIFFUSER
GAS SPUDS
GAS PILOT LINE
ATOMIZING AIR LINE
ELECTRODE LEAD
FUEL OIL LINE
BURNER HOUSING
GAS INLET
