FULTON FT-0080C, Installation, Operation, Maintenance And Parts Manual

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FT-C Vertical Electric Thermal Fluid Heater Manual 12 2013 ISSUE 1
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MODULATING BURNER
The function of the flame programmer must be greatly extended in a modulated system. Along with
limit controls, operating controls and interlock devices, the programmer automatically controls the
operation of the burner, blower motor, ignition, main fuel valves and modulating motor (or servo
motors).
The sequence of operation is as follows:
1) Beginning with power on, limit switch closed, fuel valves closed, and modulating limit
controller closed and calling for heat, the flame programmer begins its cycle and the blower motor
starts prepurge. The modulating circuit closes, driving the air dampers to maximum for prepurge.
2) The air flow proving switch must be closed now. After timed prepurge, the modulating motor
(servo motor) drives the air damper to its low fire position. All start interlocks must be proven or the
flame programmer will lockout.
3) (Units with Gas Pilot) Ignition and pilot are energised and a timed trial for pilot ignition begins.
After the pilot flame is proven, ignition turns off and the main fuel valve is energised. Pilot fuel is
turned off and the modulating motor
4) (Units with Spark Ignition) The spark and oil valves are energised and a timed trial for ignition
begins. With the flame proven, the control advances through its main light off sequence, and the
ignition shuts off. At this time, with the flame proven, the modulating motor (servo motor) is
released to automatic.
5) When the modulating motor (servo motor) is released to automatic, it receives its signal from
the modulating temperature controller. The modulating motor (servo motor) then drives the
modulating fuel valve and air damper in proportion to the heat demand.
6) During the initial call for heat, the modulating fuel valve and air damper will drive to their
full-fire position. As the temperature set point is approached, the modulating motor (servo motor)
will continue to reduce the input until low-fire position is reached. Input automatically increases and
decreases according to load demand.
7) When the fluid temperature reaches the set point of the temperature controller or of the optional
operating limit controller, all fuel valves will close and the flame programmer will advance to the
post purge cycle. When the postpurge cycle begins, the modulating motor will be in the low fire
position. At the end of postpurge, the burner motor stops and the entire system is ready for restart
on demand.