dunphy TD - Page 54

Operating Instructions For TD/TAD4 Dual Fuel Burner
June 13 54 of 165 TD/TAD4 Manual Rev 4
State
no.
State name
Description
8.
Pre-purge
Once the servo motors are at their purge positions the controller
starts the pre-purge (t2) timer.
9.
Move to ignition
positions
When t2 has elapsed, the fuel and the air motors are moved to
the ignition position for the selected profile. The controller will
wait at the ignition positions while the gas valve proving
sequence finishes before progressing to stage 10
10.
Pre-ignition
Once the fuel and air motors are at their ignition positions, the
ignition transformer output is energized and pre-ignition time
(t3) is starts.
11.
Pilot ignition
Once t3 has elapsed the ignition transformer remains on, first
main valve if required for pilot flame gas, and pilot valve
outputs are energised and the first safety time (t4) is started.
If firing on oil and ignition selected to be with both pilot and
main valve, use timing in the start-up sequence table for main
valve 1.
If firing on oil and ignition with main valve is not selected the
pilot ignition will occur with only the pilot valve, use timing in
the start-up sequence table for main valve 2.
12.
Pilot ignition
interval
When t4 is complete, a flame must be detected or the controller
will lockout the burner and move to stage 0. The ignition
transformer may optionally be on or off (See option parameter
14.6).
13.
Main ignition
Once the pilot interval time (t5) has elapsed, the second (and
first if not already open) main valve output(s) for gas, or main
oil valve output for oil is energized and the second safety time
(t6) is started.
If firing on oil and ignition with main valve was selected the
main oil valve will have already opened for pilot ignition. The
ignition transformer may optionally be on or off (See option
parameter 14.6). A flame and air pressure signal must be
detected or the controller will lockout the burner and move to
stage 0.
14.
Wait for Main
flame established
When t6 has expired, the pilot valve output is turned off. If
permanent pilot is selected and the burner is firing on gas, then
the pilot will remain open with the main valves.
Main flame interval time (t7) is started. A flame and air pressure
signal must be detected or the controller will lockout the burner
and move to stage 0.
15.
Moving to low
fire
When t7 has elapsed, the flame is considered established and the
fuel and air motors are moved from their ignition positions to
their low fire positions and held at those positions for the
duration of the Low Fire Hold Time (t8). A flame and air
pressure signal must be detected or the controller will lockout
the burner and move to stage 0.