10
3.
The prepurge is initiated when the high fire interlock (purge air flow interlock) is closed within
180 seconds, confirming that the firing rate motor reached its high fire position. The supervised
prepurge time is 30 seconds.
*
4.
When the prepurge is completed, the firing rate motor is driven towards the low-fire position, to
be reached within 180 seconds.
5.
The burner is ready for ignition if the following conditions are met:
– Recycling and non recycling interlocks closed.
– Low-fire switch (minimum air flow switch) closed.
6.
The spark ignition and the pilot valve are energized.
7.
The ignition transformer is de-energized after 5 seconds pilot trial for ignition time
8.
As soon as flame is detected, the ED510 message center will provide a readout of the signal
strength both during pilot proving time and main burner operation.
9.
Following a 10 second proved pilot stabilization period, the main fuel valve (terminal 7) is ener-
gized.
10. After the main burner trial for ignition time (3 seconds for gas, 5 seconds for oil), the pilot valve
is de-energized and the firing rate motor is released to automatic control.
11. The supervised start-up program has ended and the burner is in operation.
NORMAL BURNER SHUTDOWN
— When the operating control (recycling interlock) opens, the main fuel valve is de-energized
and the firing rate motor is driven to the low position.
— Following a 10 second post-purge the blower motor is de-energized.
*
Dipswitches #3, #4, and #5 extend the purge timing from 1 second up to 15 minutes. See “Dipswitches for Selectable
Operation.”
FLAME SIGNAL
COMMENT
0 — 9
Not acceptable
10
Minimum required
20 or more
Normal
