1611UDSBD-3GBEN, Pag. 23/36
Defi nitions
Start position:
The system is not in lock-out position and can proceed with the start-up sequence upon a demand for heat.
Pre-purge time:
This is a period of 20 seconds during which the combustion fan (venter) operates prior to activation of the ignition device.
Safety time:
The safety time is the delay between the gas valve being energised and the fl ame sensor checking for the presence of a
fl ame. This is a period of 5 seconds.
Note:
If
no
fl ame is sensed, the burner relay will
attempt ignition 5 times before going into lock-out mode.
Post-purge time:
This is the time of 300 seconds between burner shut-down and the moment the combustion fan (venter) is de-energized.
Normal
Heat Cycle
Operating
Sequence
Ignition
system
This heater is equipped with a direct spark integrated control relay. The control
relay monitors the safety devices and controls the operation of the venter motor
and the gas valve between heat cycles.
The time line below illustrates a normal heat cycle.
Figure 10
