I-UDSA-UK (02-19) PN 06 00116 UDSA R3, page 15
Definitions
Start position:
The system is not in lock-out position and can proceed with the startup sequence upon a demand for heat.
Pre-purge time:
The 20-second period during which the combustion fan (venter) operates prior to activation of the ignition device.
Safety time:
The safety time is the 5-second delay between the gas valve being energized and the flame sensor checking for flame.
NOTE:
If no flame is sensed, the burner relay will
attempt ignition five times before going into lock-out mode.
Post-purge time: The 5-minute period between burner shut-down and the moment the combustion fan (venter) is de-energized.
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.
IGNITION SYSTEM
