Full sequence ignition device
25
10.4
Ignition and control sequence
lock memorised?
supply from the electronic control circuit
Air pressure switch at
rest?
NO
NO
starts fan
YES
Air pressure switch at
work?
NO
beginning of wait period
presence of flame?
NO
YES
YES
Air pressure switch at
work?
NO
YES
starts ignition discharges
opens gas valve
beginning of ignition period
flame presence?
end of ignition
period?
NO
NO
YES
closes gas valve
stops fan
interrupts ignition discharges
memorizes lock
turns on lock---out light
YES
reset push---button
pressed?
NO
YES
cancels lock
interrupts ignition discharges
gas valve open
flame presence?
Air pressure switch at
work?
NO
YES
YES
closes gas valve
NO
YES
Safety thermostat
opens the circuit?
NO
YES
Fig. 41