Lennox BAC 030 SNM 3M Installation, Operating And Maintenance Manual page 56

GAS BURNERS
Gas burner fi re-up sequence
Ionisation 1 second after the end of sparking?
NO
Signal from ionisation probe still ON?
NO
• 52 •
Operation from control
Thermostat GAS =Closed
Supply thermostat limit?
(Auto Reset)
YES
Gas low pressure switch?
YES
Gas ignition control block signal
Extraction fan ON
AIR pressure switch ON
backfi re thermostat ON?
YES
Pre-ventilation 30 seconds
Fire-up eectrode 4s
Gas valve open
YES
Gas valve remains open
Normal operation
Air press switch ON
or backfi re thermostat?
YES
NO
NO
NO
Gas control valve closes
Gas control valve closes
BURNER STOPS
NO
Fault on gas control
block
6 minutes delay
Fault on CLIMATIC™
YES
BALTIC-IOM-0412-E / Service manual
BURNER STOPS