Lennox FCM 85 Installation, Operating And Maintenance page 72

HEATING : GAS BURNER
GAS BURNER FIRE-UP SEQUENCE
Operation from control thermostat GAZ
NO
NO
FLEXYII_WSHP-IOM-0909-E
=Closed
Supply Thermostat Limit?
(Auto Reset)
YES
Gas Low Pressure switch?
YES
Gas Ignition Control Block Signal
Extraction Fan ON
AIR Pressure Switch ON
Backfire Thermostat ON?
YES
Pre-Ventilation 30 seconds
Fire-up Electrode 4s
Gas Valve Open
Ionisation 1second after
the end of sparking?
YES
Gas Valve remains Open
Normal Operation
Air Press Switch ON or
Backfire Thermostat?
YES
Signal from Ionisation
probe still ON?
NO
NO
NO
Gas Control Valve
Closes
NO
BURNER STOPS
Fault on Gas
Control Block
6 Minutes Delay
Fault on CLIMATIC
YES
Gas Control
Valve Closes
BURNER
STOPS
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