Description of this flow chart can be found in the "SeqUenCe OF OPerATIOn" section found on page 26.
Switch power on to unit
Thermostat calls for heat
Blower power relay is energized to
start blower
Blower engages Prover Switch
24VAC power to the Igni on
Control and self check
Trial for igni on
Igni on Control provides power to Spark
Igniter and Pilot Gas Valve and monitors
Flame Sensor to determine if Burner is lit
Flame Proved?
Spark Off and Open main Gas Valve
Ignition Control monitors
flame signal
Loss of flame signal?
Thermostat is satisfied
Blower – off; Blower Prover – opens
Ignition Control – off; Gas Valve – closes
seQuenCe of operation flow Chart
NO
YES
YES
NO
figure 24.
26
Close pilot gas
5 minutes retry
valve and Spark off
Close Main valve
and Pilot valve
delay