Figure 3: Sequence of Operation
Thermostat Calls
for Heat
Circulator Output
Energizes
Waiting For
Damper to Open
Ignition Source Energized
Pilot Gas On
Limits Closed Checked
Trial For Ignition
Ignition Source Off
Main Gas On
Pilot Flame
Proven
Pilot Flame
Not
Proven
Call For Heat Ends
Standby
IQ Boiler Control
can display
(typical)
Delay 60 Seconds
Ignition Source Off
Pilot Gas Off
Main Gas Off
Vent Damper De-Energized
Circulator Output De-Energized
Continuous
Retry
Standby
Self Testing
Vent Damper Energized
Waiting For
Damper To Close
