6
Figure 3: Sequence of Operation
Thermostat Calls
for Heat
Circulator Output
Energized
Prepurge (30 seconds)
Ignition Source Energized
Pilot Gas On
Blower Starts
Trial For Ignition
Ignition Source Off
Main Gas On
Call For Heat Ends
Standby
Intelligent Hydronic
Control can display
(typical)
Delay 60 Seconds
Ignition Source Off
Pilot Gas Off
Main Gas Off
Blower Off
Circulator Output De-Energized
Standby
Continuous
Retry
Self Testing
Waiting for Pressure
Switch to Open
Waiting for Limit to Close
Waiting for Pressure
Switch to Close
Pilot Flame
Proven
Pilot Flame
Not
Proven
