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W415-1007 / A / 07.18.12
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Apply Power To Furnace
Thermostat Calls For Heat
Air Proving Switches
Proved Open & Limit
Circuit Closed
Wait For Air Proving Switch
to Open. Flash "3"
Wait For Limit Circuit
to Close and/or Reset
of Flame Rollout.
Flash "1"
Combustion Air Blower On
Air Proving Switch Proved
Closed Within 60 Seconds?
Combustion Air Blower Off
Flash "2"
60 Minute Wait Period
Prepurge 15 Seconds
HSI Energized 5 Seconds
(10 Seconds on Retries)
Main Valve Opens
HSI De-Energized
Main Burner Lights And Is Sensed
During Trial For Ignition?
Main Valve Closes
Failed Trials For Ignition
Less Than Four During
This Ignition Sequence?
Heat Circulating Air Fan On
After Programmed Delay
Flame Sense Lost?
Thermostat Call For Heat Ends
Main Valve Closes
Combustion Air Blower Off After Post
Purge (5 Seconds)
Circulating Air Fan Off After
Blower Off
Delay
Wait For Next Call For Heat
Main Valve Closes
Flame Sence Lost More Than Four
Times In This Call For Heat?
Combustion Air Blower
Off After Post Purge
Circulating Air Fan Off
After
Blower Off
Delay
1 Hour Lockout Reset
Delay. Flash "4"
30 Seconds Between
Trial Purge
NO
NO
YES
YES
YES
NO
YES
NO
YES
SEqUENCE OF OPERATION
Troubleshooting Flowchart
19.3 TRoUbleshooTInG floWChaRT