State Industries SUF-130- 300/400/500 Sequence Of Operation Flow Chart, Pre-Purge cycle

Sequence Of Operation Flow Chart

If tank temperature drops below Operating Set Point minus

Differential setting a heating cycle is activated

	Control System performs diagnostic checks				Control System Locks Out
Normal State of all pressure switches and ECO are checked
				NO
	Blower Prover pressure switch verified open				Displays Fault Msg
All other pressure switches and ECO are verified closed
		Combustion Blower is energized
		Pre-Purge cycle
					Control System Locks Out
		Blower Prover switch contacts confirmed
			NO		“Blower Prover Open”
		closed by control system
					Fault Msg is displayed
		Igniter is energized for warm up period

Does Control System sense minimum
	NO
Igniter amps?

24 VAC Gas Valve is energized

gas flows to Main Burner

Is flame sensed at the Main Burner?

(control system monitors the flame sensor)

YESNO

Water is heated to	24 VAC Gas Valve
set point	de-energized

Control System Locks Out “Low Igniter Current” Fault Msg is displayed

2.0 minimum AC amps

300,000 & 400,000 Btu/hr Models

3.1 minimum AC amps

500,000 Btu/hr Models

24 VAC Gas Valve de-energized

30second

Post-Purge cycle

Water heater goes into standby mode

30second

Inter-Purge cycle

Retries up to two more times

Control System

Locks Out

“Ignition Failure”

Fault Msg is

displayed

Figure 58

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