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 Volt Gas Valve is energized gas flows to Main Burner

Is flame sensed at the Main Burner?

(control system monitors the flame sensor)

YESNO

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

2.0 minimum AC amps

Water is heated to

set point

24 Volt Gas Valve de-energized

30second

Post-Purge cycle

Water heater goes into standby mode

24 Volt Gas Valve de-energized

30second

Inter-Purge cycle

Retries up to two more times

Control System

Locks Out

“Ignition Failure”

Fault Msg is

displayed

Figure 57

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Image 55
American Water Heater HCG3 130T 300 instruction manual Sequence Of Operation Flow Chart, YES no