55
Servicing should only be performed by a Qualified Service Agent
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 system check
Normal State of all pressure switches and ECO are checked
Blower Prover pressure is switch verified open
All other pressure switches and ECO are verified closed
Blower Prover switch contacts confirmed
closed by Control System
Igniter is energized for warm up period
YES
24 Volt Gas Valve is energized
gas flows to Burner
Does Control System sense minimum flame sensing
of 1.0 µA (DC micro amps) through Flame Sensor?
Control System Locks Out
Displays Fault Msg
Combustion Blower is energized
Pre-Purge cycle
YES
Does Control System sense minimum
0.5 AC amps through the Igniter?
YES
Control System Locks Out
“Blower Prover Open”
Fault Msg is displayed
NO
Control System Locks Out
“Low Igniter Current”
Fault Msg is displayed
NO
YES
NO
Water is heated to
set point
24 Volt Gas Valve
de-energized
30 second
Inter-Purge cycle
24 Volt Gas Valve
de-energized
Retries up to
two more times
30 second
Post-Purge cycle
Control System Locks Out
“Ignition Failure”
Fault Msg is displayed
Control System goes
into Standby mode
NO
