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ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUAL
Technical Literature Department 40 of 52 Ashland City, TN © 2008
Servicing should only be performed by a Qualified Service Agent
SEQUENCE OF OPERATION
Call for heat initiated
Air Pressure Switch Test Is Performed
Blower Prover Switch is verified open
Blocked Intake and Blocked Exhaust Switches are verified closed
Blower Prover Switch is verified closed
Igniter is energized for warm up period
(approx 17 seconds)
YES
Gas Valve Is Energized
Gas Flows To Burner
Control System (CCB) Verifies Flame
Sensing Current at 1.0µA DC Micro Amps Minimum
Control System Declares
Fault Condition - Locks Out
One of the following
Fault Messages Displayed:
“Blower Prover Failure”
“Blocked Inlet”
“Blocked Exhaust Vent”
NO
Blower Motor is energized
Pre-purge State
YES
Control System (CCB) Verifies Igniter
Current at 2.0 AC Amps Minimum
YES
Control System Declares
Fault Condition - Locks Out
“Blower Prover Open”
Fault Message Displayed
NO
Control System Declares
Fault Condition - Locks Out
“Low Igniter Current”
Fault Message Displayed
NO
YES NO
Water Is Heated To
Operating Set Point
Gas Valve Is
De-energized
Inter-Purge State
30 Sec Approx
Gas Valve Is
De-energized
Retries Up To
3 Times
Post-Purge State
30 Sec Approx
Control System Declares
Fault Condition - Locks Out
“Ignition Failure”
Fault Message Displayed
Control System Goes Into
Standby State/Mode