SERVICE HANDBOOK

UIM (CONT)ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUALTable 5 - Operational States (Modes)STATEStandbyInput VerificationPre-PurgeIgniter WarmupIgnition ActivationIgnition VerificationInter-PurgeHeatingPost-PurgeFaultDESCRIPTIONThe water heater is not in an active heating cycle. This usually means the temperaturein the tank has reached Operating Set Point and has not dropped low enough to initiatea call for heat.The control system is waiting for specific conditions to occur (primarily pressure switchnormal state verification - see page 20) before the unit can continue in the Sequence ofOperation.The blower has been energized - the control system is purging out any excess gas orleft over products of combustion from the heat exchanger at the beginning of eachheating cycle.The igniter has been energized and is currently warming up to ensure proper ignition -typically last 17-20 seconds.The control system is allowing for a steady burner flame to be established. Duration ofthis and the Ignition Verification state is typically 4-6 seconds.Assurance of proper flame sense is being determined.After a failed trial for ignition the control system is purging out any excess gas or leftover products of combustion from the heat exchanger before another trail for ignition.Burner flame has been properly established - minimum flame sensing current hasbeen verified by the control system - water in the tank is being heated.The control system is purging out any excess gas or left over products of combustionfrom the heat exchanger after a successful heating cycle.The control system has detected a fault and declared a fault condition. The controlsystem is locked out. A fault message is displayed on the UIM (page 27). The problemthat caused the lock out must be corrected before the water heater can resume aheating cycle.Technical Literature Department 31 of 52 Ashland City, TN © 2008Servicing should only be performed by a Qualified Service Agent