SERVICE HANDBOOK

ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUALCONTROL SYSTEMINTRODUCTIONThis portion of the service manual will cover the control system. The control system includesseveral components: a UIM (User Interface Module), a CCB (Central Control Board), and anOverlay/Button Pad. More information on these components will be given in the pages thatfollow.Control System FeaturesAdvanced Diagnostics: Plain english text based diagnostic information (fault messages)on board to help equipment owners accurately describe the reason for a given lock outcondition and service technicians quickly and accurately service the water heater.Fault History Screen: Will retain a 9 event history of fault messages with a time stamp.This will help diagnose load and/or environmental conditions that may be contributing to aproblem with operation or a lock-out.Fault Occurrence Screen: Will keep a running total of how many times each lock out/faultcondition has occurred since the water heater was first installed. This is valuable informationfor a service technician when trying to determine root causes for service problems.Help Screens: Text based operational information to help the user understand how tochange settings, navigate the menu screens and what the various icons and displayed itemsmean.EMI / RFI Filtering: Built into all control system circuit boards. (EMI = Electro MagneticInterference, RFI = Radio Frequency Interference) Helps prevent or eliminate erraticoperation caused by EMI/RFI.Technical Literature Department 26 of 52 Ashland City, TN © 2008Servicing should only be performed by a Qualified Service Agent