Document Outline

• Table Of Contents
• Introduction
  • Qualifications
  • Service Warning
  • Service Reminder
  • Tools Required
• Installation Considerations
  • Instruction Manual
  • Closed Water Systems
  • Thermal Expansion
  • Air Requirements
  • Contaminated Air
  • Venting
    • General Venting Information
    • Maximum Equivalent Length Requirements
    • Intake Air Connection
  • Electrical Requirements
    • Grounding and Polarity
    • Power Supply Test
  • Installation Check List
• Features And Components
  • Front & Back Views
  • Top View
  • Combustion Blower & Burner Assembly
• Operation and Service
  • How It Works
  • Combustion Blower
  • Burner Assembly
  • Combustion Blower and Burner Removal
  • Flame Sensor
    • Flame Sensing Operation
    • Flame Sensing Current Test
  • Igniter
    • Igniter Current Test
  • Venturi
  • Gas Valve
    • Gas Valve Voltage Tests
    • Gas Valve Removal
  • Gas Pressure
    • Gas Pressure Test
    • Gas Flow Test
  • Pressure Switches
    • Construction & Operation
    • Control System Monitoring
  • Pressure Switch Tests
    • Continuity Test During Standby
    • Continuity Test During Operation
    • Pressure Test During Operation
  • Temperature Probe
    • Temperature Sensor Test
    • ECO Continuity Test
  • Control System Hardware
    • UIM (User Interface Module)
    • CCB (Central Control Board)
    • CCB Cover Removal And Replacement
    • CCB Circuit Board Layout
    • CCB Connection Identification
  • Wiring Diagram
• Control System Operation
  • Overview
    • Control System Features
    • Commercial And Residential Models
    • Control System Navigation
    • User Input Buttons
    • Desktop Screen
    • Status Icons
    • Operating States
  • Control System Menus
    • Temperatures
    • Heater Status
    • Display Settings
    • Heater Information
    • Current Fault
    • Fault History
    • Fault Occurrence
    • Restore Factory Defaults
    • Service Contact Information
  • Sequence Of Operation
  • Sequence Of Operation Flow Chart
• Troubleshooting
  • Rough Starting/Rough Operation
    • Not Enough Hot Water
    • Heater Status Menu
    • Things To Check Before Servicing
    • Resetting The Control System
  • Control System Unresponsive
    • UIM (LCD) Is Blank
    • UIM Is Inoperable
  • Fault Messages
    • AC Reversed
    • Temp Probe Open
    • Temp Probe Short
    • Flame Sensor Short
    • Flame Detect Error
    • Energy Cut Out (ECO)
    • Blocked Air Intake
    • Blocked Exhaust
    • Blower Prover Failure
    • Blower Prover Open
    • Low Igniter Current
    • Ignition Failure
    • Communication Failure