1
table of Contents
TABlE Of CONTENTS .......................................................................... 1
INTRODUCTION .................................................................................... 2
Qualifications
..................................................................................... 2
Service Warning ................................................................................ 2
Service Reminder .............................................................................. 2
Tools Required ................................................................................... 2
INSTAllATION CONSIDERATIONS ..................................................... 3
Instruction Manual ............................................................................. 3
Closed Water Systems ...................................................................... 3
Thermal Expansion ............................................................................ 3
Air Requirements ............................................................................... 3
Contaminated Air ............................................................................... 3
Venting ............................................................................................... 4
General Venting Information ....................................................... 4
Maximum Equivalent length Requirements ............................... 4
Intake Air Connection .................................................................. 5
Electrical Requirements ..................................................................... 6
Grounding and Polarity ............................................................... 6
Power Supply Test ...................................................................... 6
Installation Check list ........................................................................ 7
fEATURES AND COMPONENTS ......................................................... 8
front & Back Views ........................................................................... 8
Top View ............................................................................................ 9
Combustion Blower & Burner Assembly ............................................ 9
OPERATION AND SERVICE ............................................................... 10
How It Works ................................................................................... 10
Combustion Blower ..........................................................................11
Burner Assembly ............................................................................. 12
Combustion Blower and Burner Removal ....................................... 14
flame Sensor .................................................................................. 18
flame Sensing Operation ......................................................... 18
flame Sensing Current Test ...................................................... 19
Igniter ............................................................................................... 20
Igniter Current Test .................................................................... 20
Venturi ............................................................................................. 22
Gas Valve ........................................................................................ 23
Gas Valve Voltage Tests............................................................ 23
Gas Valve Removal ................................................................... 24
Gas Pressure ................................................................................... 25
Gas Pressure Test ..................................................................... 26
Gas flow Test ........................................................................... 27
Pressure Switches ........................................................................... 28
Construction & Operation .......................................................... 28
Control System Monitoring ........................................................ 29
Pressure Switch Tests ..................................................................... 31
Continuity Test During Standby ................................................. 31
Continuity Test During Operation .............................................. 32
Pressure Test During Operation ................................................ 32
Temperature Probe .......................................................................... 35
Temperature Sensor Test .......................................................... 35
ECO Continuity Test .................................................................. 36
Control System Hardware ......................................................... 37
UIM (User Interface Module) ............................................... 37
CCB (Central Control Board) .............................................. 39
CCB Cover Removal And Replacement ............................. 40
CCB Circuit Board layout ................................................... 41
CCB Connection Identification
........................................... 42
Wiring Diagram .......................................................................... 44
CONTROl SySTEM OPERATION ................................................ 45
Overview .................................................................................... 45
Control System features .................................................... 45
Commercial And Residential Models .................................. 46
Control System Navigation .................................................. 46
User Input Buttons .............................................................. 46
Desktop Screen ................................................................... 46
Status Icons ........................................................................ 47
Operating States ................................................................. 48
Control System Menus .............................................................. 48
Temperatures ...................................................................... 49
Heater Status ...................................................................... 50
Display Settings .................................................................. 51
Heater Information .............................................................. 51
Current fault ....................................................................... 52
fault History ........................................................................ 52
fault Occurrence ................................................................. 52
Restore factory Defaults .................................................... 52
Service Contact Information ................................................ 53
Sequence Of Operation ............................................................. 54
Sequence Of Operation flow Chart .......................................... 55
TROUBlESHOOTING ................................................................... 56
Rough Starting/Rough Operation ........................................ 56
Not Enough Hot Water ........................................................ 56
Heater Status Menu ............................................................ 56
Things To Check Before Servicing ...................................... 56
Resetting The Control System ............................................ 56
Control System Unresponsive ................................................... 57
UIM (lCD) Is Blank ............................................................. 57
UIM Is Inoperable ................................................................ 57
fault Messages ......................................................................... 58
AC Reversed ....................................................................... 58
Temp Probe Open ............................................................... 58
Temp Probe Short ............................................................... 58
flame Sensor Short ............................................................ 59
flame Detect Error .............................................................. 59
Energy Cut Out (ECO) ........................................................ 60
Blocked Air Intake ............................................................... 61
Blocked Exhaust ................................................................. 62
Blower Prover failure .......................................................... 62
Blower Prover Open ............................................................ 63
low Igniter Current .............................................................. 64
Ignition failure ..................................................................... 65
Communication failure ....................................................... 66
