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