American Water Heater High Efficiency Commercial Gas HCG Series AHCG3 119T 300 THRU AHCG3 119T 500 Series 200 201 User Manual

							41
8. Route  the  control  wires  inside  the  junction  box  on  the  top 
of  the  water  heater;  see  Figure  3  on  page  8  to  locate  the 
junction  box.  Use  an  available  knock-out  to  route  the  wires 
inside the junction box.
9.  Install  field  supplied  control  wiring  and  conduit  as  required 
by  national  and  local  codes  between  the  water  heater’s 
junction  box  and  the  external  supervisory  control.  Connect 
the wiring from the external control to the control wires inside 
the junction box using wire nuts and electrical tape.
10.  Connect  the  control  wiring  to  a  set  of  dry  contacts  on  the 
external control. Follow the control manufacturer’s instructions 
for making connections.
11.  Restore power to the water heater.
12.  From  the  water  heaters  UIM  “Heater  Information  Screen” 
select    “Use  External  Enable”  and  change  to  “Yes”.  See 
Figure 3 on page 8 to locate the UIM.
NOTE:  Whenever  the  external  control  opens  the  set  of  dry 
contacts  used,  water  heating  operation  will  be  disabled. 
Whenever  the  external  control  closes  the  set  of  dry  contacts 
used, water heating operation will be enabled. A diagonal line and 
circle appears over the thermometer icon on the UIM when water 
heating operation is disabled. See the Status Icons descriptions 
in Table 16 on page 45.
NOTE:  Ensure  the  water  heater  is  protected  from  freezing 
temperatures when water heating operation is disabled. Damage 
to  the  water  heater  caused  by  freezing  temperatures  is  not 
covered under the limited warranty.
WATER LINE CONNECTIONS
The  water  piping  installation  must  conform  to  these  instructions 
and  to  all  local  and  national  code  authority  having  jurisdiction. 
Good practice requires that all heavy piping be supported.
Read  and  observe  all  requirements  in  the  following  sections 
before installation of the water piping begins:
1.  Mixing Valves on page 14.
2.  Dishwashing Machines on page 14.
3.  Temperature-Pressure Relief Valve on page 15.
4.  Closed Systems and Thermal Expansion on page 14.
5.  For  multiple  water  heater  installations  see  Water  Piping 
Diagrams beginning on page 68.
WATER PIPING DIAGRAMS
This  manual  provides  detailed  water  piping  diagrams  for  typical 
methods  of  application  for  the  water  heaters,  see  Water  Piping 
Diagrams beginning on page 68.
The  water  heater  may  be  installed  by  itself,  or  with  a  separate 
storage  tank.  When  used  with  a  separate  storage  tank,  the 
circulation may be either by gravity or by means of a circulating 
pump.  When  a  circulating  pump  is  used,  it  is  important  to  note 
that the flow rate should be slow so that there will be a minimum 
of turbulence inside the water heater storage tank.
Adjust  flow  by  throttling  a  full  port  ball  valve  installed  in  the 
circulating line on the outlet side of the pump. Never throttle flow 
on  the  suction  side  of  a  pump.  See  the  Water  Piping  Diagrams 
beginning on page 68.
NOTE: In addition to the factory installed Temperature-Pressure 
Relief  Valve  (T&P  valve)  on  the  water  heater,  each  remote 
storage tank that may be installed and piped to a water heating 
appliance  must  also  have  its  own  properly  sized,  rated  and 
approved Temperature-Pressure Relief Valve installed. 
Call  the  toll  free  technical  support  phone  number  listed  on  the 
back cover of this manual for further assistance in sizing a T&P 
valve for remote storage tanks.
NOTE:  If  electrical  connections  are  made  directly  to  the 
terminal  block  remove  the  jumper  wires  before  making 
connection.
5.  Connect the ground wire from the power supply to the green 
jumper  wire  or  the  ground  terminal  location  inside  of  the 
junction  box  located  on  top  of  the  water  heater.  If  the  green 
jumper  wire  is  used,  make  the  connection  inside  of  the 
junction box with a properly sized wire nut and wrap electrical 
tape  around  the  wire  nut  and  wire  end.  See  junction  box 
Figure 49 and wiring diagram Figure 58 on page 66.
6.  Replace the junction box cover when connections are complete.
NOTE: Do not apply power to the water heater before installation 
is complete and the water heater is filled with water.
Heater Wiring(Factory Installed)
MOVGround
Ground
Terminal
Jumper Wire
L1
Neutral
Figure 49
ENABLE/DISABLE CIRCUIT  
( For Building Management Systems)
The  water  heaters  covered  in  this  manual  are  equipped  with 
an  enable/disable  circuit  for  use  with  field  supplied  external 
supervisory controls such as time clocks or Building Management 
Systems.  The  enable/disable  circuit  may  be  used  to  disable 
heating operation during periods when the building is unoccupied 
or there is no demand for hotwater.
To  use  the  enable/disable  circuit  it  must  first  be  activated  by 
selecting the “Use External Enable” from the UIM. Field supplied 
wiring  is  then  installed  between  the  water  heater’s  CCB  and  a 
set  of  “dry  contacts”  (no  voltage  or  load)  on  the  field  supplied 
external control.
NOTE:  The  water  heater’s  enable/disable  circuit  is  a  switching 
circuit  only:  Do  not  apply  external  voltage  or  connect  any  load 
(IE:  relay  coil)  to  this  circuit.  This  will  damage  the  CCB  circuit 
board and is not covered under the limited warranty.
CONNECTING AN EXTERNAL SUPERVISORY CONTROL
The enable/disable circuit is accessed from the CCB’s J17 plug 
inside the CCB enclosure; see Figure 3 on page 8 to locate the 
CCB enclosure and Figure 57 on page 65 for the CCB layout. 
Install field wiring to the enable/disable circuit:
1.  Turn  off  power  at  the  water  heater’s  enable/disable  switch 
and the breaker that supplies power to the water heater.
2.  Locate the CCB enclosure.
3.  Carefully  remove  the  Temperature  Probe  connectors  and 
CCB enclosure cover.
4.  Locate pins 1 and 2 on the CCB J17 plug. See Figure 57 on 
page 65.
5.  Connect  the  two  field  supplied  control  wires  to  pins  1  and  2 
on the CCB J17 plug. 
6.  Thread  the  control  wires  out  of  the  CCB  enclosure  with  the 
other  wiring  and  carefully  replace  the  CCB  enclosure  cover. 
Ensure all wiring is routed through the intended area provided 
for strain relief. Ensure no wiring is being pinched.
7.  Reinstall the CCB enclosure cover.  
						

							42
This  water  heater  is  provided  with  a  properly  rated/sized  and 
certified  combination  temperature  -  pressure  (T&P)  relief  valve 
by the manufacturer. See Temperature-Pressure Relief Valve on 
page 15 for information on replacement and other requirements.
Water Damage Hazard
Temperature-Pressure Relief V alve discharge
pipe must terminate at adequate drain.
CAUTION
Install a discharge pipe between the T&P valve discharge opening 
and  a  suitable  floor  drain.  Do  not  connect  discharge  piping 
directly  to  the  drain  unless  a  6”  (15.2  cm)  air  gap  is  provided. 
To  prevent  bodily  injury,  hazard  to  life,  or  property  damage,  the 
relief  valve  must  be  allowed  to  discharge  water  in  adequate 
quantities should circumstances demand. If the discharge pipe is 
not connected to a drain or other suitable means, the water flow 
may cause property damage.
T&P Valve Discharge Pipe Requirements:
•  Shall not be smaller in size than the outlet pipe size of the 
valve, or have any reducing couplings or other restrictions.
•  Shall not be plugged or blocked.
•  Shall not be exposed to freezing temperatures.
•  Shall be of material listed for hot water distribution.
•  Shall be installed so as to allow complete drainage of both 
the Temperature-Pressure Relief Valve and the discharge 
pipe.
•  Must terminate a maximum of six inches above a floor 
drain or external to the building. In cold climates, it is 
recommended that the discharge pipe be terminated at an 
adequate drain inside the building.
•  Shall not have any valve or other obstruction between the 
relief valve and the drain.
THERMOMETERS (NOT SUPPLIED)
Thermometers are installed in the water piping system as a means 
of  detecting  the  temperature  of  the  hot  water  supply  at  critical 
points  in  the  system.  Field  supplied  thermometers  should  be 
obtained and installed. See Water Piping Diagrams on page 68.
WATER (POTABLE) HEATING AND SPACE HEATING
1. All  water  piping  components  connected  to  the  water  heater 
that  are  for  space  heating  applications  shall  be  suitable  for 
use with potable water.
2.  Toxic  chemicals,  such  as  those  used  for  boiler  treatment, 
must NEVER be introduced into this system.
3.  The  water  heaters  covered  in  this  manual  may  never  be 
connected  to  any  existing  heating  system  or  component(s) 
previously used with non-potable water heating appliance.
4.  When  the  system  requires  water  for  space  heating  that 
exceed safe temperatures at domestic water fixtures a mixing 
valve must be installed, see Mixing Valves on page 14.
5.  These  water  heaters  cannot  be  used  in  space  heating 
applications only.
T&P VALVE DISCHARGE PIPE
Explosion Hazard
Temperature-Pressure Relief  Valve
must comply with  ANSI Z21.22-
CSA 4.4 and  ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure .
Can cause serious injury or death.  
						

							43
TABLE 15
Water Temperature 
°F (°C) Time for 1st Degree Burn
 
(Less Severe Burns) Time for Permanent Burns
 
2nd & 3rd Degree  
(Most Severe Burns)
110 (43) (normal shower temp.)
116 (47) (pain threshold)
116 (47) 35 minutes 45 minutes
122 (50) 1 minute 5 minutes
131 (55) 5 seconds 25 seconds
140 (60) 2 seconds 5 seconds
149 (65) 1 second 2 seconds
154 (68) instantaneous 1 second
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15, 1978)The  water  heaters  covered  in  this  manual  are  equipped  with 
an  electronic  control  system  to  regulate  the  water  temperature 
inside the storage tank. The control system senses temperature 
from  two  factory  installed  temperature  probes,  one  installed  in 
the  top  of  the  storage  tank  and  one  installed  near  the  bottom, 
See Figure 3 on page 8 and Figure 4 on page 9 for location.
The “Operating Set Point” is adjusted to regulate water temperature 
inside  the  storage  tank.  This  is  an  adjustable  user  setting  in  the 
control system’s “Temperatures Menu.” This and all control system 
menus  are  accessed  through  the  UIM  (user  interface  module) 
located on the front of the water heater, see Figure 52.
The Operating Set Point is adjustable from 90°F (42°C) to 180°F 
(82°C).  The  factory  setting  is  120°F  (49°C).  See  Operating  Set 
Point And Differential Adjustment on page 47 for instructions on 
how to adjust the Operating Set Point and other user settings.
Set the Operating Set Point at the lowest setting which produces 
an acceptable hot water supply. This will always provide the most 
energy efficient operation.
MODULATION
The water heaters covered by this manual are capable of modulating 
their  firing  rate.  The  CCB  monitors  the  water  temperature  in  the 
tank and regulates the firing rate to achieve the target temperature 
setpoint. The firing rate is dictated by the hot water draw, proximity 
to  the  tank  temperature  setpoint,  and  various  other  temperature 
limitations. Periodically, when the heater is in modulation mode,  the 
CCB will increase the blower speed for a short period of time to clear 
out any condensation that has accumulated in the heat exchanger 
then decreases the blower speed back to the modulating firing rate 
required  to  maintain  the  desired  tank  temperature  setpoint.  This 
ramping  up  and  down  of  the  blower  speed  is  considered  normal 
operation of the water heater.
HIGH TEMPERATURE APPLICATIONS
Higher  operating  temperatures  cause  more  wear  on  all  water 
heaters and will decrease the life span of the water heater. Consider 
installing  a  small  booster  water  heater  for  high  temperature 
applications,  such  as  commercial  dishwashers,  to  raise  the  outlet 
temperature  from  the  larger  primary  water  heater  to  the  desired 
point of use temperature.
Contact your local distributor or call the technical support phone number 
listed on the back cover of this manual for further technical assistance.
Tank  Temperature   103°F
Operating Set Point   120°F
Status: Heating
MENU HELP
UP
DN
GASOFF
ON
MANUF ACTURER / MODEL  INFORMATION
Figure 50
HIGH TEMPERATURE LIMIT CONTROL (ECO)
This water heater is equipped with an ECO (energy cut off) non 
adjustable high temperature limit switch. The ECO is a normally 
closed switch that opens (activates) on a rise in temperature.
The ECO is located inside the Upper Temperature Probe (two red 
wires), see Figure 3 on page 8 for location. The ECO switch contacts 
will  open  when  the  water  temperature  reaches  approximately 
202°F (94°C) and close at approximately 140°F (49°C). 
If  the  ECO  activates  (contacts  open)  due  to  abnormally  high 
water  temperatures  in  the  storage  tank  the  control  system  will 
immediately  de-energize  the  24  VAC  Gas  Valve  and  end  the 
current heating cycle. The control system will "lock out" disabling 
further  heating  operation.  The  control  system  will  display  the 
"Energy  Cut  Out  (ECO)"  Fault  message  on  the  LCD  screen. 
It  is  important  that  a  Qualified  Service  Agent  be  contacted  to 
determine the reason for the ECO activation before resetting the 
ECO.  Once  the  reason  has  been  determined  and  corrected  the 
ECO can be reset as follows:
Should the ECO activate, the water temperature must drop below 
140°F  (49°C)  before  the  control  system  can  be  reset.  Once  the 
water temperature has cooled below this point the power supply 
to the water heater must be turned off and on again to reset the 
control system.
THERMOSTAT CONTROL
Water temperature over 125°F (52°C)
can cause severe burns instantly
resulting in severe injury or death.
Children, the elderly and the
physically or mentally disabled are at
highest risk for scald injury .
Feel water before bathing or
showering.
Te mperature limiting devices such as
mixing valves must be installed
when required by codes and to
ensure safe temperatures at fixtures.
Hot  water  temperatures  required  for  automatic  dishwasher  and 
laundry use can cause scald burns resulting in serious personal 
injury  and/or  death.  Table  15  shows  the  approximate  time-to-
burn relationship for normal adult skin.
The temperature at which injury occurs varies with the person’s 
age  and  duration  of  exposure.  The  slower  response  time  of 
children,  the  elderly  or  disabled  persons  increases  the  hazards 
to them. If anyone using hot water provided by the water heater 
being  installed  fits  into  one  of  these  groups  or  if  there  is  a  local 
code  or  state  law  requiring  a  certain  water  temperature  at  the 
point of use, then special precautions must be taken.
In addition to using the lowest possible temperature setting that 
satisfies  the  demand  of  the  application  a  mixing  valve  can  be 
installed at the water heater (see Figure 8 on page 14) or at the 
hot water taps to further reduce system water temperature.
Never allow small children to use a hot water tap or draw their own 
bath water. Never leave a child or disabled person unattended in 
a bathtub or shower. 
The water heater should be located in an area where the general 
public does not have access to set temperatures.
Setting  the  Operating  Set  Point  at  120°F  (49°C)  will  reduce  the 
risk  of  scalds.  Some  States  require  settings  at  specific  lower 
temperatures.
TEMPERATURE REGULATION  
						

							44
CONTROL SYSTEM OPERATION
Tank  Temperature   103°F
Operating Set Point   120°F
Status: Heating
MENU HELP
GASOFF
ON
MANUF ACTURER / MODEL  INFORMATIONLCD Screen
Information
Display
Status Icons
3 Operational buttons:
enter/exit menus,
select menu items,
activate adjustment modes,
confirm/cancel changes. Up & Down buttons:
navigate menus,
adjust user settings Title Bar
Enable/Disable Switch
Operational buttons are multi functional.  Their current function is defined by
the text that appears directly above each button on the LCD screen.
UIM (user interface module)
Desktop Screen Shown
UP
DN
Figure 52
OVERVIEW
The  water  heaters  covered  in  this  manual  are  equipped  with  an 
electronic control system that regulates water temperature inside 
the storage tank. Heating cycles and ignition are managed by the 
control system. The ECO (energy cut out), flame sensor, pressure 
switches  and  temperature  probes  are  monitored  by  the  control 
system.  The  Combustion  Blower,  spark  ignition  control,  24  VAC 
Gas Valve and anode rods are all powered by the control system. 
The  main  components  of  the  control  system  are  a  UIM  (user 
interface  module)  and  a  CCB  (central  control  board).  The  UIM  is 
located on the top front side of the water heater. The CCB is mounted 
on top of the water heater inside a protective enclosure. This unit is 
equipped with an Enable/Disable switch. To operate unit, make sure 
the switch is set to Enable. See Features And Components on page 
7 for location of these and all water heater components.
POWER
SUPPLY
BOARD
TRANSFORMER
CCBBOARD
Figure 51
CONTROL SYSTEM NAVIGATION
All  operational  information  and  user  settings  are  displayed  and 
accessed  from  the  UIM.  The  UIM  houses  the  control  system's 
LCD  (liquid  crystal  display)  and  five  snap  acting  (momentary) 
user  input  buttons;  an  up,  down  and  three  (3)  multi  functional 
operational buttons below the LCD, see Figure 52. User Input Buttons
•  The up and down buttons are used to navigate menus and 
adjust user settings. 
•  The operational buttons are used to enter/exit menus, 
select menu items, activate adjustment modes and confirm 
or cancel new user settings. The operational buttons are 
multifunctional, their current function is defined by the text 
that appears directly above each button on the LCD screen. 
THE DESKTOP SCREEN
During  normal  operation  the  control  system  will  display  the 
"Desktop"  screen  on  the  LCD  which  is  the  default  screen.  The 
control system will return to the Desktop screen when there are 
no  active  Fault  or  Alert  conditions  or  when  there  has  been  no 
user input for several minutes.  •  Manufacturer and water heater model information is 
displayed in Title Bar at the top of the Desktop screen. 
Menu titles are displayed in the Title Bar when navigating 
the control system menus.
•  The first temperature shown on the Desktop screen, Tank 
Temperature, is the temperature of the water inside the 
water heater's storage tank. 
•  The second temperature shown on the Desktop screen 
is the Operating Set Point. The Operating Set Point is the 
temperature at which the control system will maintain the 
water inside the storage tank. 
•  Beneath the Operating Set Point is the "Status" line. The 
Status line shows the current operational state of the 
control system in real time, see Table 17 on page 46 for a 
description of the various operational states.
•  The Desktop screen also displays animated "Status Icons" 
to convey operational information, see Table 16 on page 45 
for descriptions of the Status Icons.  
						

							45
STATUS ICONS
The Status Icons are displayed on the Desktop screen and convey operational and diagnostic information. The icons are described 
in the table below. See Figure 54 on page 57 and the Sequence Of Operation on page 56. 
TABLE 16
IconDescription
Water  temperature  in  the  tank  has  fallen.  Shaded  area  of  the  animated  thermometer  icon  will  rise  and  fall  in  response  to 
water temperature in the storage tank as sensed from the Upper and Lower Temperature Probes. See Figure 3 on page 8 
and Figure 4 on page 9 for location of Temperature Probes.
Water temperature in the tank has reached the Operating Set Point. The control system enters the Standby mode.
The control is unable to initiate a heating cycle. This will happen whenever a Fault condition is detected by the control system 
or  when  the  Enable/Disable  switch  on  front  panel  is  in  disable  position  or  Building  Management  system  Enable/Disable 
circuit is an open circuit. Display will read "Status: Water Heating Disabled". For more information see Enable/Disable Circuit 
on page 41.
The Combustion Blower is being energized.
The Blower Prover pressure switch contacts have closed. The check mark icon is visual confirmation of contact closure. See 
Figure 3 on page 8 for Blower Prover Switch location.
The spark igniter is being energized. See Figure 2 on page 7 for spark igniter location.
GAS
OFF
ONThe 24 VAC Gas Valve is being energized.
The control system has sensed flame at the Main Burner from the flame sensor. See the Sequence Of Operation Flow Chart 
on page 57 and Figure 2 on page 7.
The  control  system  has  declared  a  Fault  condition  and  must  be  inspected/serviced  by  a  Qualified  Service  Agent.  Fault 
message details can be viewed in the Current Fault menu. Heating operation is disabled (lock out) until the condition that 
caused the Fault is corrected. Power to the water heater must be cycled off and on at the breaker to reset the control system. 
NOTE: Cycling power will not reset the control system if the condition that caused the Fault has not been corrected.
The control system has declared an Alert condition and must be inspected/serviced by a Qualified Service Agent. The water 
heater will continue to operate during an Alert condition.  
						

							46
OPERATING STATES
The current operational state of the water heater is displayed on the Desktop screen as the "Status." The common operational states 
are described in the table below.  See Figure 54 on page 57 and the Sequence Of Operation on page 56.
TABLE 17
StateDescription
Standby The water heater is not in an active heating cycle. IE: the Tank Temperature is at or above the Operating Set Point.
Input Verification The control system is conducting a diagnostic check at the beginning of a heating cycle.
Water heating 
disabled A Fault condition is detected by the control or when the Enable/Disable switch on front panel is in disable position or the 
Building Management system Enable/Disable is an open circuit.
Pre-Purge The Combustion Blower is energized to flush residual flue gases from the combustion chamber prior to ignition.
Spark Igniter 
Energized The Spark Igniter is energized.
Ignition Activation The 24 VAC Gas Valve is energized and opens to allow fuel gas to flow to the Main Burner.
Ignition Verification The control system is monitoring the flame sensor for the required minimum flame sensing current.
See the Sequence Of Operation on page 56 for minimum flame sensing current (DC micro amps) information.
Inter-Purge The Combustion Blower is energized to flush residual fuel gas from the combustion chamber after a failed ignition attempt.
Heating Ignition was successful, flame sensing current has been established.  The water in the storage tank is being heated.
Post-Purge The Combustion Blower is energized to flush residual flue gases from the combustion chamber at the end of a heating 
cycle.
Fault The control system has detected a Fault condition. Heating operation is disabled until the Fault condition is corrected. 
Power to the water heater must be cycled off and on at the breaker to reset the control system. 
NOTE: Cycling power will not reset the control system if the condition that caused the Fault has not been corrected.
CONTROL SYSTEM MENUS
From the Desktop screen pressing the Operational button directly below "Menu" on the LCD will display the "Main Menu" this is where 
all control system menus are located. The table below describes the control system menus.
TABLE 18
Menu
Description
Temperatures Most commonly accessed menu. Contains the Operating Set Point and Dif ferential user settings.
Heater Status This  menus  displays  the  current  state  of  all  pressure  switches  and  the  ECO  (open/closed).  The  on/off  status  of  the 
Combustion Blower, gas valve, spark igniter, flame sensor and other monitored water heater components are displayed 
in this menu.
Display Settings Temperature  units  (°F  or  °C),  the  LCD  appearance  (brightness/contrast)  and  backlight  delay  user  adjustable  settings 
are located in this menu.
Heater Information Elapsed  time  of  operation,  total  heating  cycle  time,  heating  cycle  count,  heating  on  time  along  with  UIM  and  CCB 
software revisions can be viewed in this menu.
Current Fault Displays any current Alert or Fault messages.
Fault History This  control  system  menu  retains  a  list  of  the  last  nine  (9)  Fault  and Alert  messages  with  a  time  stamp.  The  newest 
event will replace the oldest. Faults will clear after 30 days.
Fault Occurrence This control system menu retains a running total of how many times each Fault condition has occurred since the water 
heater was first installed. This screen does not clear and the information can not be reset.
Restore Factory Defaults This  control  system  feature  allows  the  user  to  restore  control  system  user  settings  to  their  factory  default  settings. 
Display Settings preferences ARE NOT changed when factory defaults are restored.
Help Screens Text based operational and user information explaining how to change user settings, navigate the control system menus 
and icon descriptions.  
						

							47
USER SETTINGS & CONTROL SYSTEM MENUS
TEMPERATURES MENU
Operating Set Point And Differential Adjustment
The  Operating  Set  Point  is  adjustable  from  90°F  (42°C)  to  180°F  (82°C).  The  factory  setting  is  120°F  (49°C).  The  Differential  is 
adjustable  from  2°  to  20°. The  factory  setting  is  8°. These  user  settings  are  accessed  from  the Temperatures  menu. The  following 
instructions will explain how to adjust these settings and navigate the control system menus.
When the water temperature sensed by the control system from the two (upper and lower) Temperature Probes reaches the Operating 
Set Point the control system will end the heating cycle. A heating cycle will be activated again when the sensed water temperature 
drops below the Operating Set Point minus the Differential setting.
NOTE:  Lower  Differential  settings  may  cause  excessive  heating  cycles  (short-cycling)  which  can  cause  premature  failure  of 
components  such  as  the  Hot  Surface  Igniter.  Set  the  Differential  at  the  highest  setting  which  produces  an  acceptable  hot  water 
supply. Set the Operating Set Point to the lowest setting which produces an acceptable hot water supply for most efficient use.
DESCRIPTION/ACTIONDISPLAY
From the Desktop screen, press the Operational Button under 
MENU. The "Main Menu" screen will be displayed.
Ta nk  Temperature   120°F
Operating Set Point   120°F
Status: Standby
MENUHELP
MANUF ACTURER / MODEL INFORMA TION
The Main Menu is where all control system menus are listed, 
see Table 18 on page 46 for a complete list and description of 
control system menus. Use the Up and Down Buttons to view 
all control system menus from the Main Menu.
With Temperatures menu selected (highlighted in black) in 
the Main Menu screen, press the Operational Button under 
“SELECT” to enter the Temperatures menu.
If the Temperatures menu is not selected use the Up and Down 
Buttons to select this menu item.
Temperatures
Heater Status
Display Settings
Heater Information
Current Fault
 SELECT  BACK HELP
Main Menu
With the Operating Set Point selected in the Temperatures 
menu, press the Operational Button underneath “CHANGE” to 
activate the adjustment mode for this menu item.
If Operating Set Point is not selected use the Up and Down 
Buttons to select this menu item.
NOTE: Higher Temperature settings increase wear and 
operating costs. Set the Operating Set Point to the lowest 
setting which produces an acceptable hot water supply. This 
will always provide the most energy efficient operation and 
longer life.
Operating Set Point   120°F
Dif ferential   8°F
Ta nk  Temperature   120°F
Ta nk Probe Of fset   0°F
 CHANGE BACK HELP
Temperatures
With the adjustment mode for the Operating Set Point activated 
the selection bar will change from a black fill to a black outline.
Use the Up and Down Buttons to change the current setting.
Press the Operational Button under "UPDATE" to save the 
new setting. Press the Operational Button under "CANCEL" to 
discard changes and return to the previously saved setting.
NOTE: Use this same procedure to change the Differential 
setting and other adjustable user settings in the control system 
menus.
Operating Set Point   140°F
Dif ferential   8°F
Ta nk  Temperature   120°F
Ta nk Probe Of fset   0°F
 UPDATE  CANCEL
Temperatures  
						

							48
TEMPERATURES MENU (CONT)
DESCRIPTION/ACTIONDISPLAY
•  Differential  - Adjustable user setting that changes the tank 
temperature  differential  with  a  range  of  2°  to  20°F.  The 
factory setting is 8°F.
•  Tank Temperature - non adjustable - control system sensed 
temperature  (averaged  from  upper  and  lower  temperature 
probes).
•  Tank Probe Offset  -  adjustable  user  setting,  range  -5°  to 
+5° (factory setting 0°). 
NOTE: These  settings  should  only  be  used  if  the  hot  water 
supply  temperature  varies  greatly  from  the  Operating  Set 
Point setting. 
The  Tank  Probe  Offset  is  used  to  calibrate  control  system 
temperature  sensing.  This  can  improve  the  precision  of 
temperature control in the storage tank and at points of use. 
This  feature  can  also  be  used  to  compensate  for  building 
recirculation  loops  (hot  water  returning  to  the  storage  tank) 
that may cause the heating cycles to terminate prematurely.
Example:  If  the  current  sensed  temperature  from  a 
temperature probe is 120°F (49°C) and the Offset setting for 
that  probe  is  adjusted  to  a  value  other  than  0°,  the  control 
system  would  calibrate  or  “offset”  the  sensed  temperature 
from the probe and the averaged tank temperature. Heating 
cycles  would  be  activated  and  deactivated  based  on  the 
calibrated  (offset)  temperature.  A  -5°  setting  results  in  +5° 
hotter water.
These  settings  are  adjusted  in  the  same  way  described 
for  the  Operating  Set  Point  And  Differential  Adjustment  on   
page 47.
Operating Set Point   140°F
Dif ferential   8°F
Ta nk  Temperature   120°F
Ta nk Probe Of fset   0°F
 CHANGE BACK HELP
Temperatures
HEATER STATUS MENU
DESCRIPTION/ACTION DISPLAY
Select  Heater  Status  from  the  Main  Menu  and  press  the 
Operational  Button  under  "SELECT"  to  enter  this  menu.  This 
menu contains non adjustable operational information. Use the 
Up & Down Buttons to navigate the menu. •  Status - displays the current Operating State, see Table 17 
on page 46.
•  ECO Contact, Low Gas PS , Blocked Inlet PS, Blocked 
Outlet PS , Blower Prover PS - displays the current state 
of the switch contacts; open or closed.
•  Igniter On , Gas Valve On - displays whether or not the 
control system is currently energizing these water heater 
components; yes = energized, no = de-energized.
•  Flame Detected  - displays whether or not the control 
system has detected Main Burner flame during ignition from 
the flame sensor.
NOTE: Menu display is shown with Enable/Disable switch in 
Enable position. Top of Menu
Status  
Standby
ECO Contact   Closed
Low Gas PS   Closed
Blocked Inlet PS   Closed
Blocked Outlet PS   Closed
Blower Prover PS   Open
Igniter On   No
  BACK HELP
Heater Status
Bottom of Menu
Gas Valve On   No
Flame Detected   No
  BACK HELP
Heater Status  
						

							49
DISPLAY SETTINGS
DESCRIPTION/ACTIONDISPLAY
Select  Display  Settings  from  the  Main  Menu  and  press  the 
Operational  Button  under  "SELECT"  to  enter  this  menu.  This 
menu contains adjustable display options for viewing information 
on  the  UIM’s  LCD  screen.  Use  the  Up  &  Down  Buttons  to 
navigate the menu. •  Temperature Units  - Adjustable user setting that changes 
temperature units display to Celsius °C or Fahrenheit °F.
•  Backlight Delay - Adjustable user setting that determines 
how long the UIM’s LCD backlight remains illuminated after 
a key has been pressed. Available settings are; Always Off, 
10, 30 or 60 seconds and Always On.
•  Contrast - Adjustable user setting to adjust the UIM’s LCD 
screen contrast between text and background.
NOTE:  These  settings  are  adjusted  in  the  same  way 
described  for  the  Operating  Set  Point  And  Differential 
Adjustment on page 47.
Te mperature Units   °F
Backlight Delay   30s
Contrast   60%
 CHANGE BACK HELP
Display Settings
HEATER INFORMATION
DESCRIPTION/ACTION DISPLAY
Select  Heater  Information  from  the  Main  Menu  and  press  the 
Operational  Button  under  "SELECT"  to  enter  this  menu.  This 
menu contains non adjustable operational information. •  Elapsed Time  - Total  accumulated  time  the  control  system 
(water heater) has been energized.
•  Burner On Time - Total accumulated time the control system 
has been in the heating operating state; burner run time.
•  Total Cycle Count  -  Total  accumulated  count  of  heating 
cycles.
•  CCB Version - Software version for central control board.
•  UIM Version - Software version for user interface module.
•  Config  CRC  -  Verifies  the  configuration  key  matches  the 
CCB programming.
•  Use External Enable -  Enables/Disables  the  external 
enable circuit.
•  External Enable Status -  displays  whether  or  not  the 
external enable circuit has been activated.
•  Ignition Trials - displays the number of ignition trials allowed.
NOTE:  Historical  data  is  stored  in  the  configuration  key.  If 
this 'key' is replaced during servicing the historical data will 
be lost. The data stored in the new configuration key will no 
longer reflect the entire history of the water heater.
The Elapsed Time, Burner On Time and Cycle Count indicate 
age, usage and wear.
If  the  Cycle  Count  per  day  is  high  (divide  cycle  count  by 
days  to  determine  cycles  per  day)  or  the  cycle  duration  is 
short (determine burner on time total minutes, divide burner 
on  time  total  minutes  by  cycle  count)  consider  rasing  the 
Differential  setting  to  avoid  short  cycling  and  excessive 
component  wear,  see  Operating  Set  Point  And  Differential 
Adjustment on page 47.
This  historical  data  can  also  be  used  to  assist  facilities 
managers in forecasting planned replacement of equipment 
to help avoid lengthy and costly hot water supply interruptions.
Elapsed  Time
   10 day 0 hrs 0 mins
Burner On  Time
   5 hrs 22 mins
To tal Cycle Count   00000035
CCB V ersion   X.XX
Config CRC   0 x 605D
 CHANGE BACK HELP
Heater Information
UIM Version   X.XX
Use External Enable   No
External Enable Status   No
Ignition  Trials   3
  BACK HELP
Heater Information  
						

							50
CURRENT FAULT
DESCRIPTION/ACTIONDISPLAY
Select  Current  Fault  from  the  Main  Menu  and  press  the 
Operational  Button  under  "SELECT"  to  enter  this  menu.  This 
menu contains non adjustable operational information. Use the 
Up & Down Buttons to navigate the menu.
This  menu  contains  the  current  Fault  or  Alert  error  message. 
The  time  the  Fault  or Alert  message  occurred  appears  directly 
below. A brief description of what causes the particular Fault or 
Alert  condition  appears  below  that.  Pressing  the  Operational 
Button  under  "ADVANCED"  will  give  more  detailed  service 
information  and  a  list  of  possible  causes  for  the  Fault  or  Alert 
condition.  See  Fault And Alert  Messages  on  page  59  for  more 
detailed information and diagnostic procedures.
If  there  is  no  Fault  or  Alert  condition  active  this  menu  will  not 
contain any information, "(none)" will be shown next to Current 
Fault in the Main menu.
 CHANGE  BACK ADV
ANCED
Blocked Exhaus tFault occurred 2 mins ago
Restriction in exhaust pipe.
Check exhaust pipe and
termination for blockage.
Call a service professional:
Your Company Name Here
(press [DOWN] for more.... )
FAULT HISTORY
DESCRIPTION/ACTION DISPLAY
Select  Fault  History  from  the  Main  Menu  and  press  the 
Operational  Button  under  "SELECT"  to  enter  this  menu.  This 
menu contains non adjustable operational information. Use the 
Up & Down Buttons to navigate the menu.
This  menu  contains  a  list  of  the  last  nine  (9)  Fault  and  Alert 
messages with a time stamp. The newest event will replace the 
oldest.
Press  the  Operational  Button  under  "VIEW"  to  view  details  for 
each Fault or Alert message stored.
1:   Blocked Air Intake (A7)
   51 mins ago
2:   Blocked Exhaust (A8 )
   54 mins ago
3:   Low Gas Pressure (A6 )
   57 mins ago
4:   Blower Prover Failure (AC )
 VIEW BACK HELP
Fault History
FAULT OCCURRENCE
DESCRIPTION/ACTION DISPLAY
Select  Fault  Occurrence  from  the  Main  Menu  and  press  the 
Operational  Button  under  "SELECT"  to  enter  this  menu.  This 
menu contains non adjustable operational information. Use the 
Up & Down Buttons to navigate the menu.
This  menu  contains  a  running  total  of  how  many  times  each 
Fault  condition  has  occurred  since  the  water  heater  was  first 
installed.
NOTE:  Historical data is stored in the Configuration Key. If this 
'key' is replaced during servicing the historical data will be lost. 
The  data  stored  in  the  new  configuration  key  will  no  longer 
reflect the entire history of the water heater.
Ignition Failure   10
ECO   0
Low Gas Pressure   10
Blocked Intake  Air   0
Blocked Exhaust   0
Blower Prover   0
Flame Detect Error   3
  BACK HELP
Fault Occurrence
RESTORE FACTORY DEFAULTS
DESCRIPTION/ACTION DISPLAY
Select Restore Factory Defaults from the Main Menu and press 
the Operational Button under "SELECT" to enter this menu.
To  restore  the  adjustable  user  settings  to  their  factory  default 
settings  press  the  Operational  Button  underneath  “YES.”  The 
display  will  show  text  confirming  the  factory  default  settings 
have been restored.
Press  the  Operational  Button  underneath  “BACK”  to  exit  the 
Restore Factory Defaults menu.
 YES   NO
Restore Factory Default s
Are you sure you want to
restore the system to factory
defaults?