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...

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...

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...

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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...

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...

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...

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...

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...

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...

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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...