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

							51
SERVICE CONTACT INFORMATION
The control system has a discrete menu that Installing contractors and/or service agents can access to enter contact information for 
their customers. This contact information will be displayed with all Fault and Alert messages.
DESCRIPTION/ACTIONDISPLAY
From  the  Desktop  Screen  (see  Figure  52  on  page  44)  press 
and hold down the middle (unmarked) Operational Button for 30 
seconds and then release it.
This  will  launch  a  discrete  menu  where  personalized  contact 
information can be entered.
Using the UP and DOWN buttons select (highlighted in black) 
the "Show Contact Information" menu item.
Press the Operational Button under "CHANGE" to activate the 
adjustment mode for this parameter.
Show Contact Information   No
Change Contact Nam e
Change Contact Phone
Current Contact Info:
(000) 000-0000
Access Code
  CHANGE  BACK HELP
Service Contact Information
With the adjustment mode for "Show Contact Information" 
activated the selection bar will change from a black fill to a 
black outline.
Use the Up and Down Buttons to change the setting from 
"No" to "Yes" and press the Operational Button underneath 
"UPDATE" to save the new setting.
NOTE: The Access Code at the bottom of the Service Contact 
Information screen is for manufacturing engineering purposes 
only. There are no user settings or information accessed 
through this menu item. 
Show Contact Information   Yes
Change Contact Nam e
Change Contact Phone
Current Contact Info:
(000) 000-0000
Access Code
 UPDATE   CANCEL
Service Contact Information
Using the UP and DOWN buttons select (highlighted in black) 
the "Change Contact Name" menu item.
Press the Operational Button under "SELECT" to open the 
Change Contact Name menu.
Show Contact Information   Yes
Change Contact Nam e
Change Contact Phone
Current Contact Info:
(000) 000-0000
Access Code
 SELECT  BACK HELP
Service Contact Information
Follow the on screen instructions to enter your name or the 
name of your company. There is a maximum of 20 character 
spaces for this purpose.
When finished press the Operational Button "UPDATE" to save 
the new Contact Name. The control system will return to the 
discrete menu.
Enter the service contact below :
NAME: _
Use the   > and <   keys to move between
characters. Use the UP  and DOWN keys to
change the characte r. --
 <  > UPDATE--
Using the UP and DOWN buttons select (highlighted in 
black) the "Change Contact Phone" menu item and press the 
Operational Button under "SELECT".
Follow the on screen instructions to enter a new Contact Phone 
number and press the Operational Button under "UPDATE" to 
save the new phone number. 
When the new Contact Name and Contact Phone number 
have both been updated, press the Operational Button under 
"BACK" to return to the Desktop screen.
  BACK  HELP
Show Contact Information   Yes
Change Contact Nam e
Change Contact Phone
Current Contact Info:
YOUR COMP ANY NAME HERE
(123) 456-7890
Access Code Service Contact Information  
						

							52
PRIOR TO START UP
Installation  and  start  up  of  this  water  heater  requires  abilities 
and  skills  equivalent  to  that  of  a  licensed  tradesman  in  the  field 
involved, see Qualifications on page 6.
Do  not  place  the  water  heater  in  operation  if  any  part  has  been 
under  water.  Immediately  call  a  qualified  service  technician  to 
inspect  the  water  heater  and  to  replace  any  part  of  the  control 
system and any gas control which has been under water. 
Light  the  water  heater  in  accordance  with  the  Lighting  and 
Operation Instruction label on the water heater and in this manual 
on page 53.
The  water  heaters  covered  by  this  manual  are  equipped 
with  an  electronic  control  system  (see  page  44)  which  
automatically  sequences  the  Combustion  Blower,  pre  and  post 
purging of the combustion chamber, the spark generator, the 24 VAC 
Gas  Valve,  Main  Burner  ignition,  and  flame  sensing.  The  control 
system will lock out after three unsuccessful ignition attempts.
Before  attempting  start  up,  thoroughly  study  and  familiarize 
yourself  with  the  exact  Sequence  Of  Operation,  see  the  written 
Sequence  Of  Operation  on  page  56  and  the  Sequence  Of 
Operation Flow Chart on page 57.
Be certain that the water heater is full of water, that air is purged 
from  the  gas  and  water  lines  and  that  there  are  no  leaks  in  the 
gas and water lines. Ensure all inlet water valves are open.
FILLING THE WATER HEATER
Follow these steps to fill the water heater prior to start up.
1.  Close the heater drain valve.
2.  Open a nearby hot water faucet to permit the air in the system 
to escape.
3.  Fully open the cold water inlet valve allowing the piping and 
water heater to fill with water.
4.  Close the hot water faucet opened in Step 2 as water starts to flow.
INITIAL START UP
REQUIRED TEST EQUIPMENT
•  One U-tube manometer, recommended ranges; 0-14" W.C. 
(0--3.5 kPa) and 0-35" W.C. (0-8.7 kPa) or pressure gauges.
•  One  digital  manometer  can  be  used  in  place  of  U-tube 
manometers or pressure gauges. Recommended ranges; 
-14.00 to + 14.00" W.C. (0-3.5 kPa) resolution 0.01" W.C. 
and 0-35" W.C. (0-8.7 kPa) resolution 0.10" W.C. NOTE:  All  test  equipment  must  be  acclimated  to  ambient 
temperature before calibration and use.
PREPARATION
1. 
Using  the  control  system  menus,  change  the  Operating  Set 
Point  to  the  lowest  temperature  setting,  see  Operating  Set 
Point And Differential Adjustment on page 47.
2.  Turn the water heater’s Enable/Disable switch to the “Disable” 
position.
3.  Close the Main Gas Shut Off Valve, see Figure 47 on page 39.
4.  Wait five (5) minutes for any residual gas to clear.
5.  Connect  manometer  to  the  supply  gas  pressure  port  on  the 
gas valve see Figure 53. 
On the water heaters covered by this manual there are test ports 
for supply and manifold gas pressure readings on the gas valve. 
Using a small flat tip pocket screw driver - open the needle valve 
inside  the  supply  gas  pressure  test  port  one  full  turn  only;  turn 
the  needle  valve  screw  counter-clockwise  to  open  the  valve. 
Slide  the  manometer  sensing  tube  over  the  top  of  the  test  port, 
see Figure 53.
6.  Open the Main Gas Shutoff Valve.
7.  Measure  and  record    the  supply  gas  pressure,  this  is  a 
"static"  supply  gas  pressure  reading;  while  the  water  heater 
is  not  firing.  Adjust  supply  gas  pressure  as  necessary,  see 
Supply Gas Pressure Adjustment on page 54.
Figure 53
START UP  
						

							53
LIGHTING & OPERATION LABEL
The instruction label below is affixed to the water heater's covered by this manual at the factory and must be followed when lighting 
and operating the water heater.
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4.  Set the Enable/Disable switch on the control panel
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8.  Set the Enable/Disable switch on the control panel     to the Enable position.
2.  Set the Enable/Disable switch on the control panel     to the Disabl e position.
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D
 ENABLE/DISABLE
SWITCH 
FOR YOUR SAFETY READ BEFORE LIGHTING
WARNING: If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal injury  
or loss of life.
10.  lf the appliance will not operate, follow th e instructions  “TO TURN OFF GAS TO APPLIANCE”  and call your technician or gas supplier .  
						

							54
Gas Line Installation on page 39 and Supply Gas Regulator on 
page 13. Ensure all requirements and installation instructions 
are maintained.
CHECKING THE FIRING RATE
If  firing  rate  adjustment  is  required  follow  these  instructions  to 
determine the actual firing rate of the water heater:
NOTE:  The  heaters  covered  by  this  manual  are  capable  of 
modulating  their  firing  rate.  The  firing  rate  should  be  checked 
with the heater operating at it's full firing rate.
1. Ensure there are no other gas fired appliances connected to 
the gas meter firing during this test.
2.  Contact  the  gas  supplier  to  determine  the  heating  value,  in 
Btu per cubic foot, of the gas supply.
3.  Start the water heater and ensure it is firing.
4.  Locate the gas meter serving the water heater.
5.  Time how long (in seconds) it takes for one cubic foot of gas 
to be used while the water heater is firing with a stop watch.
6.  Use the formula below to “clock” the gas meter and determine 
the actual firing rate of the water heater based on the heating 
value (Btu per cubic foot) of the gas supply:
x  H  =  Btu/hr3600
T
x  1050  =  300,000 Btu/hr (87.9 kW)3600
12.6
Example:
•  3600 = seconds in one hour.
•  T = time, in seconds, to burn one cubic foot of gas.
•  H = heating value of gas in Btu per cubic foot. 
•  Btu/hr = actual firing rate of the water heater.
NOTE: 1050 Btu per cubic foot is a standard value for natural 
gas. Standard propane gas Btu content is 2500 Btu per cubic 
foot.  Btu  values  may  change  in  certain  areas  and  at  high 
elevations. Check with the local gas utility company.
TO TURN OFF GAS SUPPLY
1.  Change the Operating Set Point to the lowest temperature setting, 
see Operating Set Point And Differential Adjustment on page 47.
2.  When the water heater has completed its shut down sequence 
and  enters  the  standby  mode,  turn  the  water  heater’s  Enable/
Disable  switch  to  the  “Disable”  position.  When  in  the  "Disable" 
position  the  switch  only  removes  electrical  power  from  the 
gas  valve  so  that  water  heating  is  disabled. The  display,  CCB, 
and  other  electrical  components  will  still  be  energized  and  the 
display will read "Water Heating Disabled".
3.  Close the Main Gas Shutoff Valve, see Figure 47 on page 39.
SUPPLY GAS PRESSURE ADJUSTMENT
Fire and Explosion Hazar
d
Turn of f gas lines during installation.
Contact a qualified installer or servic e
agency for installation and service.
Excessive gas pressure to gas valve ca n
cause serious injury or death. Do not use water heater with any gas
other than the gas shown on the rating
label.  
Supply gas pressure shall be measured while the water heater is 
not firing (static pressure)  AND while the water heater is firing at 
full capacity (dynamic pressure). 
If the supply gas pressure to the water heater is not between 
the required minimum and maximum values given in Table 4 on 
page 10 adjust the supply gas regulator as necessary. Adjust 
the supply gas regulator(s) per the regulator manufacturer’s 
instructions  to  achieve  the  required  “static”  and  “dynamic” 
supply gas pressure.
Multiple Appliance Installations:
In  multiple  water  heater  installations  or  in  installations 
where  the  installed  water  heater(s)  share  a  common  gas 
supply main with other gas fired appliances; the supply gas 
pressures  shall  be  measured  at  each  water  heater  with  all 
gas  fired  appliances  connected  to  a  common  main  firing  at 
full capacity.
On  multiple  water  heater  installations  the  supply  gas  line 
regulators  shall  be  adjusted  to  provide  gas  pressure  to  each 
water heater within the minimum and maximum supply pressure 
requirements  listed  in  Table  4  on  page  10  with  all  gas  fired 
appliances  connected  to  a  common  gas  main  firing  at  full 
capacity.
NOTE:  A  pressure  drop  of  more  than  1.5”  W.  C.  (0.37  kPa) 
when the Main Burner ignites is an indication of an inadequate 
supply of gas and can lead to ignition failure, rough starts and/
or  rough  operation.  If  a  drop  of  more  than  1.5”  W.  C.  (0.37 
kPa)  in  supply  gas  pressure  occurs  when  the  Main  Burner 
ignites,  ensure  the  supply  gas  lines  and  regulator(s)  are 
properly sized and installed. See the requirements for Supply 
Gas Regulator and Supply Gas Line on page 13. See Supply   
						

							55
HIGH ALTITUDE INSTALLATIONS
Fire and Explosion Hazard
Gas and carbon monoxide detectors ar e
available.
Overfiring could result in fire or
explosion. Under no circumstances should the 
input exceed the rate shown on the 
water heater ’s rating label.  
Breathing Hazard - Carbon Monoxide Ga s
Breathing carbon  monoxide can cause brain  damage or
death.  Always read and understand  instruction  manual. Under no circumstances should
the input exceed the rate shown
on the water heater
’s rating label.  
Overfiring could result in damage to
the water heater and sooting.
Gas and carbon monoxide detectors
are available.
The water heaters covered by this manual are certified for 
use without modification for altitudes up to 10,100 feet.
Most  gas  utility  companies  de-rate  their  gas  for  high 
altitudes,  making  it  unnecessary  to  install  high  altitude 
orifices. 
For  installations  above  10,100  feet  call  the  technical 
support  phone  number  listed  on  the  back  cover  of  this 
manual  for  further  technical  assistance.  Call  the  local 
gas or utility company to verify Btu per cubic foot content 
before  calling  for  technical  assistance  and  have  that 
information available.
NOTE:  The actual firing rate of the water heater must not 
exceed the input rating on the water heater's rating label 
under any circumstances.
NOTE:  Due to the input rating reduction at high altitudes, 
the output rating of the water heater is also reduced and 
should be compensated for in the sizing of the equipment.  
						

							56
SEQUENCE OF OPERATION
Read  the  Sequence  of  Operation  below  before  attempting  to 
correct  any  operational  problems.  Refer  to  the  Features  And 
Components  section  beginning  on  page  7  for  the  location  of 
various  water  heater  components  described  below.  See  the 
Sequence Of Operation Flow Chart on page 57 also.
1. When the control system is first powered, during boot 
up,  it  will  display  water  heater  model  information 
during  initialization. After  a  few  moments  the  control 
system  LCD  which  is  part  of  the  UIM  (user  interface 
module)  will  display  the  default  screen  known  as  the 
"Desktop" screen.
2.  If  the  control  system  determines  that  the  actual  water 
temperature  inside  the  tank  is  below  the  programmed 
Operating  Set  Point  minus  the  Differential  setting,  a 
heating cycle is activated.
3.  The  control  system  then  performs  selected  diagnostic 
system  checks.  This  includes  confirming  the  low  gas 
pressure,  blocked  exhaust,  blocked  intake  and  ECO 
(energy  cut  out)  switch  contacts  are  closed.  The  Blower 
Prover Switch contacts are confirmed open.
4.  If  all  diagnostic  checks  are  successfully  passed,  the 
control system energizes the Combustion Blower for pre-
purge.
5.  The control system must confirm the Blower Prover Switch 
contacts close after the Combustion Blower is energized.
6.  If the Blower Prover Switch contacts are confirmed closed 
the control system energizes the spark ignition control.
7.  The  control  system  energizes  the  24  VAC  Gas  Valve 
allowing gas to flow to the Main Burner. 
8.  The  control  system  monitors  the  flame  sensor  to  confirm 
a  flame  is  present  at  the  Main  Burner.  If  a  flame  is  not 
verified  during  the  ignition  trial  period  the  control  system 
will  try  for  ignition  up  to  two  more  times.  If  flame  can 
not  be  verified  after  three  trials  for  ignition,  the  control 
system will lock out and display the “Ignition Failure” Fault 
message.
9.  If  a  flame  is  verified,  the  control  system  will  de-energize 
the  Spark  Ignition  Control  and  enter  the  heating  mode 
where it will continue heating the water until the Operating 
Set Point is reached. At this point, the control system will 
de-energize  the  24  VAC  Gas  Valve  and  enter  the  post-
purge cycle (approximately 30 seconds).
10.  The  water  heaters  covered  by  this  manual  are  capable 
of  modulating  their  firing  rate.  The  firing  rate  is  dictated 
by  the  hot  water  draw  and  various  other  temperature 
limitations.
11.  The Combustion Blower will run for the duration of the post-
purge  cycle  to  purge  the  water  heater  of  all  combustion  
gases. When the post-purge cycle is complete, the blower 
is de-energized and will coast to a stop.
12.  The  control  system  now  enters  the  standby  mode  while 
continuing  to  monitor  the  internal  storage  tank  water 
temperature and the state of other system devices. If the 
tank  temperature  drops  below  the  Operating  Set  Point 
minus the Differential setting, the control will automatically 
return to Step 2 and repeat the operating cycle.
TROUBLESHOOTING
INSTALLATION CHECKLIST
The list below represents some of the most critical installation 
requirements that, when overlooked, often result in operational 
problems,  down  time  and  needless  parts  replacement.  This 
is  not  a  complete  list.  Before  performing  any  troubleshooting 
procedures  use  the  list  below  to  check  for  installation  errors. 
Costs to correct installation errors are not covered under the 
limited  warranty.  Ensure  all  installation  requirements  and 
instructions in this manual have been maintained and followed.
WATER HEATER LOCATION
1. Ensure  proper  clearances  to  combustibles  are  maintained 
and there is sufficient room to service the water heater. See 
Clearances on page 11.
2.  Ensure the area is free of corrosive elements and flammable 
materials. See the instructions on page 16.
VENTING
1.  Ensure  the  intake  air  and/or  vent  (exhaust)  piping  is 
the  correct  size  for  the  installed  length.  See  Venting 
Requirements on page 22.
2.  Ensure  the  maximum  equivalent  feet  of  pipe  has  not  been 
exceeded  for  the  intake  air  and/or  vent  pipe.  See  Table 
7-PVC/CPVC and Polypropylene on page 22.
3.  Ensure  the  maximum  number  of  elbows  has  not  been 
exceeded  in  the  intake  air  and/or  vent  pipe.  See  Venting 
Requirements on page 22.
4.  Ensure the intake air screen is removed from the intake air 
connection  on  the  water  heater  when  installing  the  water 
heater in a Direct Vent configuration. See Figure 17 on page 
24.
5.  Ensure all exterior clearances for the intake air, vent,  concentric, 
and  low  profile  terminations  are  maintained.  See  Vertical 
Termination  Installation  on  page  24,  Sidewall  Termination 
Installation  on  page  26,  Concentric  Termination  Installation  on 
page 29, Low Profile Termination Installation on page 33. These 
clearances and those cited by local and national codes must be 
maintained.
GAS SUPPLY AND PIPING
1.  Ensure  a  supply  gas  regulator  has  been  installed  for  each 
water  heater.  See  the  requirements  for  a  Supply  Gas 
Regulator on page 13.
2.  Ensure  the  supply  gas  line  to  each  water  heater  meets 
the  minimum  supply  gas  line  size  requirements.  See  the 
requirements  for  the  Supply  Gas  Line  on  page  13  and  the 
installation instructions on page 39 and 40.
CONDENSATE DRAIN
Ensure  the  condensate  drain  is  properly  connected  to  the 
exhaust  elbow  on  the  water  heater  with  a  water  trap  to  prevent 
vent  gases  from  escaping  into  the  installed  space  and  draining 
freely  to  a  suitable  floor  drain.  See  Figure  9  on  page  16  and 
Condensate Drain Installation on page 38.
ELECTRICAL CONNECTIONS
1.  Ensure  the  power  supply  connections  to  the  water  heater 
are  polarity  correct.  See  the  requirements  for  the  Power 
Supply on page 13 and Electrical Wiring on page 40.
2.  Ensure  the  water  heater  is  properly  grounded.  Flame 
sensing  requires  an  adequate  earth  ground.  If  the  water 
heater is not properly grounded it will cause Ignition Failure.  
						

							57
SEQUENCE OF OPERATION FLOW CHART
YESNO
Water is  h eat ed to 
se t poin t24 VAC  Ga s Va lve
de -energi zed
Inter-Pu rge  cycl e24 VAC  Ga s Va lve
de- energ ized
Re trie s  up  to
tw o mo re time sPost-P urge  cycl e
Cont rol S yst em  
Loc ks Out
“I gni tion  Failure”  
Fa ult Ms g is 
di sp laye d
Wa ter heat er goes  
in to  sta ndby  mode
If ta nk te mp erat ure drop s bel ow Oper ating  Se t Po int mi nus 
Di fferen tial  se tting  a heati ng cycle  is  ac tiva ted
Bl ow er Prov er  sw itch  co ntac ts co nfirm ed 
cl os ed  by co ntro l syst em
Spark Ignition Control is energized.
24 VAC  Gas Va lve  is e nergi zed
gas fl ows to  Ma in Bu rner
Is fl ame sens ed at th e Ma in Bu rner ?
(contr ol syste m monito rs the flam e sens or)
C ont rol S yst em  Loc ks Out
Di sp lays  Fault Ms gNO
Cont rol S yst em  Loc ks Out
“B lowe r Pr ov er  Open ”
Fa ult Ms g is di sp laye d
NO
Co mb ustion  Blow er is energ ized
Pr e-Pu rge  cycl e
Contro l Sy stem  perf orms  di agnost ic ch ecks
No rmal St ate of all pres sure  sw itc hes  and  ECO are  checked
Bl ow er Prov er  pre ssu re sw itch  ve rified  open
Al l ot her  pres sure  sw itc hes  and  ECO are  verified  clos ed
Sequence is shown with Enable/Disable Switch in the Enable position
Figure 54  
						

							58
requirements (erratic gas supply volume/pressures) - see 
Supply Gas Regulator on page 13.
•  Excessive supply gas pressure - see Table 4 on page 10 
and Supply Gas Pressure Adjustment on page 54.
•  Vent (exhaust) gas recirculation at the vent and intake air 
pipe terminations on Direct Vent installations - see Direct 
Vent Installation on page 23.
•  Excessive equivalent lengths of intake air and/or vent 
(exhaust) piping installed - see Venting Requirements on 
page 22.
•  Debris clogging/blocking the intake air screen(s) - see 
Figure 17 on page 24 and Figure 22 on page 26.
•  Debris clogging/blocking the Main Burner - see Figure 2 on page 7.
MOMENTARY IGNITION
Burn Hazard
Do not reach into the burner housing or
combustion chamber if the water heater
is still hot.
Allow the water heater to cool and always use
gloves when handling the main burner . 
The combustion chamber and burner sleeve 
and housing become very hot during operation.
CAUTION
If  the  Main  Burner  ignites  momentarily  but  does  not  sustain 
ignition  allow  the  water  heater  to  try  to  ignite  up  to  two  more 
times until control system locks out and the Ignition Failure Fault 
message  is  displayed  on  the  control  system's  LCD.  If  the  water 
heater is experiencing rough starts - see Rough Starting, Rough 
Operation on this page. For momentary ignition problems without 
rough starting check the following:
•  Undersized supply gas line (low volume of supply gas) - see 
Supply Gas Line on page 39.
•  Supply gas regulator is not installed per installation 
requirements (erratic gas supply volume/pressures) - see 
Supply Gas Regulator on page 13.
•  See the list of possible causes and things to check and 
repair for the Ignition Failure Fault message on page 60.
•  Debris clogging/blocking the intake air screen(s) - see 
Figure 17 on page 24 and Figure 22 on page 26.
•  Debris clogging/blocking the Main Burner - see Figure 2 on 
page 7.
NOT ENOUGH OR NO HOT WATER •  No power to the water heater, check breaker or fuses.
•  Enable/Disable switch in "Disabled" position. Set to "Enable" 
to allow unit to operate.
•  Hot water supply valve(s) to fixtures closed.
•  Operating  Set  Point  is  set  too  low,  Differential  setting  is  set 
too high. See Control System Operation on page 44.
•  Tank Probe Offset is causing the heating cycles to terminate 
prematurely - see Temperatures Menu (cont) on page 48.
•  The heating capacity of the water heater has been exceeded, 
the water heater is unable to meet demand.
OPERATIONAL PROBLEMS
Read and understand this instructio n
manual and the safety messages
herein before installing, operating or
servicing this water heater .
Failure to follow these instructions and
safety messages could result in death
or serious injury.
This manual must remain with the
water heater .
This section of the manual is intended to be an aid in correcting 
common operational problems, it is not all inclusive. The installer 
may  be  able  to  observe  and  correct  certain  problems  which 
might  arise  when  the  water  heater  is  first  put  into  operation  or 
when  it  is  re-fired  after  a  prolonged  shutdown.  However,  only 
qualified service agents, as defined in Qualifications on page 6, 
using  appropriate  test  equipment,  should  perform  any  service 
procedures on the water heater. 
NOTE:  Call  the  technical  support  phone  number  listed  on  the 
back  cover  of  this  manual  for  further  technical  assistance  or  to 
locate a qualified service agent in your area.
INSTALLATION ERRORS
Operational problems on new installations are often the result of 
installation requirements that have been overlooked rather than 
failed  components.  IE:  A  "Low  Gas  Pressure"  Fault  condition 
is  most  often  caused  by  low  supply  gas  pressure  rather  than  a 
defective  Low  Gas  Pressure  switch.  Rough  starting  and  rough 
operation are often caused by undersized supply gas lines and/
or the absence of a supply gas regulator at the water heater.
Prior  to  performing  any  operational  checks  inspect  the  water 
heater  installation  to  ensure  all  installation  requirements  and 
instructions  have  been  maintained  and  followed.  See  the 
Installation Checklist on page 56.
NOTE: Costs to correct installation errors are not covered under 
the limited warranty.
ROUGH STARTING, ROUGH OPERATION
Fire and Explosion Hazar d
Turn of f gas lines during installation.
Contact a qualified installer or servic e
agency for installation and service.
Excessive gas pressure to gas valve ca n
cause serious injury or death. Do not use water heater with any gas
other than the gas shown on the rating
label.  
• Undersized supply gas line (low volume of supply gas) - see 
Supply Gas Line on page 13. 
•  Supply gas regulator is not installed per installation   
						

							59
ALERT CONDITIONS
When the control system declares an Alert condition it will display 
an Alert message on the control system's LCD with a question "?" 
mark.  The  water  heater  will  continue  to  operate  during  an Alert 
condition  but  the  water  heater  must  be  serviced  by  a  qualified 
service agent as soon as possible.
RESETTING CONTROL SYSTEM LOCK OUTS
To  reset  the  control  system  from  a  lock  out  condition;  turn  the 
electrical power supply off for approximately 20 seconds and then 
back on. Keep in mind; if the condition that caused the Fault has 
not been corrected, the control system will continue to lock out.
DIAGNOSTIC CHECKS
Turn of f power at the branch circuit
breaker serving the water heate r
before performing any service .
Electrical Shock Hazard

Label all wires prior to disconnecting
when performing service. Wiring error s
can cause improper and dangerous
operation.
Ve rify proper operation after servicing.
Failure to follow these instructions ca n
result in personal injury or death.
The following section, Fault And Alert Messages on page 60 and 
61,  lists  some  of  the  messages  the  control  system  will  display 
on  the  LCD  when  there  are  operational  problems.  This  is  not  a 
complete  list. Along  with  each  of  the  Fault  and Alert  messages 
described  there  will  be  a  list  of  possible  causes  and  things  to 
check and repair.
Only  qualified  service  agents,  as  defined  in  Qualifications  on 
page  6,  using  appropriate  test  equipment,  should  perform  any 
service procedures on the water heater. 
NOTE: If you are not qualified and licensed or certified as required 
by the authority having jurisdiction to perform a given task do not 
attempt  to  perform  any  of  the  diagnostic  or  service  procedures 
described in the following section. 
If you do not understand the instructions in the following section 
do not attempt to perform any procedures.
Call the technical support phone number listed on the back cover 
of  this  manual  for  further  technical  assistance  or  to  locate  a 
qualified service agent in your area.
Jumping out control circuits or components can
result in property damage, personal injury or death.
Service should only be performed by a qualified service
technician using proper test equipment.
Altering the water heater controls and/or wiring in any way
could result in permanent damage to the controls or water
heater and is not covered under the limited warranty .
Any bypass or alteration of the water
heater controls and/or wiring will result in voiding the appliance warranty .
• Colder  incoming  water  temperature  lengthening  the  time 
required to heat water to desired temperature.
•  Hot  water  piping  leaks,  open  faucets,  water  heater  drain 
valve leaking or open.
•  Sediment or lime scale accumulation may be affecting water 
heater operation. See Maintenance on page 62 for sediment 
and lime scale removal procedures.
•  Water heater not firing at full input rating. Check actual firing 
rate  of  the  water  heater,  see  instructions  on  page  54.  Note 
that  the  water  heaters  covered  by  this  manual  are  capable 
of  modulating  their  firing  rate.  The  firing  rate  is  dictated  by 
the hot water draw and various other temperature limitations.
WATER IS TOO HOT •  Operating Set Point is set too high. See Operating Set Point 
And Differential Adjustment on page 47.
•  If installed check Thermostatic Mixing Valve settings.
•  Tank Probe Offset setting improperly set - see Temperatures 
Menu (cont) on page 48.
•  Lime build-up on temperature probes. Inspect and clean.
•  Improper water piping - see diagrams beginning on page 68.
NOISY OPERATION •  Sediment  or  lime  scale  accumulations  can  cause  rumbling 
and  pounding  noises  during  heating  cycles.  See  the 
Maintenance section of this manual beginning on page 62 for 
sediment and lime scale removal procedures.
•  Normal operating noise of electrical components; Combustion 
Blower, transformer hum, relay contact closure.
WATER LEAKAGE IS SUSPECTED •  Ensure the water heater drain valve is tightly closed.
•  Check cleanout opening for leaks - see Figure 4 on page 9.
•  Check inlet/outlet water connections and system piping.
•  Check the Temperature-Pressure Relief Valve.
•  Excessive water temperature.
•  Excessive water pressure.
•  Defective Temperature-Pressure Relief Valve.
NOTE: Excessive water pressure is the most common cause of 
Temperature-Pressure  Relief  Valve  leakage.  Excessive  water 
system  pressure  is  most  often  caused  by  "thermal  expansion" 
in a "closed system." See Thermal Expansion and Closed Water 
Systems on page 14. The Temperature-Pressure Relief Valve is 
not intended for the constant relief of thermal expansion.
Temperature-Pressure  Relief  Valve  leakage  due  to  pressure 
build  up  in  a  closed  system  that  does  not  have  a  thermal 
expansion  tank  installed  is  not  covered  under  the  limited 
warranty.  Thermal  expansion  tanks  must  be  installed  on  all 
closed water systems.
REPLACEMENT PARTS
Replacement  parts  may  be  ordered  from  the  manufacturer, 
authorized service agencies or distributors. When ordering parts 
be sure to have the complete water heater Model Number, Serial 
Number  and  Series  Number  available.  This  information  can  be 
found on the rating label affixed to the water heater.
Refer  to  the  parts  list  included  with  the  water  heater  from  the 
factory  for  more  information  or  call  the  parts  department  or 
technical support phone number listed on the back cover of this 
manual for further assistance.
FAULT AND ALERT CONDITIONS
FAULT CONDITIONS
When the control system declares a Fault condition it will display a 
Fault message on the control system's LCD with an exclamation "!" 
mark. The control system will lock out and disable heating operation 
until the condition is corrected. The water heater must be serviced 
by a qualified service agent before operation can be restored.  
						

							60
FAULT AND ALERT MESSAGES
Call the technical support phone number listed on the back cover for further technical assistance or to locate a qualified service agent 
in your area.
POSSIBLE CAUSES - CHECK/REPAIRDISPLAYED FAULT/ALERT MESSAGE
• Using a manometer, ensure that gas supply pressure is above 
minimum requirement listed on heater’s data plate and does not 
drop more than 1.5” W.C.   when unit fires.
•  Ensure wire connections to gas valve are clean and tight.
•  Ensure wire connections to flame sensor are clean and tight.
•  Ensure wire connections to spark igniter are clean and tight.
•  Inspect flame sensor, clean/replace as needed.
•  Inspect spark igniter, realign igniter gap as needed
•   Ensure adequate electrical ground to heater.
 CHANGE  BACK ADV
ANCED
Ignition FailureFault occurred 2 mins ago
Flame not detected. Clean flame rod.  
Check gas supply .
Call a service professional:
Y our Company Name Here
(press [DOWN] for more.... )
• Confirm supply gas is turned on.
•  Using a manometer, ensure the supply gas pressure is above  
minimum pressure requirement listed on heater’s data plate  
before and during operation.
•  Ensure wire connections to gas pressure switch are clean and 
tight.
•  If all above conditions are met, replace gas pressure switch.
 CHANGE  BACK ADV
ANCED
Low Gas PressureFault occurred 2 mins ago
Gas pressure is below minimum 
required to operate this unit. Check 
gas pressure and switch .
Call a service professional:
Y our Company Name Here
(press [DOWN] for more.... )
• If Blocked Exhaust error occurs when blower is running, check for 
restrictions in exhaust pipe, including exhaust elbow, condensate 
drain, and outside termination. Also check exhaust pipe installation 
(size/length) per manual.
•  If Blocked Exhaust error occurs before blower runs, make sure 
pressure switch connections are clean and tight. Check pressure 
switch continuity/resistance. Switch should be closed (continuity/0 
ohms). Replace switch if open (no continuity).
•  Other possible causes: high wind conditions and excessive 
negative air pressure in building.
 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.... )