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

							11
LOCATING THE WATER HEATER
Carefully choose a location for the new water heater. The placement 
is a very important consideration for the safety of the occupants in 
the building and for the most economical use of the water heater.
Property Damage Hazard
All water heaters eventually leak.Do not install without adequate drainage.
CAUTION
Whether replacing an existing water heater or installing the water 
heater in a new location observe the following critical points:
1. The water heater must be located indoors.
2.  The water heater must not be located in an area where it will 
be subject to freezing temperatures.
3.  Locate the water heater so it is protected and not subject to 
physical damage by a moving vehicle.
4.  Locate the water heater on a level surface.
5.  Locate the water heater near a floor drain. The water heater 
should  be  located  in  an  area  where  leakage  of  the  tank  or 
connections  will  not  result  in  damage  to  the  area  adjacent 
to the water heater or to lower floors of the structure. When 
such locations cannot be avoided, it is recommended that a 
metal drain pan, adequately drained, be installed under the 
water heater.
6.  Locate the water heater close to the point of major hot water usage.
7.  Locate  the  water  heater  close  to  a  120  VAC  power  supply. 
See Power Supply on page 13 for requirements.
8.  Locate  the  water  heater  where  an  adequate  supply  of  fresh 
air  for  combustion  and  ventilation  can  be  obtained.  See Air 
Requirements on page 17.
9.  Locate the water heater where the vent and intake air piping, 
when  installed,  will  remain  within  the  maximum  equivalent 
lengths allowed. See Venting Requirements on page 22.
10.  Do  not  locate  the  water  heater  where  noise  (such  as 
the  Combustion  Blower)  during  normal  operation  will  be 
objectionable in adjacent areas.
11.  Do  not  locate  the  water  heater  where  the  subsequent 
installation  of  the  vent  (exhaust)  or  intake  air  terminations 
would  be  objectionable  due  to  noise  at  the  termination(s). 
This includes locations close to or across from windows and 
doors. See Venting Installation on page 21.
Fire or Explosion Hazar d
Read instruction manual befor e
installing, using or servicing water heater .
Avoid all ignition sources if you smell gas .
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
Use only the gas shown on the water heater rating label.
Keep ignition sources away from faucets after extended
periods of non-use. Maintain required clearances to combustibles. Do not expose water heater controls to excessive gas
pressure.
There is a risk in using fuel burning appliances such as gas water 
heaters in rooms, garages or other areas where gasoline, other 
flammable  liquids  or  engine  driven  equipment  or  vehicles  are 
stored, operated or repaired. Flammable vapors are heavy and 
travel  along  the  floor  and  may  be  ignited  by  the  water  heater’s 
igniter or Main Burner flames causing fire or explosion.
Flammable items, pressurized containers or any other potential 
fire  hazardous  articles  must  never  be  placed  on  or  adjacent  to 
the water heater.
CLEARANCE TO COMBUSTIBLE MATERIALS
The  water  heaters  covered  in  this  manual  are  approved  for 
installation on combustible flooring. The clearance to combustible 
and  non  combustible  construction  materials  is  0  inches  on  the 
back and sides of the water heater. These water heaters are also 
approved for installation in an alcove.
When the water heater is installed directly on carpeting, the water 
heater  shall  be  installed  on  a  metal  or  wood  panel  extending 
beyond  the  full  width  and  depth  of  the  water  heater  by  at  least 
3 in (76.2 mm) in any direction or, if the water heater is installed 
in  an  alcove  or  closet,  the  entire  floor  shall  be  covered  by  the 
panel.  The  panel  must  be  strong  enough  to  carry  the  weight  of 
the heater when full of water.
NOTE: Adequate  clearance  for  servicing  should  be  maintained 
on all installations. See Service Clearance below.
TO
P VIEW
0
0
0
ALCOVE
FRONT VIEWCLEARANCES TO  COMBUSTIBLE
AND NON COMBUSTIBLE
CONSTRUCTION MA TERIALS
WATER
HEA TER
FRONT
TO
P COVER
FRONT
Figure 7
SERVICE CLEARANCE
A  service  clearance  of  24  inches  (61  cm)  should  be  maintained 
from  serviceable  parts  such  as  the  T&P  valve,  control  system 
components,  gas  valve,  clean  out  opening,  drain  valve,    the  vent 
connection  (exhaust/condensate  elbow)  and  the  condensate 
drain.  Leave  as  much  room  as  possible  above  the  water  heater 
and near the exhaust elbow for this reason.
INTAKE AIR AND VENT PIPE CLEARANCES
The minimum clearance from combustible materials for the vent 
(exhaust) and intake air piping shall be 0 inches. Vent or intake 
air piping passing through a combustible wall or ceiling must be 
a continuous run (no joints).
EXTENDED VENT TERMINATIONS
The water heaters covered by this manual can be installed using 
4 inch pipe for the intake air and/or vent piping up to a maximum 
of 70 equivalent feet (21.3 m). The intake air and/or vent piping 
can be extended up to 120 equivalent feet (36.5 m) by installing 
6 inch pipe. See the Venting Requirements on page 22. 
The  water  heater  ships  from  the  factory  with  two  (2)  4  inch 
terminations  that  are  45°  PVC  elbows  with  a  debris  screen 
installed. When 6 inch intake air or vent pipe is installed, factory 
supplied 6 inch terminations must be used. 
Contact your local distributor or call the parts department phone 
number  listed  on  the  back  cover  of  this  manual  to  order  6  inch 
termination(s).  
						

							12
INSULATION BLANKETS
Do not obstruct water heater air intake
with insulating blanket.
Gas and carbon monoxide detectors
are available.
Install water heater in accordance with
the instruction manual.
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Breathing Hazard - Carbon Monoxide Ga s
Insulation blankets are available to the general public for external 
use  on  gas  water  heaters  but  are  not  necessary  with  these 
products.  The  purpose  of  an  insulation  blanket  is  to  reduce  the 
standby  heat  loss  encountered  with  storage  tank  heaters.  The 
water heaters covered by this manual meet or exceed the Energy 
Policy Act standards with respect to insulation and standby heat 
loss requirements, making an insulation blanket unnecessary.
Should  you  choose  to  apply  an  insulation  blanket  to  this 
heater,  you  should  follow  these  instructions.  See  the  Features 
and  Components  section  of  this  manual  for  identification  of 
components mentioned below. Failure to follow these instructions 
can restrict the air flow required for proper combustion, potentially 
resulting in fire, asphyxiation, serious personal injury or death.
• DO NOT apply insulation to the top of the water heater, as this will 
interfere with safe operation of the blower assembly.
•  DO NOT cover the control system LCD on top of the water heater.
•  DO NOT cover the Temperature-Pressure Relief Valve.
•  DO NOT cover the instruction manual. Keep it on the side of the 
water heater or nearby for future reference.
•  DO obtain new warning and instruction labels from the manufacturer 
for placement on the blanket directly over the existing labels.
•  DO  inspect  the  insulation  blanket  frequently  to  make  certain  it 
does not sag, thereby obstructing combustion air flow.
OPTIONAL DIRECT VENT TERMINATIONS
The water heaters covered by this manual can be installed 
in  a  Direct  Vent  configuration  using  optional  concentric  or 
low profile terminations. 
See  the  Venting  Requirements  on  page  22,  Concentric 
Termination  Installation  on  page  29  and  Low  Profile 
Installation on page 33.
Concentric  and  low  profile  terminations  must  be  ordered 
separately.  Contact  your  local  distributor  or  call  the  parts 
department  phone  number  listed  on  the  back  cover  of  this 
manual to order.
HARD WATER
Where  hard  water  conditions  exist,  water  softening  or  the 
threshold  type  of  water  treatment  is  recommended.  This 
will  protect  the  dishwashers,  coffee  urns,  water  heaters, 
water piping and other equipment.
See  Maintenance  on  page  63  for  sediment  and  lime  scale 
removal procedures.
CIRCULATION PUMPS
A  circulating  pump  is  used  when  a  system  requires  a 
circulating loop or there is a storage tank used in conjunction 
with the water heater. The tank is provided with a 3/4" NPT 
recirculation  loop  return  connection.  Refer  to  Figure  6  for 
its  location.  See  the  Water  Piping  Diagrams  beginning  on 
page 68 for installation location of circulating pumps. 
See  Circulation  Pump  Wiring  Diagrams  on  page  67  for 
electrical hookup information. Install in accordance with the 
current edition of the National Electrical Code, NFPA 70 or 
the Canadian Electrical Code, CSA C22.1.
Stainless  Steel  circulators  are  recommended  for  use  with 
commercial water heaters.
Refer  to  the  circulating  pump  manufacturer’s  instructions 
for its operation, lubrication and maintenance instructions.  
						

							13
If a positive lock-up regulator is required follow these instructions:
1. Positive lock-up gas pressure regulators must be rated at or 
above the input Btu/hr rating of the water heater they supply.
2.  Supply gas regulators shall have inlet and outlet connections 
not less than the minimum supply gas line size for the water 
heater they supply. See Table 13, page 39.
3.  Positive lock-up gas pressure regulator(s) should be installed 
no closer than 3 feet (1 meter) and no farther than 8 feet (2.4 
meters) from the water heater’s inlet gas connection.
4.  After installing the positive lock-up gas pressure regulator(s) 
an  initial  nominal  supply  pressure  setting  of  7.0”  W.C. 
while  the  water  heater  is  operating  is  recommended  and 
will  generally  provide  good  water  heater  operation.  Some 
addition  adjustment  maybe  required  later  to  maintain  a 
steady gas supply pressure.
5.  When  installing  multiple  water  heaters  in  the  same  gas 
supply  system  it  is  recommended  that  individual  positive 
lock-up gas pressure regulators be installed at each unit.
POWER SUPPLY
The  water  heaters  covered  in  this  manual  require  a  120 
VAC,  1Ø  (single  phase),  60Hz,  15  amp  power  supply  and 
must also be electrically grounded in accordance with local 
codes  or,  in  the  absence  of  local  codes,  with  the  National 
Electrical  Code,  ANSI/NFPA  70  or  the  Canadian  Electrical 
Code, CSA C22.1.
DEDICATED POWER WIRING AND BREAKERS
Dedicated  power  supply  wires,  ground  wiring  and  dedicated 
circuit  breakers  often  prevent  electrical  line  noise  and  are 
required when installing the water heater.
POWER FLUCTUATIONS AND ELECTRICAL NOISE
The  water  heater’s  control  system  requires  a  source  of  stable 
clean  electricity  for  proper  operation.  Connecting  the  water 
heater to a branch circuit that is subject to fluctuations in voltage 
level  or  electrical  line  noise  such  as  EMI  (electro  magnetic 
interference)  or  RFI  (radio  frequency  interference)  may  cause 
erratic control system operation and malfunction. 
A  high  quality  power  supply  filter/suppressor  must  be  installed 
if  the  above  conditions  exist.  Call  the  technical  support  phone 
number  listed  on  the  back  cover  of  this  manual  for  more 
information. 
NOTE:  Malfunctions caused by the power supply and the costs 
to  install  power  supply  filters  are  not  covered  under  the  limited 
warranty.
GAS SUPPLY SYSTEMS
Low pressure building gas supply systems are defined as those 
systems  that  cannot  under  any  circumstances  exceed  14” 
W.C.  (1/2  PSI  Gauge).  These  systems  do  not  require  pressure 
regulation.  Measurements  should  be  taken  to  insure  that  gas 
pressures  are  stable  and  fall  within  the  requirements  stated  on 
the  water  heater  rating  plate.  Readings  should  be  taken  with 
all  gas  burning  equipment  off  (static  pressure)  and  with  all  gas 
burning equipment running at maximum rate (dynamic pressure). 
The  gas  supply  pressure  must  be  stable  within  1.5”  W.C.  from 
static  to  dynamic  pressure  to  provide  good  performance. 
Pressure drops that exceed 1.5” W.C. may cause rough starting, 
noisy  combustion  or  nuisance  outages.  Increases  or  spikes  in 
static  pressure  during  off  cycles  may  cause  failure  to  ignite  or 
in  severe  cases  damage  to  appliance  gas  valves.  If  your  low 
pressure  system  does  NOT  meet  these  requirements,  the 
installer is responsible for the corrections.
High  Pressure  building  supply  systems  use  pressures  that 
exceed  14”  W.C.  (1/2  PSI  Gauge).  These  systems  must  use 
field  supplied  regulators  to  lower  the  gas  pressure  to  less  than 
14” W.C. (1/2 PSI Gauge). Water heaters require gas regulators 
that  are  properly  sized  for  the  water  heater  input  and  deliver 
the rating plate specified pressures. Gas supply systems where 
pressure  exceeds  5  PSI  often  require  multiple  regulators  to 
achieve desired pressures. Systems in excess of 5 PSI building 
pressure  should  be  designed  by  gas  delivery  professionals 
for  best  performance.  Water  heaters  connected  to  gas  supply 
systems that exceed 14” W.C. (1/2 PSI Gauge) at any time must 
be equipped with a gas supply regulator.
All models require a minimum gas supply pressure of 4.8" W.C. 
for  natural  gas  and  8.5"  W.C.  for  propane  gas.  The  minimum 
supply  pressure  is  measured  while  gas  is  flowing  (dynamic 
pressure).  The  supply  pressure  should  never  fall  below  4.8" 
W.C. for natural gas and 8.5" W.C. for propane gas. The supply 
pressure  should  be  measured  with  all  gas  fired  appliances 
connected  to  the  common  main  firing  at  full  capacity.  If  the 
supply pressure drops more than 1.5” W.C. as gas begins to flow 
to the water heater then the supply gas system including the gas 
line  and/or  the  gas  regulator  may  be  restricted  or  undersized. 
See  Supply  Gas  Regulator  section  and  Gas  Piping  section  of 
this  manual.  The  gas  valve  on  all  models  has  a  maximum  gas 
supply pressure limit of 14” W.C. The maximum supply pressure 
is measured while gas is not flowing (static pressure).
SUPPLY GAS REGULATOR
The  maximum  allowable  gas  supply  pressure  for  this  water 
heater  is  14.0”  W.  C.  (3.49  kPa)  for  natural  and  propane  gas. 
Install a positive lock-up gas pressure regulator in the gas supply 
line if inlet gas pressure can exceed these pressures at any time.
INSTALLATION REQUIREMENTS  
						

							14
HOT WATER
OUTLET
TO TA NK
INLET
CHECK
VA LVE MIXING
VA LVE
COLD
WA TER
INLET TEMPERED WA
TER
OUTLET
12”  TO 15”
(30-38 cm)
CHECK VA LVE
Figure 8
The National Sanitation Foundation also recommends circulation 
of  180°F  (82°C)  water.  The  circulation  should  be  just  enough 
to  provide  180°F  (82°C)  water  at  the  point  of  take-off  to  the 
dishwashing machine. 
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 67.
NOTE: To comply with NSF Standard 5 installation requirements 
the bottom of the water heater must be sealed to the floor with a 
silicone based sealant or elevated 6 inches above the floor.
CLOSED WATER SYSTEMS
Water  supply  systems  may,  because  of  code  requirements 
or  such  conditions  as  high  line  pressure,  among  others,  have 
installed  devices  such  as  pressure  reducing  valves,  check 
valves, and back flow preventers. Devices such as these cause 
the water system to be a closed system.
THERMAL EXPANSION
As  water  is  heated,  it  expands  (thermal  expansion).  In  a 
closed system the volume of water will grow when it is heated. 
As  the  volume  of  water  grows  there  will  be  a  corresponding 
increase in water pressure due to thermal expansion. Thermal 
expansion  can  cause  premature  tank  failure  (leakage).  This 
type  of  failure  is  not  covered  under  the  limited  warranty. 
Thermal expansion can also cause intermittent Temperature-
Pressure  Relief  Valve  operation:  water  discharged  from  the 
valve  due  to  excessive  pressure  build  up.  This  condition  is 
not  covered  under  the  limited  warranty.  The  Temperature-
Pressure Relief Valve is not intended for the constant relief of 
thermal expansion.
A  properly  sized  thermal  expansion  tank  must  be  installed  on 
all  closed  systems  to  control  the  harmful  effects  of  thermal 
expansion.  Contact  a  local  plumbing  service  agency  to  have  a 
thermal expansion tank installed.
See  Water  Line  Connections  on  page  41  and  the  Water  Piping 
Diagrams beginning on page 68.
MIXING VALVES
Wa ter 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.
Water heated to a temperature which will satisfy clothes washing, 
dish  washing,  and  other  sanitizing  needs  can  scald  and  cause 
permanent  injury  upon  contact.  Short  repeated  heating  cycles 
caused  by  small  hot  water  uses  can  cause  temperatures  at  the 
point of use to exceed the water heater’s temperature setting by 
up to 20°F (11°C).
Some  people  are  more  likely  to  be  permanently  injured  by 
hot  water  than  others.  These  include  the  elderly,  children,  the 
infirm  and  the  physically/mentally  disabled.  Table  6  shows  the 
approximate  time-to-burn  relationship  for  normal  adult  skin. 
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 should be 
installed  at  the  water  heater  (see  Figure  8)  or  at  the  hot  water 
taps to further reduce system water temperature.
Mixing  valves  are  available  at  plumbing  supply  stores.  Consult 
a  Qualified  Installer  or  Service  Agency.  Follow  mixing  valve 
manufacturer’s instructions for installation of the valves.
TABLE 6 
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)
DISHWASHING MACHINES
All  dishwashing  machines  meeting  the  National  Sanitation 
Foundation  requirements  are  designed  to  operate  with  water 
flow pressures between 15 and 25 pounds per square inch (103 
kPa and 173 kPa). Flow pressures above 25 pounds per square 
inch (173 kPa), or below 15 pounds per square inch (103 kPa), 
will result in improperly sanitized dishes. Where pressures are 
high, a water pressure reducing or flow regulating control valve 
should  be  used  in  the  180°F  (82°C)  line  to  the  dishwashing 
machine  and  should  be  adjusted  to  deliver  water  pressure 
between these limits.  
						

							15
Water Damage Hazard
Temperature-Pressure Relief V alve discharge
pipe must terminate at adequate drain.
CAUTION
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.
Burn hazard.
Hot water discharge. Keep clear of  Temperature-
Pressure Relief V alve
discharge outlet.
The  Temperature-Pressure  Relief  Valve  must  be  manually 
operated  at  least  twice  a  year.  Caution  should  be  taken  to 
ensure  that  (1)  no  one  is  in  front  of  or  around  the  outlet  of  the 
Temperature-Pressure  Relief  Valve  discharge  line,  and  (2)  the 
water  manually  discharged  will  not  cause  any  bodily  injury  or 
property  damage  because  the  water  may  be  extremely  hot.  If 
after  manually  operating  the  valve,  it  fails  to  completely  reset 
and continues to release water, immediately close the cold water 
inlet  to  the  water  heater,  follow  the  draining  instructions  in  this 
manual, and replace the Temperature-Pressure Relief Valve with 
a properly rated/sized new one.
NOTE:  The  purpose  of  a  Temperature-Pressure  Relief  Valve 
is  to  prevent  excessive  temperatures  and  pressures  in  the 
storage  tank. The T&P  valve  is  not  intended  for  the  constant 
relief of thermal expansion. A properly sized thermal expansion 
tank must be installed on all closed systems to control thermal 
expansion, see Closed Water Systems and Thermal Expansion   
on page 14.
If you do not understand these instructions or have any questions 
regarding the Temperature-Pressure Relief Valve call the toll free 
number  listed  on  the  back  cover  of  this  manual  for  technical 
assistance.
TEMPERATURE-PRESSURE RELIEF VALVE
Explosion Hazard
Te mperature-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.
This  water  heater  is  provided  with  a  properly  rated/sized  and 
certified  combination  Temperature-Pressure  Relief  Valve  (T&P 
valve) by the manufacturer. The valve is certified by a nationally 
recognized  testing  laboratory  that  maintains  periodic  inspection 
of  production  of  listed  equipment  of  materials  as  meeting  the 
requirements  for  Relief  Valves  for  Hot  Water  Supply  Systems, 
ANSI Z21.22 • CSA 4.4, and the code requirements of ASME.
If  replaced,  the  new  T&P  valve  must  meet  the  requirements 
of  local  codes,  but  not  less  than  a  combination  Temperature-
Pressure  Relief  Valve  rated/sized  and  certified  as  indicated  in 
the  above  paragraph.  The  new  valve  must  be  marked  with  a 
maximum  set  pressure  not  to  exceed  the  marked  hydrostatic 
working pressure of the water heater (150 psi = 1,035 kPa) and 
a discharge capacity not less than the water heater Btu/hr or kW 
input rate as shown on the water heater’s model rating label.
NOTE: In addition to the factory installed Temperature-Pressure 
Relief 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 technical assistance in sizing a Temperature-Pressure Relief 
Valve for remote storage tanks.
For safe operation of the water heater, the Temperature-Pressure 
Relief  Valve  must  not  be  removed  from  its  designated  opening 
nor  plugged.  The  Temperature-Pressure  Relief  Valve  must  be 
installed directly into the fitting of the water heater designed for the 
relief valve. Install discharge piping so that any discharge will exit 
the pipe within 6 inches (15.2 cm) above an adequate floor drain, 
or  external  to  the  building.  In  cold  climates  it  is  recommended 
that it be terminated at an adequate drain inside the building. Be 
certain that no contact is made with any live electrical part. The 
discharge opening must not be blocked or reduced in size under 
any  circumstances.  Excessive  length,  over  30  feet  (9.14  m),  or 
use  of  more  than  four  elbows  can  cause  restriction  and  reduce 
the discharge capacity of the valve.
No  valve  or  other  obstruction  is  to  be  placed  between  the 
Temperature-Pressure Relief Valve and the tank. 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.  
						

							16
CONDENSATE DRAIN
The  water  heaters  covered  in  this  manual  are  condensing 
appliances and require a building drain to be located in close 
proximity to allow the condensate to drain safely. 
Condensate  drains  from  the  water  heater  at  the  exhaust/
condensate  elbow  located  at  the  bottom.  The  field  installed 
condensate  drain  line  must  not  be  elevated  above  the 
condensate  drain  connection  on  the  exhaust/condensate 
elbow, see Figure 9.  If the condensate does not drain properly 
it will build up in the exhaust (vent) elbow. This will restrict the 
flow  of  flue  gases  and  cause  the  Blocked  Exhaust  pressure 
switch  to  open  its  contacts.  The  control  system  monitors  all 
pressure  switches,  if  the  Blocked  Exhaust  Switch  contacts 
are open the control system will lock out and disable heating 
operation.  The  “Blocked  Exhaust”  Fault  message  will  be 
displayed  on  the  control  system’s  LCD,  see  Fault  And  Alert 
Conditions beginning on page 59.
The Condensate Cleanout Cap must be on and tight when unit 
is in operation.
The  exhaust  elbow  has  a  built  in  condensate  trap.  Do  not 
install  an  additional  trap  in  the  condensate  drain  piping.  See 
Figure 9.
NOTE: If  the  “Blocked  Exhaust  “  Fault  message  is  ever 
displayed  on  the  control  system  LCD,  check  the  condensate 
drain first and ensure it is not blocked.
EXHAUST  (VENT)
ELBOW THIS SIDE VIEW 
OF EXHAUST  
ELBOW  AND 
ARROW INDICA TE 
THE LOCA TION OF 
THE PRESSURE  PORT
BUILDING
DRAIN
CONDENSA
TE
CLEANOUT  CAP
CONDENSA TE DRAIN
LINE - FIELD INST ALLED
CONDENSATE
DRAIN LINE 
CONNECTION
DRAIN LINE TO TERMINAT E NO
MORE  THAN 6 INCHES  (15.2cm)
ABOVE DRAIN
Figure 9
CONDENSATE DRAIN WATER TRAP
Do  not  remove  the  factory  installed  exhaust/condensate 
elbow  for  any  reason,  see  Figure  9.  The  water  heater’s 
vent  pipe  is  under  a  slight  positive  pressure  while  unit  is  in 
operation. The water trap prevents flue gases from escaping 
into  the  installed  space.  The  exhaust  elbow  has  a  "built  in" 
condensate  trap.  Do  not  install  an  additional  trap  in  the 
condensate  drain  piping.  See  Figure  9.  See  Condensate 
Drain Installation on page 38.
CONDENSATE PH LEVEL
The condensate drains from the water heater’s covered in 
this manual have PH levels between 4.3 and 5.0. Install a 
commercially  available  neutralizing  kit  if  required  by  local 
codes.
NOTE: Lower PH levels are acidic. Do not connect a metal 
drain  line,  such  as  copper,  to  the  water  heater  for  this 
reason. See Condensate Drain Installation on page 38.
COMBUSTIBLE MATERIAL STORAGE
Fire or Explosion Hazar d
Read instruction manual befor e
installing, using or servicing water heater .
Avoid all ignition sources if you smell gas .
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
Use only the gas shown on the water heater rating label.
Keep ignition sources away from faucets after extended
periods of non-use. Maintain required clearances to combustibles. Do not expose water heater controls to excessive gas
pressure.
Keep  appliance  area  clear  and  free  of  combustible  materials, 
gasoline and other flammable vapors and liquids.
CONTAMINATED AIR
Breathing Hazard - Carbon Monoxide Ga
s
Install water heater in accordance with
the Instruction Manual and NFPA 54 or
CAN/CSA-B149.1.
To  avoid injur y, combustion and ventilation
air must be taken from outdoors.
Do not place chemical vapor  emitting
products near water heater .
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Corrosion  of  the  flue  ways  and  vent  system  may  occur  if  air  for 
combustion  contains  certain  chemical  vapors.  Such  corrosion 
may result in failure and risk of asphyxiation.
Combustion  air  that  is  contaminated  can  greatly  diminish  the 
life  span  of  the  water  heater  and  water  heater  components 
such as hot surface igniters and burners. Propellants of aerosol 
sprays,  beauty  shop  supplies,  water  softener  chemicals  and 
chemicals used in dry cleaning processes that are present in the 
combustion, ventilation or ambient air can cause such damage.
Do not store products of this sort near the water heater. Air which 
is brought in contact with the water heater should not contain any 
of  these  chemicals.  If  necessary,  uncontaminated  air  should  be 
obtained  from  remote  or  outdoor  sources. The  limited  warranty  is 
voided when failure of water heater is due to a corrosive atmosphere. 
(See limited warranty for complete terms and conditions).
If  the  water  heater  will  be  used  in  beauty  shops,  barber  shops, 
cleaning  establishments,  or  self-service  laundries  with  dry 
cleaning  equipment,  it  is  imperative  that  the  water  heater(s)  be 
installed in a Direct Vent configuration so that all air for combustion 
is derived directly from the outdoor atmosphere through a sealed 
intake air pipe. See Venting Installation on page 21.  
						

							17
UNUSUALLY TIGHT CONSTRUCTION
In  unconfined  spaces  in  buildings,  infiltration  may  be  adequate 
to  provide  air  for  combustion,  ventilation  and  dilution  of  flue 
gases.  However,  in  buildings  of  unusually  tight  construction  (for 
example,  weather  stripping,  heavily  insulated,  caulked,  vapor 
barrier,  etc.)  additional  air  must  be  provided  using  the  methods 
described in the Confined Space section that follows.
CONFINED SPACE
A Confined Space is one whose volume IS LESS THAN 50 cubic 
feet per 1,000 Btu/hr (4.8 cm per kW) of the total input rating of 
all appliances installed in the space.
Openings  must  be  installed  to  provide  fresh  air  for  combustion, 
ventilation and dilution in confined spaces. The required size for 
the openings is dependent on the method used to provide fresh 
air  to  the  confined  space  AND  the  total  Btu/hr  input  rating  of  all 
appliances installed in the space.
DIRECT VENT APPLIANCES
Appliances installed in a Direct Vent configuration that derive all 
air for combustion from the outdoor atmosphere through sealed 
intake air piping are not factored in the total appliance input Btu/
hr calculations used to determine the size of openings providing 
fresh air into confined spaces.
EXHAUST FANS
Where exhaust fans are installed, additional air shall be provided 
to  replace  the  exhausted  air.  When  an  exhaust  fan  is  installed 
in  the  same  space  with  a  water  heater,  sufficient  openings  to 
provide  fresh  air  must  be  provided  that  accommodate  the 
requirements for all appliances in the room and the exhaust fan. 
Undersized  openings  will  cause  air  to  be  drawn  into  the  room 
through the water heater’s vent system causing poor combustion. 
Sooting, serious damage to the water heater and the risk of fire 
or explosion may result. It can also create a risk of asphyxiation.
LOUVERS AND GRILLES
The  free  areas  of  the  fresh  air  openings  in  the  instructions  that 
follow do not take in to account the presence of louvers, grilles or 
screens in the openings.
The  required  size  of  openings  for  combustion,  ventilation  and 
dilution air shall be based on the “net free area” of each opening. 
Where the free area through a design of louver or grille or screen 
is  known,  it  shall  be  used  in  calculating  the  size  of  the  opening 
required to provide the free area specified. Where the louver and 
grille  design  and  free  area  are  not  known,  it  shall  be  assumed 
that wood louvers will have 25% free area and metal louvers and 
grilles will have 75% free area. Non motorized louvers and grilles 
shall be fixed in the open position.
AIR REQUIREMENTS
Breathing Hazard - Carbon Monoxide Ga s
Install water heater in accordance with
the Instruction Manual and NFPA 54 or
CAN/CSA-B149.1.
To  avoid injur y, combustion and ventilation
air must be taken from outdoors.
Do not place chemical vapor  emitting
products near water heater .
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
For safe operation an adequate supply of fresh uncontaminated 
air for combustion and ventilation must be provided.
An insufficient supply of air can cause recirculation of combustion 
products  resulting  in  contamination  that  may  be  hazardous  to 
life. Such a condition often will result in a yellow, luminous burner 
flame, causing sooting of the combustion chamber, burners and 
flue tubes and creates a risk of asphyxiation.
Do  not  install  the  water  heater  in  a  confined  space  unless  an 
adequate supply of air for combustion and ventilation is brought 
in  to  that  space  using  the  methods  described  in  the  Confined 
Space section that follows. 
Never obstruct the flow of ventilation air. If you have any doubts 
or  questions  at  all,  call  your  gas  supplier.  Failure  to  provide  the 
proper amount of combustion air can result in a fire or explosion 
and cause property damage, serious bodily injury or death.
UNCONFINED SPACE
An Unconfined Space is one whose volume  IS NOT LESS  THAN 
50  cubic  feet  per  1,000  Btu/hr  (4.8  cubic  meters  per  kW)  of  the 
total input rating of all appliances installed in the space. Rooms 
communicating  directly  with  the  space,  in  which  the  appliances 
are  installed,  through  openings  not  furnished  with  doors,  are 
considered a part of the unconfined space.
Makeup  air  requirements  for  the  operation  of  exhaust  fans, 
kitchen  ventilation  systems,  clothes  dryers  and  fireplaces  shall 
also  be  considered  in  determining  the  adequacy  of  a  space  to 
provide combustion, ventilation and dilution air.  
						

							18
Alternatively a single permanent opening, commencing within 12 
inches  (300  mm)  of  the  top  of  the  enclosure,  shall  be  provided. 
See  Figure  11.  The  water  heater  shall  have  clearances  of  at 
least 1 inch (25 mm) from the sides and back and 6 inches (l50 
mm) from the front of the water heater. The opening shall directly 
communicate with the outdoors or shall communicate through a 
vertical  or  horizontal  duct  to  the  outdoors  or  spaces  that  freely 
communicate  with  the  outdoors  and  shall  have  a  minimum  free 
area of the following:
1. 1 square inch per 3000 Btu/hr (700 mm2 per kW) of the total 
input rating of all appliances located in the enclosure, and
2.  Not  less  than  the  sum  of  the  areas  of  all  vent  connectors  in 
the space.
OUTDOOR AIR THROUGH TWO HORIZONTAL DUCTS
Figure 12
The  confined  space  shall  be  provided  with  two  permanent 
horizontal ducts, one commencing within 12 inches (300 mm) of 
the  top  and  one  commencing  within  12  inches  (300  mm)  of  the 
bottom of the enclosure. The horizontal ducts shall communicate 
directly with the outdoors. See Figure 12.
Each duct opening shall have a minimum free area of 1 square 
inch per 2,000 Btu/hr (1100 mm2 per kW) of the aggregate input 
rating of all appliances installed in the enclosure.
When ducts are used, they shall be of the same cross sectional 
area  as  the  free  area  of  the  openings  to  which  they  connect. 
The minimum dimension of rectangular air ducts shall be not less 
than 3 inches. 
FRESH AIR OPENINGS FOR CONFINED SPACES
The  following  instructions  shall  be  used  to  calculate  the  size, 
number  and  placement  of  openings  providing  fresh  air  for 
combustion,  ventilation  and  dilution  in  confined  spaces.  The 
illustrations shown in this section of the manual are a reference 
for  the  openings  that  provide  fresh  air  into  confined  spaces 
only.  DO NOT refer to these illustrations for the purpose of vent 
installation.  See  Venting  Installation  on  page  21  for  complete 
venting installation instructions.
OUTDOOR AIR THROUGH TWO OPENINGS
Figure 10
The  confined  space  shall  be  provided  with  two  permanent 
openings, one commencing within 12 inches (300 mm) of the top 
and one commencing within 12 inches (300 mm) of the bottom of 
the enclosure. The openings shall communicate directly with the 
outdoors. See Figure 10.
Each  opening  shall  have  a  minimum  free  area  of  1  square  inch 
per 4,000 Btu/hr (550 mm2 per kW) of the aggregate input rating 
of  all  appliances  installed  in  the  enclosure.  Each  opening  shall 
not be less than 100 square inches (645 cm2). 
OUTDOOR AIR THROUGH ONE OPENING
Figure 11  
						

							19
AIR FROM OTHER INDOOR SPACES
Figure 14
The  confined  space  shall  be  provided  with  two  permanent 
openings, one commencing within 12 inches (300 mm) of the top 
and one commencing within 12 inches (300 mm) of the bottom of 
the enclosure. See Figure 14.
Each  opening  shall  communicate  directly  with  an  additional 
room(s)  of  sufficient  volume  so  that  the  combined  volume  of  all 
spaces meets the criteria for an Unconfined Space.
Each  opening  shall  have  a  minimum  free  area  of  1  square  inch 
per  1,000  Btu/hr  (1100  mm2  per  kW)  of  the  aggregate  input 
rating of all appliances installed in the enclosure. Each opening 
shall not be less than 100 square inches (645 cm2). 
OUTDOOR AIR THROUGH TWO VERTICAL DUCTS
The  illustrations  shown  in  this  section  of  the  manual  are  a 
reference  for  the  openings  that  provide  fresh  air  into  confined 
spaces only.
DO NOT  refer  to  these  illustrations  for  the  purpose  of  vent 
installation.  See  Venting  Installation  on  page  21  for  complete 
venting installation instructions.
Figure 13
The confined space shall be provided with two permanent vertical 
ducts, one commencing within 12 inches (300 mm) of the top and 
one commencing within 12 inches (300 mm) of the bottom of the 
enclosure. The vertical ducts shall communicate directly with the 
outdoors. See Figure 13.
Each duct opening shall have a minimum free area of 1 square 
inch per 4,000 Btu/hr (550 mm2 per kW) of the aggregate input 
rating of all appliances installed in the enclosure. 
When ducts are used, they shall be of the same cross sectional 
area  as  the  free  area  of  the  openings  to  which  they  connect. 
The minimum dimension of rectangular air ducts shall be not less 
than 3 inches.  
						

							20
COMMONWEALTH OF MASSACHUSETTS
For all side wall terminated, horizontally vented power vent, direct 
vent, and power direct vent gas fueled water heaters installed in 
every  dwelling,  building  or  structure  used  in  whole  or  in  part  for 
residential  purposes,  including  those  owned  or  operated  by  the 
Commonwealth and where the side wall exhaust vent termination 
is  less  than  seven  (7)  feet  above  finished  grade  in  the  area  of 
the  venting,  including  but  not  limited  to  decks  and  porches,  the 
following requirements shall be satisfied:
INSTALLATION OF CARBON MONOXIDE DETECTORS
At  the  time  of  installation  of  the  side  wall  horizontal  vented 
gas  fueled  equipment,  the  installing  plumber  or  gasfitter  shall 
observe  that  a  hard  wired  carbon  monoxide  detector  with  an 
alarm  and  battery  back-up  is  installed  on  the  floor  level  where 
the  gas  equipment  is  to  be  installed.  In  addition,  the  installing 
plumber  or  gasfitter  shall  observe  that  a  battery  operated  or 
hard wired carbon monoxide detector with an alarm is installed 
on  each  additional  level  of  the  dwelling,  building  or  structure 
served by the sidewall horizontal vented gas fueled equipment. 
It shall be the responsibility of the property owner to secure the 
services of qualified licensed professionals for the installation of 
hard wired carbon monoxide detectors.
In  the  event  that  the  side  wall  horizontally  vented  gas  fueled 
equipment is installed in a crawl space or an attic, the hard wired 
carbon  monoxide  detector  with  alarm  and  battery  back-up  may 
be installed on the next adjacent floor level.
In the event that the requirements of this subdivision can not be 
met at the time of completion of installation, the owner shall have 
a period of thirty (30) days to comply with the above requirements 
provided that during said thirty (30) day period, a battery operated 
carbon monoxide detector with an alarm shall be installed.
APPROVED CARBON MONOXIDE DETECTORS
Each carbon monoxide detector as required in accordance with 
the above provisions shall comply with NFPA 720 and be ANSI/
UL 2034 listed and CSA certified.
SIGNAGE
A  metal  or  plastic  identification  plate  shall  be  permanently 
mounted  to  the  exterior  of  the  building  at  a  minimum  height  of 
eight  (8)  feet  above  grade  directly  in  line  with  the  exhaust  vent 
terminal for the horizontally vented gas fueled heating appliance 
or equipment. The sign shall read, in print size no less than one-
half  (1/2)  inch  in  size, “GAS VENT DIRECTLY BELOW. KEEP 
CLEAR OF ALL OBSTRUCTIONS.”
INSTALLATION REQUIREMENTS - COMMONWEALTH OF MASSACHUSETTS
INSPECTION
The  state  or  local  gas  inspector  of  the  side  wall  horizontally 
vented  gas  fueled  equipment  shall  not  approve  the  installation 
unless,  upon  inspection,  the  inspector  observes  carbon 
monoxide detectors and signage installed in accordance with the 
provisions of 248 CMR 5.08(2)(a) 1 through 4.
EXEMPTIONS
The  following  equipment  is  exempt  from  248  CMR  5.08(2)(a)1 
through 4:
1.  The equipment listed in Chapter 10 entitled “Equipment Not 
Required To Be Vented” in the most current edition of NFPA 
54 as adopted by the Board; and
2.  Product  Approved  side  wall  horizontally  vented  gas  fueled 
equipment installed in a room or structure separate from the 
dwelling,  building,  or  structure  used  in  whole  or  in  part  for 
residential purposes.
MANUFACTURER REQUIREMENTS - GAS 
EQUIPMENT VENTING SYSTEM PROVIDED
When  the  manufacturer  of  Product  Approved  side  wall 
horizontally  vented  gas  equipment  provides  a  venting  system 
design  or  venting  system  components  with  the  equipment,  the 
instructions  provided  by  the  manufacturer  for  installation  of  the 
equipment and the venting system shall include:
1. Detailed instructions for the installation of the venting system 
design or the venting system components; and
2.  A complete parts list for the venting system design or venting 
system.
MANUFACTURER REQUIREMENTS - GAS 
EQUIPMENT VENTING SYSTEM NOT PROVIDED
When  the  manufacturer  of  a  Product  Approved  side  wall 
horizontally  vented  gas  fueled  equipment  does  not  provide  the 
parts  for  venting  the  flue  gases,  but  identifies  “special  venting 
systems,”  the  following  requirements  shall  be  satisfied  by  the 
manufacturer:
1. The  referenced  “special  venting  system”  instructions  shall 
be  included  with  the  appliance  or  equipment  installation  
 instructions; and 
2.  The “special venting systems” shall be Product Approved by 
the Board, and the instructions for that system shall include a 
parts list and detailed installation instructions. 
A  copy  of  all  installation  instructions  for  all  Product  Approved 
side  wall  horizontally  vented  gas  fueled  equipment,  all  venting 
instructions,  all  parts  lists  for  venting  instructions,  and/or  all 
venting  design  instructions  shall  remain  with  the  appliance  or   
equipment at the completion of the installation.