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...

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...

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...

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....

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...

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...

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...

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...

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...

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...