AERCO KC1000 Low NOx Water Heater July 2011 - Manual (Page 17)

INSTALLATION
2-9
2.7 FLUE GAS VENT INSTALLATION
AERCO Gas Fired Venting and Combustion Air
Guide, GF-1050, must be consulted before any
flue or combustion air venting is designed or
installed. Suitable, U/L approved, positive pres-
sure, watertight vent materials MUST be used
for safety and UL certification. Because the unit
is capable of discharging low temperature
exhaust gases, the flue must be pitched back
towards the unit a minimum of 1/4" per foot to
avoid any condensate pooling and to allow for
proper drainage.
While there is a positive flue pressure during
operation, the combined pressure drop of vent
and combustion air systems must not exceed
140 equivalent feet of 0.81” W.C. Fittings as
well as pipe lengths must be calculated as part
of the equivalent length. For a natural draft
installation the draft must not exceed - 0.25”
W.C. These factors must be planned into the
vent installation. If the maximum allowable
equivalent lengths of piping are exceeded, the
unit will not operate properly or reliably.
For Massachusetts installations, the Heatfab
Division of the Selkirk Corporation provides vent
systems which conform to all applicable
requirements for installations within the
Commonwealth of Massachusetts. Contact
information for this supplier is as follows:
Selkirk Corporation
Heatfab Division
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: 1-800-772-0739
www.heat-fab.com
2.8 COMBUSTION AIR
The AERCO Gas-Fired Heater Venting and
Combustion Air Guide, GF-1050 MUST be
consulted before any flue or inlet air venting is
designed or installed. Air supply is a direct
requirement of ANSI 223.1, NFPA-54, CSA
B149.1 and local codes. These codes should be
consulted before a permanent design is
determined.
The combustion air must be free of chlorine,
halogenated hydrocarbons or other chemicals
that can become hazardous when used in gas-
fired equipment. Common sources of these
compounds are swimming pools, degreasing
compounds, plastic processing, and refrigerants.
Whenever the environment contains these types
of chemicals, combustion air MUST be supplied
from a clean area outdoors for the protection
and longevity of the equipment and warranty
validation.
The more common methods of combustion air
supply are outlined in the following paragraphs.
For combustion air supply from ducting, consult
the AERCO GF-1050, Gas Fired Venting and
Combustion Air Guide.
2.8.1 COMBUSTION AIR FROM OUTSIDE
THE BUILDING
Air supplied from outside the building must be
provided through two permanent openings. For
each unit these two openings must have a free
area of not less than one square inch for each
4000 BTUs input of the equipment or 250
square inches of free area. The free area must
take into account restrictions such as louvers
and bird screens. For Canada installations, refer
to the requirements specified in CSA B149.1-10,
8.4.1 and 8.4.3.
2.8.2 COMBUSTION AIR FROM INSIDE
THE BUILDING
When combustion air is provided from within the
building, it must be supplied through two
permanent openings in an interior wall. Each
opening must have a free area of not less than
one square inch per 1000 BTUH of total input or
1000 square inches of free area. The free area
must take into account any restrictions, such as
louvers.
NOTE
KC1000 units equipped with Low NOx
Burners require an optional Cold Air
Damper for operation with Direct
Vent/Sealed Combustion. The Cold Air
Damper is also required when the unit is
installed in an area where the combustion
air supply temperature can drop below
55°F. Refer to the following paragraph
(2.8.3) and GF-1050 for installation details
2.8.3 SEALED COMBUSTION
The KC Heater is UL approved for 100% sealed
combustion application when installed properly.
When a sealed combustion air application is
installed, the sealed combustion air piping must
be deducted from the maximum allowable
discharge piping amounts. Each unit must have
a minimum 6" diameter connection made to the
special Inlet Air Adapter # GP-18917 available
from AERCO. This adapter bolts directly on to
the air inlet of the unit’s blower. See installation
instructions with adapter. All inlet air ducts must
be sealed air tight.