26 | Installation instructions
This is a high efficiency appliance,
condensate flow can be as much as
2.1 gal/hr at full power.
4.6.6 Single Pipe Venting
▶ Installations resulting in negative
pressure/back draft require sealed
combustion (twin pipe / concentric).
▶ Damage caused from back draft, ie.
freezing, are not covered by warranty.
▶ When installed in an environment where
corrosive chemicals or dirty air (e.g. hair
salons, car washes) are present the
sealed combustion (twin pipe or
concentric) is required.
Although it is permissible to draw the air-intake from the inside,
it is not the manufacturer's recommended installation method.
Install a 90° elbow or air intake screen on the top of the air-
intake inlet adaptor to prevent foreign objects from falling into
If a single pipe installation is utilized, follow guidelines below
for providing adequate combustion air for the water heater as
well as any other appliances that may consume air in the same
space. Always follow local codes and regulations of the
authority having jurisdiction.
Appliances located in unconfined spaces:
– a) An unconfined space is one whose volume is greater
than 50 cubic feet (1.42 cubic meter) per 1000 BTU/
hr (292.81 Watts) of the combined rating of all
appliances installed in the space. That would be 9950
cubic feet (281.8 cubic meters) or 1243 square feet
with 8 foot ceiling, for a single 199 kBTU water heater.
– b) In unconfined spaces in buildings of conventional
frame, masonry, or metal construction, infiltration air is
normally adequate to provide air for combustion.
Appliances located in confined spaces:
The confined space must be provided with two permanent
openings, one commencing within 12 inches (304.8mm)
of the top and one commencing within 12 inches
(304.8mm) of the bottom of the enclosure. Each opening
must have a minimum free area of one square inch per:
– 1000 BTU/hr (292.81 Watts) if all air is taken from
inside the building
6 720 816 815 (2016/10)
– 2000 BTU/hr (585.62 Watts) if all air is taken from the
outside by horizontal ducts
– 4000 BTU/hr (1171.24 Watts)if all air is taken from
the outside by direct openings or vertical ducts
Or the confined space must be provided with one permanent
opening or duct that is within 12 inches (304.8mm) of the
ceiling of the enclosure. This opening must have a minimum
free area of one square inch per:
– 3000 BTU/hr (878.43 Watts) if all air is taken from the
outside by a direct opening or vertical duct.
Louvers, grills and screens have a blocking effect, when used,
increase the sizes of your openings by 300% for wood louvers
(as wood type will reduce the free air by 75%) and 43% for
metal louvers (as metal will reduce the free air by 30%). Refer
to the National Fuel Gas Code for complete information.
Greentherm 9800 SE 160/199 | SEC 199