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PART 4. VENTING
1) Never vent into a walkway, patio area, alley or otherwise public area less than 7' from the ground. (See detail
below references Fig. A.12.9 in the National Fuel Gas Code 2009 “Exit Terminals of Mechanical Draft and Direct-
Venting Systems;” see Figure 4-1, pg.21)
2) Never vent over or under a window or a doorway where the exhaust plume or condensation liquid will cause
obtrusive or dangerous conditions. (Refer to National Fuel Gas Code, CAN B149).
3) Never install a heat saver or similar product to capture waste heat from exhaust.
4) Always have a vent location at least 12" above maximum snow level.
5) Always have vent a minimum of 24" above ground level, away from shrubs and bushes.
6) Follow local gas codes in your region or refer to National Fuel Gas Code, Can B149.
7) Always have at least 36" distance from an inside corner of the outside walls.
8) Maintain at least 48" clearance to electric, gas meters, windows, exhaust fans, chimneys, inlets or mechanical vents.
9)
VERY IMPORTANT!
The inlet air connection must be connected to outside air and should be located no closer
than 8" and no further than 24" to the exhaust.
10) Always place screens in all openings in intake and exhaust to prevent foreign matter from entering the EVO.
11) The vent intake and exhaust must be properly cleaned and glued if plastic, and sealed per the manufacturer’s
directions if stainless for a pressure tight joint. Several methods for venting the EVO can be found in Figures 4-2
through 4-6 of this section. Use these layouts as guidelines: certain site conditions such as multiple roof lines/
pitches may require venting modifications (consult Hamilton Engineering Company, Inc.).
B. VENTING THE EVO (continued)
The following are code restrictions for the location of the flue gas vent terminal.
Compliance to these requirements doesn’t insure a satisfactory installation; good common
sense must also be applied. It is important to make sure that exhaust gases are not
recirculated into the inlet air of the EVO. If there is any doubt, contact the factory BEFORE
installing.
NOTICE
Exhaust piping should be sloped
back to the connection on the EVO,
at least 1/4” per foot to remove
additional condensate that forms
within the pipe. The total combined
length of pipe (intake piping plus
exhaust piping added together)
including elbow allowances intake
and exhaust should not exceed the
length shown in the vent table. The
minimum combined vent length
should not be less than a combined
length of 6’ plus two 90° elbows.
Choose your vent termination
locations carefully. You must also
make certain that exhaust gas does
not re-circulate back into the intake
pipe. You must place them in an
open area and follow the following
guidelines:
