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VENTING
Page 16 of 50
NOTICE
The following are code restrictions for the location of the ue 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.
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:
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.17)
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 and 4-3 of this section, on page 18. Use these layouts as guidelines: certain
site conditions such as multiple roof lines/pitches may require venting modications (consult Hamilton
Engineering, Inc.).
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