Lincoln SCR Manual
18
b.
With
Outside Air Connected to the unit. In this manner the appliance is a Direct Vent
Appliance (sealed Combustion System) as listed in NFPA 211-6.
3.3.3.2 Direct Vent Appliance (Sealed Combustion System Appliance) A system
consisting of an appliance, combustion air and flue gas connections between the
appliance and the outside atmosphere, and a vent cap supplied by the manufacturer, and
constructed so that all the air for combustion is obtained from the outside atmosphere
and all flue gases are discharged to the outside atmosphere.
Special Venting Arrangements are listed in NFPA 211-31
10.7.1.2 The Vent Terminal of a Direct Vent Appliance with an input of 10000 BTU/Hr or
less shall be located at least 6” from any opening into a building, and such an appliance
with an input of over 10000 BTU/Hr, but not over 50000 BTU/Hr shall not be located
less than 9” from any opening through which vent gases could enter a building, and the
vent terminal of such appliance with an input over 50000 BTU/Hr shall be located not
less than 12” from the opening.
Figure 4b
1’ (305 mm) ABOVE, BELOW OR HORIZONTALLY FROM a door, window, cavity, or air
vent.