Series-LA/LX/LXR
Page 20
6/15/2010
Venting / Combustion Air Ducting
General Requirements
•
Refer to the
National Fuel Gas Code,
ANSI Z223.1 (NFPA 54) in the US and CAN/CGA B149.1
and B149.2
Installation Codes
in Canada, as well as all local requirements for general venting
guidance.
•
Series LA/LX/LXR Infrared Heaters may be installed vented or unvented.
•
Series LA/LX/LXR Infrared Heaters may be vented horizontally or vertically using conventional
venting materials.
•
If heater is to be vented horizontally, the vent from building must:
o
Be not less than seven feet above grade when located adjacent to public walkways.
o
Terminate at least three feet above any forced air inlet located within ten feet.
o
Terminate at least four feet below, four feet horizontally from or one foot above any door,
window, or gravity inlet into any building.
o
Be located at least 12" inches from any opening through which vent gases could enter a
building.
o
Be beyond any combustible overhang.
o
Be installed at a height sufficient to prevent blockage by snow.
•
Optional outside air supply may be directed to the heater horizontally or vertically.
Important
Maximum total vent length allowed for any model heater is 30'
feet.
Maximum total fresh air inlet duct length allowed for any
model heater is 30
'
feet.
Total of vent length plus outside air supply duct length cannot
exceed 50
'
feet for any heater with maximum heat exchanger
length.
If condensation outside the vent pipe duct is a problem, then
make provisions for removal or containment.
Note:
The above stated requirements assume a maximum of 2
elbows in the total combination of vent and air supply duct.
Subtract 5
'
feet of allowable length for each elbow if 3 or more
elbows are used. Do not use flexible duct for fresh air supply
duct.
Un-Vented Operation
•
In general, where heaters are installed without direct outside combustion air, fresh air ventilation
must be provided to the building space (4 cfm per 1000 BTU/Hr in USA, 3 cfm per 1000 BTU/Hr
in Canada). Verify applicable codes.
•
Optional outside air supply is not recommended for unvented heaters due to possible pressure
imbalances in the building space.
•
Ensure that minimum combustible clearances are maintained for unvented heaters. Refer to Table
2, for required clearance dimensions.
