Specifications

Armstrong International
IOM-706
Flo-Direct Water Heater
Page 16 of 45
Installing Intake Air Ducting
Installing Intake Air Ducting
Using outside air is recommended, especially:
• When inside air is not dust free
• When inside air is under positive or negative pressure
Alternatively, filtration may be used.
Duct diameter must be at least
as large as intake diameter on
blower. 15% diameter increase
is recommended every 10 feet
removed from heater.
Material can be:
• CPVC
• Galvanized sheet metal
• Single wall stainless steel
Note:
Do not use manifold connected to other appliances.
Do not run heater under negative air pressure.
Typical enclosure in
sheet metal box with
screen.
Provide
independent
support for duct.
Do not rest weight
on heater.
Roof
Wall
Top must be solid metal.
Bird screen
required.