Specifications

Armstrong International
IOM-706
Flo-Direct Water Heater
Page 15 of 45
Installing Exhaust Ducting
Installing Exhaust Ducting
Note:
• Roof installation preferred.
• Flo-Direct heater is not naturally drafting;
exhaust is under slight pressure.
• Insulation is not required because exhaust
temperature is only a few degrees above
incoming water temperature.
Install horizontal exhaust
duct sloping upward to drain
condensate in duct (1/4" per
foot is recommended).
Condensate will
drip from end of
horizontal ducting.
Install where dripping
will not be a nuisance
or ice a hazard.
Connect exhaust
ducting using either
CPVC or single wall,
welded stainless steel.
Snap-together ducting
is not recommended.
Cover external
termination with rain
guard and bird screen.
Models AFD-1000 and
AFD-1500 require a rubber
sewer connection boot to
connect. All other models
have a flange (shown). Joint
should be sealed with RTV
(clear silicone).
Exterior opening
must be at least equal
to cross section of
exhaust duct.
Heater
stack
Roof
Wall
Provide independent
support for duct. Do not
rest weight on heater.
Duct must be
same size or larger
than heater's
exhaust outlet.
Armstrong
recommends no
bend sharper
than 45°.
Bird screen
installation is
recommended.