MECHANICAL DRAFT APPLICATIONS
5
• Condensation of flue gasses.
• Positive outlet draft conditions.
• Reverse flow of fluegas during or after burner shutdown.
In addition, the following rules of good industry practice should be followed;
• Always try to keep chimney connector length to ten feet (10'), or less.
• The chimney connector must never be smaller than the boiler flue outlet, and
should be constructed of at least 24-gauge metal.
It is important to note that due to the high efficiency of the MUNCHKIN OFB boilers con-
densing temperatures in the chimney connector and venting system may be reached.
If condensing temperatures of below 250 °F NET are reached in the chimney connector, the
following precautions may have to be taken;
• Seal all joints in venting system with high temperature silicone or mastic.
• Verify quality of chimney and liner. If a masonry, brick, or block chimney is used, or
the existing tile liner is in poor condition, a chimney liner suitably rated, and listed
for oil may have to be installed.
PART IV. MECHANICAL DRAFT APPLICATIONS
When using the MUNCHKIN OFB boilers in a mechanical draft application, the following
basic guidelines should be observed according to the venting system in use. In addition, it
is strongly recommended that the applicable precautions for Natural Draft Applications be
used.
In addition to all of the pertinent information regarding Natural Draft Applications whenever
a Mechanical Draft Application is used, it should be installed using the following instructions
and
Figure 2, page 6
as reference;
• The terminating vent hood, and the inlet air hood should be on the same wall sur-
face, and on the wall opposite from the prevailing wind wall, if possible.
• All of the air for combustion to the burner is supplied directly from outside of the
building or structure, following the suggested applications below.
•
Not less than 12" above the total accumulated snow and level grade.
•
Not less than 4' horizontally or below any window, door or air inlet, and also
not more than 1' above any of these openings.
•
Not less than 3' above a powered air inlet device that is within 10'.
•
Not less than 2' from any other building.
•
At least 3' from any inside corner of a building.
WARNING
• NEVER connect the appliance into a chimney or liner serving an open fireplace.
• Inspect and clean chimney, and verify it is free of restrictions and obstructions.
• The chimney connector must always be properly supported.
• NEVER install a manual damper in the venting system.
• Chimney connectors should be free of as many 90° degree turns as possible, and
be pitched upwards towards the vent.
