CONNECTING THE VENT DAMPER
AND VENT CONNECTOR
Refer to Fig. 1 flue diagram for the size and location of the
vent (flue opening). Use a 28 gauge (minimum) galvanized
pipe to connect to the chimney
- The damper
blade on the furnished vent
damper has a V2square inch hole (approximately 3/4"diame-
ter). On boilers equipped with standing pilot, the hole must
be teft open. On boilers equipped with intermittent ignition,
the hole should be plugged by using the plug supplied with
the vent damper.
1. Position furnished vent damper on top of flue outlet collar.
Fasten damper securely to flue outlet collar with sheet
metal screws. Make sure damper blade has clearance
to operate inside of diverter.
On 2 section boilers equipped
with vent damper, the
4-inch vent damper is equipped with a 3- to
4-inch adapter so that the 4-inch vent damper may be
installed on the boiler's 3-inch flue outlet collar Fasten
all fittings securely
As An Option
The damper may be installed in any horizontal or vertical
position, closer to the flue outlet collar preferred. Follow
the diagrams - Figures 9, 10 and 11.
2. Install the vent damper to service only the single boiler
for which it is intended. The damper position indicator
shall be in a visible location following installation. Locate
the damper so that it is accessible for servicing.
3. The damper must be in the open position when appliance
main burners are operating.
4, The boiler is equipped with a factory wired harness that
plugs into the vent damper.
5. Vent pipe must be same size as the flue outlet collar,
except 2 section boilers with vent damper as noted above.
6. Slope pipe up from boiler to chimney not less than 1/4"
7. Run pipe as directly as possible with as few elbows as
8. Do not connect to fireplace flue.
9. End of vent pipe must be flush with inside face of chimney
flue. Use a sealed-in thimble for the chimney connection.
10. Horizontal run should not be longer than 3/4the chimney
height (HT) (Fig. 8).
The sections of vent pipe should be fastened with sheet metal
screws to make the piping rigid. Horizontal portions of the
vent system must be supported
to prevent sagging.
stovepipe wires every 5' to support the pipe from above.
If the vent pipe must go through a crawl space, double wall
vent pipe should be used. Where vent pipe passes through
a combustible wall or partition, use a ventilated metal thimble.
The thimble should be 4 inches larger in diameter than the
Up to 100,000
Up to 155,000
Up to 230,000
Up to 350,000
FLUE AREA IN INCHES
25 Ft. Up
*HT - top of thimble to fop of flue See Fig 8
For boiler input refer to table, page 2.
only - not meant to imply mm_rnurn sizes
VENT PiPE CLEARANCE
Wood and other combustible
materials must not be closer
than 6' from any surface of single wall metal vent pipe. Listed
Type B vent pipe or other listed venting systems shall be
installed in accordance with their listing.
When an existing boiler is removed from a common venting
system, the common venting system is likely to be too large
for proper venting of the appliances remaining connected
At the time of removal of an existing boiler, the following
steps shall be followed
connected to the common venting system placed in operation,
while the other appliances
common venting system are not in operation.
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and other deficiencies which
could cause an unsafe condition.
3. Insofar as is practical, close all building doors and windows
and all doors between the space in which the appliances
remaining connected to the common venting system are
located and other spaces of the building. Turn on clothes
dryers and any appliance not connected to the common
venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they will operate at
maximum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.
4. Place in operation the appliance being inspected. Follow
the lighting instructions. Adjust thermostat so appliance
will operate continuously.
5, Test for spillage at the draft hood relief opening after 5
minutes of main burner operation. Use the flame of a match
or candle, or smoke from a cigarette, cigar or pipe.
6. After it has been determined that each appliance remain-
ing connected to the common venting system properly
vents when tested
windows, exhaust fans, fireplace dampers and any other
gas-burning appliance to their previous conditions of use.