Empire Comfort Systems MILLIVOLT DVCP36SP30N-1 Installation Instructions And Owner's Manual page 30

Locate and mark the center point of the vent pipe using a nail on
the underside of the roof. Drive the nail through the center point.
Mark the outline of the roof hole around this center point.
NOTICE: Size of the roof hole dimensions depend on the pitch
of the roof. There must be a 1 inch clearance to the vertical pipe
sections. This clearance is to all combustible material.
Cover the opening of the vent pipe and cut and frame the roof
hole. Use framing lumber the same size as the roof rafters and
install the frame securely. Flashing anchored to frame must
withstand high winds. The storm collar is placed over this joint
to make a water-tight seal. Appropriate sealant acceptable
for temps up to 300°F should be used to completely seal this
flashing installation.
Determining Minimum Vent Height Above the Roof.
Major U.S. building codes specify minimum chimney and/
or vent height above the roof top. These minimum heights
are necessary in the interest of safety. These specifica-
tions are summarized in Figure 49.
ROOF PITCH
Flat to 6/12
6/12 to 7/12
Over 7/12 to 8/12
Over 8/12 to 16/12
Over 16/12 to 21/12
Note that for steep roof pitches, the vent height must be
increased. In high wind conditions, nearby trees, adjoining roof
lines, steep pitched roofs, and other similar factors can result in
poor draft, or down-drafting. In these cases, increasing the vent
height may solve this problem.
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VENTING FIREPLACE - TOP
VERTICAL TERMINATION
WARNING
H (Min.)
(Dimensions in Inches)
12
15
18
24
36
Figure 49
General Maintenance
Inspect venting system semi-annually as follows:
1. Check for corrosion areas of the venting system exposed
to the elements. These will appear as rust spots or streaks
and, in extreme cases, holes. Replace damaged components
immediately.
2. Remove the cap and shine a flashlight down the vent.
Remove any bird nests or other foreign material.
3. Check for evidence of excessive condensate, such as water
droplets forming in the inner liner and subsequently dripping
out at joints. Condensate can cause corrosion of caps, pipe
and fittings. It may be caused by having excessive lateral
runs, too many elbows and exterior portions of the system
being exposed to cold weather.
4. Inspect joints to verify that no pipe sections or fittings have
been disturbed and, consequently, loosened. Also, check
mechanical supports, such as wall straps or plumbers' tape
for rigidity.
A removable panel or other means must be provided in the
enclosure for visual inspection of the flue connection.
NOTICE: This also pertains to vertical vent systems installed on
the outside of the building.
Slide the vertical vent cap over the ends of the vent pipe and
secure. See Figure 50.
Figure 50
36092-10-0619