Lennox Hearth MERIT PLUS MP-36OD User Manual

Page 15

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

This suggestion is provided in the interest of
better operation. If the terminations are located
too close to each other, smoke may migrate
from one fl ue into the other.

FTF8 CHIMNEY COMPONENT
CALCULATIONS

The minimum installed height of the completed
fi replace system is 15' 0" for indoor installa-
tions and 7' 3" for outdoor installations. The
maximum height is 60' 0."

MULTIPLE TERMINATIONS

If more than one termination is located in the
same chase or within the same general prox-
imity, we suggest they should be separated
in distance at least 24" horizontally from fl ue
center to fl ue center and stacked or staggered
vertically at least 18" apart, from the termination
of one smoke exit to the termination of another
smoke exit (Figure 44).

Note: It is recommended that all exterior ex-
posed metal fi replace components; such as
terminations, fl ashings, storm collars and/or
fl ue be painted with a premium quality, high
temperature, rust preventative paint designed
for metal. This is especially important when
installations are made in abnormally adverse
or corrosive environments; such as near lakes,
oceans or in areas with consistently high
humidity conditions. Consult the paint manu-
facturers instructions for proper preparation
and application.

TEN FOOT RULE SUMMARY

The minimum chimney height above the roof
and/or to adjacent walls and buildings is speci-
fi ed by all major building codes.

If the horizontal distance from the peak of the
roof is less then 10', the top of the chimney must
be at least 2' above the peak of the roof.

If the horizontal distance from the chimney
edge to the peak of the roof is more than 10' a
chimney height reference point is established
on the roof surface 10' horizontally from the
chimney edge. The top of the chimney must
be at least 2' above this reference point. In all
cases, the chimney cannot be less then 3' above
the roof at the edge of the chimney.

The 2' in 10' rule is necessary in the interest
of safety but does not ensure smoke-free op-
eration. Trees, buildings, adjoining roof lines,
adverse wind conditions, etc., may require a
taller chimney should the fi replace not draft
properly (refer to Figure 43).

Less Than 10'

Min

2' Min.

10'

Min

CTD

18"

24"

CTDT

Figure 43

Figure 44

To determine the number of chimney sections
and chimney components required, follow
these steps:

1. Determine total vertical height of the fi replace
installation. This dimension is the distance from
the surface the fi replace sets on to the point
where smoke exits from the termination.

2. Determine the number of chimney compo-
nents required, except chimney sections. This
would include fi restop spacers, stabilizers, roof
fl ashing, etc.

3. The effective heights of the components
are:

The Fireplace

= 36 1/4"

FTF8-12 =

1/4"

FTF8-18 =

1/4"

FTF8-36 =

341/4"

FTF8-48 =

1/4"

FTF8-CTD Termination

= 4"

FTF8-CT1 Termination

= 12" to 18"

FTF8-CT2 Termination

= 15" to 23"

FTF8-CTDT Termination

= 12" to 18"

FTF8-CTDTM Termination = 4"

FTF8-S4 Stabilizer *

= 3"*

* Required for every 30' of vertical chimney
and/or 10' of offset chimney.

4. Determine amount of chimney height required
by subtracting total combined height of all pre-
selected components (fi replace and chimney
components from total desired height).

Reference Vertical Elevation Chart and determine
the number of chimney sections (quantity and
length) required.

SPECIAL OFFSET INSTRUCTIONS

To clear any overhead obstructions, you may
offset your chimney system using Security
Chimneys 30° offset and return elbows. Use
two elbows - an offset elbow to initiate the
offset and a return elbow to terminate it. A
30° offset elbow, angling in any direction, may
be the fi rst component used off the top of the
fi replace fl ue collar.