Modine Manufacturing PTP Installation And Service Manual page 9

InsTAllATIon - venTIng
section C – Horizontal, Category III vent system
Installation
C1. This section applies to horizontally vented Category III
vent systems and is in addition to "Section A – General
Instructions – All Units".
C2. Horizontal vent systems terminate horizontally (sideways).
C3. All seams and joints must be sealed with metallic tape or
silastic suitable for temperatures up to 400°F. Wrap the
tape 2 full turns around the vent pipe. For single wall vent
systems, 1 continuous section of double wall vent pipe may
be used within the vent system to pass through the wall to a
listed vent cap. Under no circumstances should 2 sections of
double wall vent pipe be joined together within 1 vent system
due to the inability to verify complete seal of inner pipes.
Refer to instruction A10 in "Section A – General Instructions –
All Units" for attaching double wall pipe to single wall pipe.
C4. All horizontal Category III vents must be terminated with a
listed vent cap. The cap must terminate a minimum distance
of 12" beyond the exterior wall surface as shown in Figure
9.2. The vent must be supported as shown in Figure 9.1.
Precautions must be taken to prevent degradation of building
materials by flue products.
figure 9.1 - exhaust vent Construction Through
Combustible Walls and support Bracket
METAL
SLEEVE
2" MIN.
VENT PIPE
DIAMETER
METAL FACE
METAL
SLEEVE
2" MIN.
1"
C5. When condensation may be a problem, the vent system shall
not terminate over public walkways or over an area where
condensate or vapor could create a nuisance or hazard or
could be detrimental to the operation of regulators, relief
openings, or other equipment.
C6. The venting system must be exclusive to a single unit, and
no other unit is allowed to be vented into it.
C7. When vented horizontally, maintain a 1/4" per foot rise away
from the heater and place a drip leg with clean out near the
unit as shown in Figure 9.2. Where local authorities have
jurisdiction, a 1/4" per foot downward slope is acceptable
with a drip leg and clean out near the exit of the vent as
shown in Figure 9.2, or allow the condensate to drip out the
end.
figure 9.2 - Horizontal venting
FIBER GLASS
INSULATION
MIN. 2"
12" MIN
PLATE
1"
9"
VENT TERMINATION
45 SUPPORT BRACKET
9" (where required)
(Make from 1" x 1" steel angle)
C8. For a vent termination located under an eave, the distance
of the overhang must not exceed 24". The clearance to
combustibles above the exterior vent must be maintained
at a minimum of 12". Consult the National Fuel Gas Code
for additional requirements for eaves that have ventilation
openings.
C9. Once venting is complete, proceed to the section titled
"Installation – Gas Connections".
6-560.4
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