Modine Manufacturing HD Series Installation And Service Manual page 7

InsTAllATIon - venTIng
diameter is necessary. If there is 6' or more of vent pipe in
the open space between the appliance and where the vent
pipe passes through the wall or floor, the thimble need only
be 2" greater than the diameter of the vent pipe. If a
thimble is not used, all combustible material must be cut
away to provide 6" of clearance. Where authorities have
jurisdiction, type B vent may be used for the last section
of vent pipe to maintain clearance to combustibles while
passing through wall or floor. See Figure 6.1. Any material
used to close the opening must be noncombustible.
A11. The following are General Instructions for Double Wall (type
B) Terminal Pipe Installation:
How to attach a single wall vent terminal to double wall
(type B) vent pipe:
1. Look for the "flow" arrow on the vent pipe.
2. Slide the vent terminal inside the exhaust end of the
double wall vent pipe.
3. Drill (3) holes through the pipe and the vent terminal.
Using 3/4" long sheet metal screws, attach the cap to
the pipe. Do not over tighten.
How to connect a single wall vent system to double
wall (type B) vent pipe:
1. Slide the single wall pipe inside the inner wall of the
double wall pipe.
2. Drill (3) holes through both walls of the single and
double wall vent pipes. Using 3/4" sheet metal screws,
attach the two pieces of pipe. Do not over tighten.
3. The gap between the single and double wall pipe must
be sealed, but it is not necessary to fill the full volume
of the annular area. To seal, run a large bead of 400°F
silastic around the gap.
A12. Vent termination clearances must be maintained:
Table 7.1 - vent Termination Clearances
structure
Forced air inlet within 10 feet
Combustion air inlet of another
appliance
Door, window, gravity air inlet,
or any building opening
Electric meter, gas meter, gas
regulator, and relief equipment ➀
Gas regulator ➀
Adjoining building or parapet wall
Adjacent public walkways
Grade (ground level)
➀ Do not terminate the vent directly above a gas meter or regulator.
➁ The vent must be at least 6" higher than anticipated snow depth.
A13. Do NOT use dampers or other devices in the vent or
combustion air pipes.
A14. Precautions must be taken to prevent degradation of
building materials by flue products.
A15. Single wall vent pipe must not pass through any
unoccupied attic, inside wall, concealed space, or floor.
A16. Uninsulated single wall vent pipe must not be used
outdoors for venting appliances in regions where the 99%
winter design temperature is below 32°F.
A17. The vent terminal must be:
Table 7.2 - vent Terminals
model size modine pn
30-75 5H0722850005
100-125 5H0722850001
minimum Clearances for
vent Terminal location
3 feet above
6 feet all directions
4 feet horizontal and below
1 foot above
4 feet horizontal (U.S.)
6 feet horizontal (Canada)
3 feet horizontal (U.S.)
6 feet horizontal (Canada)
6 feet all directions
7 feet all directions
3 feet above ➁
other listed Terminals
Gary Steel 1092
Gary Steel 1092
A18. In addition to following these General Instructions, specific
instructions for Vertical Category I or Horizontal Category
III vent systems must also be followed. Table 7.3 outlines the
differences:
Table 7.3 - AnsI unit Heater venting requirements
Category description
I Negative vent pressure
Non-condensing
II Negative vent pressure
Condensing
III Positive vent pressure
Non-condensing
IV Positive vent pressure
Condensing
Note: Vent connectors serving Category I appliances shall not be connected into
any portion of mechanical draft systems operating under positive pressure.
vertical Category I vent system determination
• Vertical vent systems terminate vertically (up).
• The horizontal portion of the vent run cannot exceed 75%
of the vertical rise (Example: If the vent height is 10 feet,
the horizontal portion of the vent system cannot exceed 7.5
feet).
• The vent terminates a minimum of 5' above the vent
connector on the unit.
• If the vent system to be installed meets ALL these criteria
(an example is shown in Figure 9.1), proceed to "Section
B – Vertical Vent System Installation". For all other cases,
proceed to the next section for Horizontal Category III Vent
System Determination:
Horizontal Category III vent system determination
• Horizontal vent systems terminate horizontally (sideways).
• A vent system that terminates vertically but has a horizontal
run that exceeds 75% of the vertical rise is considered
horizontal.
Horizontal vent configurations are Category III. For residential
installations, this requires the use of an agency approved
(UL1738) Category III vent system. Additional requirements,
including those for commercial and industrial installations are
covered in "Section C – Horizontal, Category III Vent System
Installation".
6-583.6
venting requirements
Follow standard
venting requirements.
Condensate must
be drained.
Vent must be gas tight.
Vent must be liquid and
gastight. Condensate
must be drained.
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