Reznor X Unit Installation Manual - Manual (Page 10)

Form I-X, P/N 150491 R10, Page 10
6.0 Mechanical
(cont'd) 2. The unit is equipped with a built-in draft diverter, consequently an external draft
diverter MUST NOT be installed in the vent connector or any internal alterations
made. Do not install a manual damper or other fixed restriction in the vent
connector.
3. Vent pipe should be a minimum of 26-gauge galvanized steel or other non-
corrosive material. Double-wall, Type B vent pipe such as Metalbestos or
Amerivent is recommended. ( NOTE: Double-wall pipe is not available in 9"
diameter.) Where it is necessary to run the vent pipe through an exterior wall of
combustible materials, a suitable thimble must be used. The vent pipe shall have
a clearance of at least six inches (152mm) from combustible materials or as is
specified by the double-wall vent pipe manufacturer.
4. With the outlet on the heater in the horizontal position, it is recommended that a
12-18" (305-457mm) piece of straight pipe be connected to the flue collar before
installing an elbow. The horizontal vent pipe run should have a uniform rise of at
least 1/4" per foot of horizontal run in the direction of discharge. The length of the
lateral run must not exceed lengths shown in the vent tables of the National Fuel
Gas Code or the Canadian Installation Code for Gas Burning Appliances (See Vent
Tables below).
5. Support horizontal runs every six feet (1.8M). Support vertical runs of type
"B" double-wall vent pipe in accordance with the requirements of the pipe
manufacturer. Support single-wall vertical pipe in accordance with accepted
industry practices. Do not rely on the heater for support of either horizontal or
vertical pipes. Use non-combustible supports.
6. Vent connectors serving Category I heaters shall not be connected into any portion
of a mechanical draft system operating under positive pressure.
7. Where it is necessary to use a long run of vent pipe, or where the vent pipe is
exposed to cold air, condensation within the pipe may occur. There are two ways
to overcome or eliminate this problem.
(a) Prevent condensation by insulating the pipe so that the temperature of the flue
products never drops below 250°F.
(b) Use double-wall, Type B vent pipe which is recommended for the reduction or
elimination of condensate problems. Where extreme conditions are present
and condensate is anticipated, install a trap for collecting condensate.
8. The vent connection may be made into a suitable permanent chimney or into a
gas vent. The effective area of the vent connector, gas vent or chimney when
connected to a single appliance shall not be less than the area of the appliance
drafthood outlet or in accordance with approved venting methods. The effective
area of the gas vent or chimney when connected to more than one appliance shall
not be less than the area of the largest vent connector plus 50% of the areas of
additional vent connectors or in accordance with approved venting methods.
Minimum permissible height of the vertical vent is 5 feet (1.5M) providing no
horizontal vent pipe connector is used. If a horizontal vent connector is necessary,
consult Tables below or the National Fuel Gas Code or the Canadian Installation
Code for Gas Burning Appliances, for the maximum permissible length of a
horizontal pipe run (vent connector) for a given vertical height of gas vent.
The gas vent or chimney should extend at least 3 feet (1M) above the highest point
where it passes through a roof of a building and at least 2 feet (.6M) higher than
any portion of a building or obstruction within a horizontal distance of 10 feet (3M).
Install a Reznor Option CC1 vent cap on the end of the vent pipe to prevent rain
or snow from entering the open end. ( NOTE: When installing a Size 125, run the
required 7" vent pipe and use a field-supplied increaser to attach an 8" vent cap.)
9. If the heater is installed in a space served by a large exhaust fan, be sure that the
exhaust fan does not affect the operation of the heater or the satisfactory venting
of its products of combustion.
If a negative pressure exists, as evidenced by a downdraft, a factory-designed
mechanical motor drive venter (Option CA) should be installed. In severe negative
pressure conditions, makeup air equipment may be necessary.
6.2.1 Venting Requirements (cont'd)
6.2 Venting (cont'd)