Filters:
Air filters must be used in every installation. For side return installations, air filters must be installed external to the furnace casing. An external filter rack kit with filter (parts No. 20069901 or Cat. No. 68L75 12 / 15½" x 25" sizes and 20069902 or Cat. No. 68L76 for 15½" / 19" x 25" sizes) is available as an optional accessory.
For bottom (end) return installations, the above optional external rack may be used, if the unit was not provided with a internal filter. Minimum filter size and suggested filter materials are shown in Table 3. (If different type filter is used, it must be an equivalent high airflow capacity.)
Table 3 | EXTERNAL FILTER RACK SIZE | |||
MODEL |
| SIDE | BOTTOM/END | |
| RETURN | RETURN | ||
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| |||
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| 15 ½ X 25 | 12 X 25 | ||
| ||||
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|
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| |
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| 15 ½ | X 25 | 15 ½ X 25 | |
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|
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|
|
| 15 ½ | X 25 | 19 X 25 | |
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This furnace may use either a disposable filter, permanent filter, electronic or high efficiency media air
cleaner. Consult filter/cleaner manufacturers for maintience service and static pressure drop for air moving requirements.
When installing the furnace with cooling equipment for year round operation, the following recommendations must be followed for series or parallel air flow:
1.In series flow applications, the evaporator coil is mounted after the furnace in an enclosure in the supply air stream. The furnace blower is used for both heating and cooling airflow.
2.In parallel flow installation, dampers must be provided to direct air over the furnace heat exchanger when heat is desired and over the cooling when cooling is desired. At no time may the evaporator coil be located on the return air side of the heat exchanger.
IMPORTANT: The dampers should be adequate to prevent cooled air from entering the furnace, and if manually operated, must be equipped with means to prevent operation of either the cooling unit or furnace unless the damper is in the full cool or full heat position.
The coil MUST be installed on the air discharge side of the furnace. Under no circumstances should the air flow be such that cooled, conditioned air can pass over the furnace heat exchanger. This will cause condensation in the heat exchanger and possible failure of the heat exchanger that could lead to a fire hazard and/or hazardous conditions that may lead to bodily harm. Heat exchanger failure due to improper installation will not be covered by warranty.
VENTING
Venting for this category I furnace must be to the outside and in accordance with local codes or requirements of the local utility. In the absence of local codes, venting must conform to the applicable sections of the latest edition of the (U.S.) National Fuel Gas Code ANSI Z223.1/NFPA54, and/or CSA B149.1 Natural Gas and Propane Installation Codes, and the vent manufacturers instructions.
This furnace is CSA International certified as a Category I forced air appliance and can not be vented into a vent system with any Category II, III or IV appliance. It must be vented vertically, or nearly vertically, unless installed with a listed mechanical venter in accordance with horizontal venting instructions. It must not be connected to any portion of a mechanical draft system operating under positive pressure
The 3" (in.) to 4" (in.) vent adaptor coupling (supplied with unit) MUST BE USED. It must be connected directly to the outlet of the combustion blower using a field supplied corrosion resistant sheet metal screw (See Figure 8).
Figure 8
VENT ADAPTOR MOUNTING
Pre-Installation Vent System Inspection:
Before this furnace is installed, it is highly recommended that any existing vent system be completely inspected.
For a chimney or "B" vent, this should include the following:
1. Inspection for any deterioration in the chimney or "B"
20571201 | Issue 0527 | Page 12 of 28 |