Supplyair Plenum Installation

NOTE: To avoid condensate freezing in the drain trap assembly and tubing, insulate around the drain trap assembly and all tubing located in unconditioned space.

NOTE:When converting the furnace, to horizontal left, ensure that the drainage port on the in-line drain assembly is downward as shown in Figure

4.If the in-line drain assembly is not rotated, then the furnace may not drain properly.

A.Installation on a concrete slab - *RL

1.Construct a hole in the ﬂoor per the dimensions in Figure 5.

2.Place the plenum and the furnace as shown in Figure 6.

B.Installation on a combustible ﬂoor - *RL

1.Cut hole and frame the hole per the dimensions in Figure 7.

2.Place sub-base for combustible ﬂoors over the hole with its duct collar extended downward. Attach the supply air plenum to the base in a manner which will as- sure 1” clearance to the ﬂooring or other combustible material. Place furnace on the combutsible base as shown in Figure 8.

3.When the furnace is installed on a fac- tory or site-built cased air conditioning coil, the sub-base is not necessary. However, the plenum attached to the coil casing must be installed such that its surfaces are at least 1” from combustible material in Figure 9.

CIRCULATING AIR SUPPLY

Plenums and air ducts must be installed in ac- cordance with the Standard for the Installation of Air Conditioning and Ventilating Systems (NFPA No. 90A) or the Standard for the Installation of Warm Air Heating and Air Conditioning Systems (NFPA No. 90B).

If outside air is utilized as return air to the furnace for ventilation or to improve indoor air quality, the system must be designed so that the return air to the furnace is not less than 50°F (10°C) during heating operation. If a combination of indoor and outdoor air is used, the ducts and damper system must be designed so that the return air supply to the furnace is equal to the return air supply under normal, indoor return air applications.

When a cooling system is installed which uses the furnace blower to provide airﬂow over the indoor coil, the coil must be installed downstream (on the outlet side) or in parallel with the furnace.

If a cooling system is installed in parallel with the furnace, a damper must be installed to prevent chilled air from entering the furnace and condens- ing on the heat exchanger.If a manually operated damper is installed, it must be designed so that operation of the furnace is prevented when the damper is in the cooling position and operation of the cooling system is prevented when the damper is in the heating position.

!WARNING:

Products of combustion must not be allowed to enter the return air ductwork or the circulating air supply. Failure to prevent products of combustion from being circulated into the living space can create potentially hazardous conditions including carbon monoxide poisoning that could result in personal injury or death.

All return ductwork must be secured to the furnace with sheet metal screws. For installations in conﬁned spaces, all return ductwork must be adequately sealed and joints must be taped.When return air is provided through the bot- tom of the furnace, the joint between the furnace and the return air plenum must be sealed.

The ﬂoor or platform on which the fur- nace is mounted must provide sound physical support of the furnace with no gaps, cracks, or sagging between the furnace and the ﬂoor or platform.

Return air and circulating air ductwork must not be connected to any other heat producing device such as a ﬁre- place insert, stove, etc.