Carrier 48PG20-28 specifications Install Flue Hood and Inlet Hood, Concentric Duct Details

NOTE: Dimensions A, A′, B, and B′ are obtained from field-supplied ceiling diffuser.

Shaded areas indicate block-off pans.

Fig. 9 — Concentric Duct Details

Step 6 — Install Flue Hood and Inlet Hood —

Flue hood (smaller hood), inlet hood (larger hood), and screens are shipped inside the unit in the fan section. To install, remove the heat panel. The flue hood is attached to the heat section panel from the outside using the screws provided. See Fig. 10.

The inlet hood is installed by inserting the hood through the back of the heat panel. Attach the hood by inserting the screws provided through the clearance holes in the heat panel and into the intake hood.

Install the screens into both hoods using the screws and re- taining nuts provided with the unit.

Attach the cover of the observation hole on the intake hood and then replace the heat panel onto the unit to complete the in- stallation.

NOTE: When properly installed, the flue hood will line up with the combustion fan housing. See Fig. 11.

Step 7 — Trap Condensate Drain — See Fig. 12 for drain location. One 3/4-in. half coupling is provided outside unit evaporator section for condensate drain connection. A trap at least 4-in. deep must be used. See Fig. 13.

All units must have an external trap for condensate drain- age. Install a trap at least 4 in. deep and protect against freeze- up. If drain line is installed downstream from the external trap, pitch the line away from the unit at 1 in. per 10 ft of run. Do not use a pipe size smaller than the unit connection.

Step 8 — Install Gas Piping — Unit is equipped for use with natural gas. Refer to local building codes, or in the absence of local codes, to ANSI Z223.1-latest year and addendum Z223.1A-latest year entitled NFGC. In Canada, installation must be in accordance with the CAN1.B149.1 and CAN1.B149.2 installation codes for gas burning appliances.

Support gas piping. For example, a 3/4-in. gas pipe must have one field-fabricated support beam every 8 ft. Therefore, an 18-ft long gas pipe would have a minimum of 3 support beams.

Install field-supplied manual gas shutoff valve with a 1/8-in. NPT pressure tap for test gage connection at unit. The pressure tap is located on the gas manifold, adjacent to the gas valve. Field gas piping must include sediment trap and union. See Fig. 14.

FLUE HOOD

INLET HOOD

Fig. 10 — Flue and Inlet Hood Locations

COMBUSTION

FAN HOUSING

HEAT

EXCHANGER

SECTION INDUCED-DRAFT MOTOR

MAIN BURNER

SECTION

Fig. 11 — Combustion Fan Housing Location

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