AIR Ducts, General Requirements | Carrier 58CTA/CTX manual

LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET AND BUILDING JOISTS,
STUDS, OR FRAMING.	17 3/4″ (451mm)OVERALL
	4 3/4″ (121mm) UNDER DOOR
	1″ (25mm) UNDER FURNACE

EQUIPMENT MANUAL SHUT-OFF GAS VALVE

SEDIMENT

TRAP

GAS			TYPE-B			EXTEND OUT 12″ (305mm)
ENTRY			VENT			FROM FACE OF DOOR
						FROM FACE OF DOOR
		IN	*	(15	2mm)
	6″ M			(15

					30-IN. (762mm)
							* WHEN USED WITH

					MIN WORK AREA
							SINGLE WALL VENT
							CONNECTIONS
17 3/4″ (451mm)
SHEET
METAL	(559mm)
22″	(559mm)
22″

UNION

A03177

58CT

Fig. 17 - Typical Attic Installation

Not all horizontal furnaces are approved for side return air connections. (See Fig. 20.)

FILTER ARRANGEMENT

!WARNING

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal injury, or death.

Never operate a furnace without a filter or with filter access door removed.

There are no provisions for an internal filter rack in these furnaces. An external filter rack is required.

This furnace is shipped with a factory-supplied Media Filter Cabinet. The Media Filter Cabinet uses either a factory-supplied standard 3/4-in. (19 mm) filter or 4-in. (102 mm) wide Media Filter which can be purchased separately.

Refer to the instructions supplied with Media Cabinet for assembly and installation options.

AIR DUCTS

General Requirements

The duct system should be designed and sized according to accepted national standards such as those published by: Air Conditioning Contractors Association (ACCA), Sheet Metal and Air Conditioning Contractors National Association (SMACNA) or American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) or consult The Air Systems Design Guidelines reference tables available from your local distributor. The duct system should be sized to handle the required system design CFM at the design external static pressure. The furnace airflow rates are provided in Table 5-Air Delivery CFM (With Filter).

When a furnace is installed so that the supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall also be handled by duct(s) sealed to the furnace casing and terminating outside the space containing the furnace.

Secure ductwork with proper fasteners for type of ductwork used. Seal supply- and return-duct connections to furnace with code approved tape or duct sealer.

NOTE: Flexible connections should be used between ductwork and furnace to prevent transmission of vibration.

Ductwork passing through unconditioned space should be insulated to enhance system performance. When air conditioning is used, a vapor barrier is recommended.

Maintain a 1-in. (25 mm) clearance from combustible materials to supply air ductwork for a distance of 36 in. (914 mm) horizontally from the furnace. See NFPA 90B or local code for further requirements.

Ductwork Acoustical Treatment

NOTE: Metal duct systems that do not have a 90_ elbow and 10 ft. (3 M) of main duct to the first branch take-off may require internal acoustical lining. As an alternative, fibrous ductwork may be used if constructed and installed in accordance with the latest edition of SMACNA construction standard on fibrous glass ducts. Both acoustical lining and fibrous ductwork shall comply with NFPA 90B as tested by UL Standard 181 for Class 1 Rigid air ducts.

Supply Air Connections

For a furnace not equipped with a cooling coil, the outlet duct shall be provided with a removable access panel. This opening shall be accessible when the furnace is installed and shall be of such a size that the heat exchanger can be viewed for possible openings using light assistance or a probe can be inserted for sampling the air stream. The cover attachment shall prevent leaks.

Upflow and Horizontal Furnaces

Connect supply-air duct to flanges on furnace supply-air outlet. Bend flange upward to 90_ with wide duct pliers. (See Fig. 14.) The supply-air duct must be connected to ONLY the furnace supply-outlet-air duct flanges or air conditioning coil casing (when used). DO NOT cut main furnace casing side to attach supply air duct, humidifier, or other accessories. All accessories MUST be connected to duct external to furnace main casing.