Bryant 345MAV instruction manual ÐCombustion-Air Inlet Pipe Assembly

FIELD-SUPPLIED
2-IN. DIAMETER	FIELD-SUPPLIED
PVC 90°ELBOW
	2-IN. DIAMETER
	PVC PIPE

A

COMBUSTION-AIR DISC (FACTORY-SUPPLIED IN

NOT IN HORIZONTAL SECTION

FURNACE

PIPE DIAMETER

TRANSITION IN

VERTICAL SECTION

A93034

LOOSE PARTS BAG)

A96211

LENGTH OF STRAIGHT PIPE PORTION OF

COMBUSTION-AIR INLET PIPE ASSEMBLY (IN.)

CASING WIDTH	A
17-1/2	8-1/2 ± 1/2
21	10-1/2 ± 1/2
24-1/2	12 ± 1/2

Fig. 29ÐCombustion-Air Inlet Pipe Assembly

NOTE: Do not attach combustion-air intake pipe permanently to combustion-air intake housing since it may be necessary to remove pipe for service of ignitor or flame sensor.

The combustion-air intake plug fitting must be installed in unused combustion-air intake housing. This fitting must be attached by using RTV sealant, or by drilling a 1/8-in. hole in fitting, using hole in intake housing as a guide. Install a field-supplied No. 6 or No. 8 sheet metal screw.

NOTE: DO NOT OVERTIGHTEN SCREW. Breakage to intake housing or fitting may cause air leakage to occur.

A plugged drain connection has been provided on this fitting for use when moisture is found in combustion-air intake pipe and combustion box. If use of this drain connection is desired, drill out fitting's tap plug with a 3/16-in. drill and connect a field-supplied 3/8-in. tube. This tube should be routed to open condensate drain for furnace and A/C (if used), and should be trapped. (See Fig. 30.)

	HOUSING	COMBUSTION–AIR
	PLUG
		INTAKE HOUSING
3/8″ ID TUBE
		BURNER
		BOX
3/16″
DRILL		COMBUSTION–
		AIR PIPE
	4″￿
TRAP	MIN
TO OPEN
	DRAIN
		A96190

Fig. 31ÐVent Pipe Diameter Transition Location and

Elbow Configuration

Determine vent pipe diameter and maximum pipe lengths using Table 4.

Furnace vent pipe connection must be attached as shown in Fig.

28.Inducer housing alternate vent cap may need to be relocated in some applications.

NOTE: Starting at furnace, slope vent pipe a minimum of 1/4 in. per linear ft upward to termination(s) with no sags between hangers.

CAUTION: When vent pipe is exposed to temperatures below freezing, such as when it passes through an unheated space or when a chimney is used as a raceway, pipe must be insulated as described in Table 5 with Armaflex-type insulation.

WARNING: Vent pipes must be airtight and watertight. Failure to follow this warning could result in property damage, personal injury, or death.

NOTE: The minimum vent pipe length for these furnaces is 5 ft. Short pipe lengths (5-8 ft) may discharge water droplets. These droplets may be undesirable, and a 12-in. minimum offset pipe section is recommended to reduce excessive droplets from exiting vent pipe outlet. (See Fig. 32.)

NOTE: Do not count elbows or pipe sections in terminations or within furnace. See shaded areas in Fig. 34.

EXAMPLE:

An 036080 size furnace located in Indianapolis, eleva- tion 650 ft above sea level, could be installed in an application requiring 3 elbows and 32 ft of vent pipe. Table 4 indicates this application would allow a 2-in. diameter vent pipe. At 0-2000 ft elevation, 2-in. pipe is good for up to 35 ft with 3 elbows. If same installation were in Albuquerque, elevation 5250 ft above sea level, installation would require 2-1/2 in. vent pipe. At 5001- to 6000-ft elevation, 2-in. pipe is allowed for up to 23 ft with 3 elbows, but 2-1/2 in. pipe can be used for up to 70 ft with 3 elbows.

Fig. 30ÐIntake Housing Plug Fitting Drain

C.Vent Pipe

NOTE: Furnace vent pipe connections are sized for 2-in. pipe. Any vent pipe size change should be made outside furnace casing in vertical pipe. (See Fig. 31.) This allows proper drainage of vent condensate.

Install vent pipe as follows:

1.Determine location of vent pipe connection to inducer housing as shown in Fig. 28 for application.

→2. Reposition elastomeric (rubber) inducer housing outlet cap and clamp to appropriate unused inducer housing connec- tion. Tighten clamp.

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