Bryant 345MAV instruction manual II. COMBUSTION-AIR and Vent Piping, General, Combustion Air Pipe

7.If improper venting is observed during any of above tests, the venting system must be corrected.

Vent system or vent connectors may need to be resized. For any other appliances when resizing vent systems or vent connectors, system or connector must be sized to approach minimum size determined in appropriate table in NFGC or NSCNGPIC.

II.COMBUSTION-AIR AND VENT PIPING

A.General

WARNING: Solvent cements are combustible. Keep away from heat, sparks, and open flame. Use only in well-ventilated areas. Avoid breathing in vapor or allow- ing contact with skin or eyes. Failure to follow this warning could result in fire, property damage, personal injury, or death.

→Combustion-air and vent pipe fittings must conform to American National Standards Institute (ANSI) standards and American Society for Testing and Materials (ASTM) standards D1785 (schedule-40 PVC), D2665 (PVC-DWV), D2241 (SDR-21 and SDR-26 PVC), D2661 (ABS-DWV), F628 (schedule-40 ABS), or F891 (PVC-DWV cellular core) or F441 schedule-40 CPVC pipe) and F438 (schedule-40 CPVC fittings). Pipe cement and primer must conform to ASTM standards D2564 or F493 (PVC or CPVC) or D2235 (ABS).

In Canada construct all combustion-air and vent pipes for this unit of CSA or ULC certified schedule-40 PVC, PVC-DWV or ABS-DWV pipe and pipe cement. SDR pipe is NOT approved in Canada.

B. Combustion Air Pipe

CAUTION: Combustion air must not be taken from inside a structure that is frequently contaminated by halogens, which include fluorides, chlorides, bromides, and iodides. These elements are found in aerosols, detergents, bleaches, cleaning solvents, salts, air freshen- ers, adhesives, paint, and other household products. Locate combustion-air inlet as far as possible from swimming pool and swimming pool pump house.

Excessive exposure to contaminated combustion air will result in safety and performance related problems.

NOTE: Furnace combustion-air connections are sized for 2-in. pipe. The combustion-air pipe will be 2-in. diameter in all installations.

Furnace combustion-air connection must be attached as shown in Fig. 28. Combustion-air intake housing plug may need to be relocated in some applications.

Combustion-air pipe must terminate outside of furnace casing with 1 elbow. Orient elbow so that opening faces down for upflow or downflow applications. Orient elbow so that it faces sideways (left or right) for horizontal left or horizontal right applications. (See Fig. 28.) Maintain a 3-in. minimum clearance between the opening of the combustion-air inlet pipe and any object.

NOTE: All pipe joints must be watertight except attachment of combustion-air inlet pipe to inlet housing connection, since it may be necessary to remove pipe for servicing.

Install combustion air inlet pipe as follows:

1.Assemble combustion-air inlet pipe.

a.Permanently install perforated disk assembly (factory- supplied in loose parts bag) in combustion-air elbow using RTV or by cementing. (See Fig. 29.)

For 120,000 Btuh size units only: Separate the 2 halves of perforated disk assembly and use only the shouldered disk half.

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b.Determine length of straight portion of combustion-air inlet pipe from table in Fig. 29.

c.Cut field-supplied 2-in diameter PVC pipe to determined length.

d.Permanently attach elbow/perforated disk assembly to straight portion of pipe using RTV or by cementing. (See Fig. 29.)

2.Attach combustion-air inlet pipe.

NOTE: Select 1 vent pipe connection and							NOTE: Select 1 vent pipe connection and
		1 combustion-air pipe connection.						1 combustion-air pipe connection.
				AIR
COMBUSTION-			FLOW COMBUSTION-				VENT
AIR						AIR			VENT
	VENT				VENT

	COMBUSTION-	COMBUSTION-
	AIR	AIR	AIR
	FLOW
UPFLOW	DOWNFLOW
COMBUSTION-	COMBUSTION-
AIR	AIR	VENT
VENT
AIR			AIR
FLOW			FLOW

HORIZONTAL-LEFT DISCHARGE HORIZONTAL-RIGHT DISCHARGE

A96188

CAUTION: Make sure there is adequate clearance (3-in. minimum) to any fixed or loose objects in order to ensure an adequate combustion-air supply.

Fig. 28ÐCombustion-Air and Vent Pipe Connections

a. Determine location of combustion-air intake pipe con- nection to combustion-air intake housing as shown in Fig. 28 for application.

b.Reposition combustion-air intake housing plug fitting in appropriate unused intake housing connection.

c.Install pipe support (factory-supplied in loose parts bag) into selected furnace casing combustion-air pipe hole. Pipe support should be positioned at bottom of casing hole.

d.Insert assembled combustion-air inlet pipe into intake housing.

e.Make sure elbow is oriented in an acceptable direction and that the minimum clearance of 3 in. is observed. (See Fig. 28.)

f.Drill a 1/8-in. hole in 2-in. combustion-air inlet pipe using hole in intake housing as a guide.

g.Install a field-supplied No. 6 or No. 8 sheet metal screw into combustion-air pipe.