Raypak 302A-902A manual Installation, Common Venting System, Certified

WARNING: Vent connectors serving appliances vented by natural draft shall not be connected into any portion of mechanical draft systems operating under a positive pressure.

Horizontal Through-the-Wall Venting (Category IV)

Fig. 38: Horizontal Through-the-Wall Venting

(Category IV)

Installation

These installations utilize the boiler-mounted blower to vent the combustion products to the outdoors. Combustion air is taken from inside the room and the vent is installed horizontally through the wall to the out- doors. Adequate combustion and ventilation air must be supplied to the mechanical room in accordance with the NFGC (U.S.) and B149.1 (Canada).

The total length of the horizontal through-the-wall ex- haust vent system should not exceed 70 ft in length. If horizontal run exceeds 70 ft, an appropriately sized extractor must be used. To maintain proper operation,

pressure reading must be between -0.01 and -0.1 in. WC as measured 12 in. from the appliance flue outlet. Each elbow used is equal to 10 ft of straight pipe. This will allow installation in one of the four following com- binations:

•70’ of straight flue pipe

•60’ of straight flue pipe and one elbow

•50’ of straight flue pipe and two elbows

•40’ of straight pipe and three elbows

The vent cap is not considered in the overall length of the venting system.

The vent must be installed to prevent flue gas leakage. Care must be taken during assembly to ensure that all joints are sealed properly and are airtight. The vent must be installed to prevent the potential accumulation of condensate in the vent pipes. It is recommended that:

1.The vent must be installed with a slight upward slope of not more than 1/4 in per foot of horizontal run to the vent terminal.

2.The vent must be insulated through the length of the horizontal run.

Common Venting System

Common venting of Category IV systems is not al- lowed.

WARNING: No substitutions of flue pipe or vent cap material are allowed. Such substitutions would jeopardize the safety and health of inhabitants.

	Certified		Maximum	Combustion Air	Air Inlet
Model	Venting	Vent Size	Equivalent	Intake Pipe	Max. Length*
	Material		Vent Length	Material	6”	8”
302AE		5”	70’		100’	N/A
402AE
		6”	Room Air	Galvanized Steel,
502AE					75’
	Category II		40’	PVC,
652AE	or IV			ABS,		100’
			Ducted
				CPVC	40’
752AE		8”	Combustion
			Air
902AE					30’	80’

* Subtract 10 ft per elbow. Max. 3 elbows.

Maximum combustion air duct length terminated at 100 equivalent ft.

Table R: Category II and IV Venting

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