Lochinvar 1, 000 Danger, Vertical Direct Vent Systems, Combined Combustion Air Inlet Points

sealant to ensure a proper seal at the appliance connection and the air inlet cap connection. Dryer vent or flex duct should use a screw type clamp to seal the vent to the appliance air inlet and the air inlet cap. Proper sealing of the air inlet pipe ensures that combustion air will be free of contaminants and supplied in proper volume.

When a sidewall or vertical roof top combustion air supply system is disconnected for any reason, the air inlet pipe must be resealed to ensure that combustion air will be free of contaminants and supplied in proper volume.

DANGER ￿

Failure to properly seal all joints and seams as required in the air inlet piping may result in flue gas recirculation, spillage of flue products and carbon monoxide emissions causing severe personal injury or death.

Combined Combustion Air Inlet Points

The air inlet pipes from multiple appliances can be combined to a single common connection if the common air inlet pipe has a cross sectional area equal to or larger than the total area of all air inlet pipes connected to the common air inlet pipe. {Example: two 8" (20.3 cm) air inlet pipes [50.3 in2 (324.5 cm2) area each] have a total area of 100.6 in2 (645.2 cm2) requires a 12" (30.5 cm) [113.1 in2 (729.7 cm2] common air inlet pipe.} The air inlet point for mul- tiple boiler air inlets must be provided with an exterior opening which has a free area equal to or greater than the total area of all air inlet pipes connected to the common air inlet. This exterior opening for combustion air must connect directly to the outdoors. The total length of the combined air inlet pipe must not exceed a maximum of 100 (30.5 m) equivalent feet. You must deduct the restriction in area provided by any screens, grills or louvers installed in the common air inlet point. These are common on the sidewall air inlet openings and some rooftop terminations. Screens, grills or louvers installed in the common air inlet can reduce the free area of the opening from 25% to 75% based on the materials used.

3'
12"
FIG. 20	Vertical	Direct	Vent	Installation	with	Rooftop

Combustion Air Inlet

Follow all requirements in the General Category IV Venting sections for proper installation and of venting flue products vertically to the outdoors. All other general installation requirements must be followed.

The Direct Vent system requires the installation of an additional pipe to supply combustion air from outdoors directly to the appliance. The air inlet pipe must use one of the specified materials.

The maximum installed length of the air inlet pipe from the appliance to the air inlet cap is 100 equivalent feet (30.48 m) in length. The maximum installed length of the flue pipe from the appliance to the termination cap is 100 equivalent feet (30.48 m) in length. Subtract 5 feet (1.52 m) of equivalent length for each 90° elbow installed in either the flue pipe or the air inlet pipe.

Termination point for the flue products must follow the clearance requirements in the Vertical Vent Termination sections of the Category IV Venting.

VERTICAL DIRECT VENT SYSTEMS

A Vertical Direct Vent System is installed with a Category IV flue and a separate combustion air pipe to the outdoors. The Direct Vent system terminates both the flue and air inlet in the same pressure zone. The flue outlet and combustion air intake must both terminate on the rooftop.

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