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NORA Oilheat Technicians Manual

Chapter 6 Draft and Venting 24 VAC Relay coil Chapter 6—Draft and Venting 6-17 The following guidelines are often required by code: • Direct vent systems can be placed on any wall, but if possible they should not be located on the wall facing the prevailing wind (the prevailing wind generally comes from the north and the west; if possible, locate on the south or east side of the building). • The vent terminal must be at least one foot above grade level, and three feet away from any inside corner. It may need to be higher in areas with snowfall. • The vent terminal shall not be less than three feet above any forced air inlet into the building that is located within 10 feet of the terminal. • The vent terminal shall not be less than four feet below, four feet horizontally, or one foot above any door, window, or gravity inlet into any building. The vent shall not be installed in a window well. • The vent terminal shall not be less than two feet from an adjacent building. • The vent terminal shall not be less than seven feet above grade when located adjacent to public walkways. • The vent terminal shall be located so that flue gases are not directed to jeopardize people, overheat combustible structures or materials, or enter buildings. • All positive pressure joints in the vent system (all joints in direct-vent, all joints on the exhaust side of the power-venter) are to be sealed with Permatex #81164 high temperature sealer or equivalent to prevent leakage of the products of combustion into the building. We are referring here to both the joints between pieces of pipe and the slip joints on elbows. • The minimum distance to combustible materials from any single wall, vent system component is 18 inches. • The vent termination should not be mounted directly above or within three feet horizontally from a gas meter, electric meter or air conditioning condenser. Power-venting Power-venting is an economical alternative to conventional chimney venting. Power-venters use a motor and fan to vent the products of combustion from the appliance to the outdoors. Power-venters are designed with the fan located either outdoors or indoors just before the outside wall, as in Figure 6-16. This insures that combustion gases in the flue pipe are always under negative pressure, so if there are any leaks, air will leak into the pipe and the combustion gases will not spill into the building. The flue gases are discharged through a double wall vent termination piece and an Figure 6-16: Power venter, indoor fan Barometric Damper 3-Wire Conductor (Low Voltage) Measure Draft Here Furnace Power Venter Approved Vent Hood


NORA Oilheat Technicians Manual
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