Hayward Universal H-Series Low NOx Service/Installation: H150FDN H200FDN H25 - Page 15

15 VERTICAL VENTING - NEGATIVE PRESSURE Vent Sizing Size the vent pipe according to the venting tables in the National Fuel Gas Code (ANSI Z223.1/NFPA 54) for a Category I gas appliance using single-wall or double-wall (Type B) gas vent. Vent pipe diameter should not be less than the size of the vent pipe adapter on the heater (see Table 5). The maximum vent height cannot exceed 50 ft. The total lateral (horizontal) length cannot exceed 1/2 of the total vent height. The system may have up to 3 90-degree elbows maximum. Single-wall vent may be used in conditioned spaces only. Clearance to combustible materials for single-wall vent is 9 inches. Double-wall (Type B) vent must be used in nonconditioned spaces. Table 5 Vent Pipe Diameters for Negative-Pressure Indoor Vent Kits Indoor Vent Kit Part Number UHXNEGVT11501 Heater Model H150FD Vent Pipe Diameter 6 inch UHXNEGVT12001 H200FD 6 inch UHXNEGVT12501 H250FD 6 inch UHXNEGVT13001 H300FD 8 inch UHXNEGVT13501 H350FD 8 inch UHXNEGVT14001 H400FD 8 inch Vent Termination Vent extending through a roof or wall must be listed double-wall (Type B) vent, and pass through an approved roof jack, or roof thimble. A listed vent cap must be used. Gas vents that are spaced less than 8 ft horizontally from a vertical wall or similar obstruction shall terminate not less than 2 ft above any portion of a building within 10 ft. Gas vents that are spaced 8 ft or more horizontally from a vertical wall or similar obstruction shall terminate above the roof a distance H based on the roof pitch. Using the roof pitch, find the minimum value of H using Figure 3 and Table 6 Figure 3 Minimum Height from Roof for Vent Cap Table 6 Height Requirements for Vent Caps (see Figure 3) Roof Slope Min. Height H from Roof to Lowest Discharge Opening Listed Lowest discharge opening cap Flat to 6/12 Over 6/12 to 7/12 Over 7/12 to 8/12 1.0 ft 1.25 ft 1.5 ft Listed gas vent x 12 Over 8/12 to 9/12 Over 9/12 to 10/12 Over 10/12 to 11/12 2.0 ft 2.5 ft 3.25 ft Roof pitch is x/12 Over 11/12 to 12/12 4.0 ft Over 12/12 to 14/12 5.0 ft Over 14/12 to 16/12 6.0 ft H (minimum)Minimum height from roof Over 16/12 to 18/12 7.0 ft to lowest discharge opening Over 18/12 to 20/12 7.5 ft Over 20/12 to 21/12 8.0 ft USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Pomona, CA Clemmons, NC Nashville, TN Tel: 908-351-5400 www.haywardpool.com