A.O. Smith HYB-90N If using 3 inch vent pipe, Termination Elbow, Elbow Strap, ELBOW 6 in 15cm MIN

TERMINATION ELBOW

NOTE: VENT PIPE MUST BE SUPPORTED EVERY 4 ft. (1.2m). TO PREVENT VIBRATION, USE ISOLATION PADS WHEN ATTACHING STRAPS TO FLOOR JOISTS, WALLS OR CEILINGS.

45°

ELBOW

STRAP

90°

RODENT SCREEN (INSTALL INTO ELBOW)

GROUND LEVEL OR

MAXIMUM SNOW

LINE*

Example for calculating equivalent feet. Section “A” . . . . 0.5 ft. . . (0.15m)

90° elbow . . . . . 7.0 ft. . . (2.13m) Section B . . . . . 1.0 ft. . . (0.31m) 45° elbow . . . . . 4.0 ft. . . (1.21m) Section C . . . . . 1.5 ft. . . (0.46m) 45° elbow . . . . . 4.0 ft. . . (1.21m) Section D . . . . . 15.0 ft. . (4.57m) Total Equivalent 33.0 ft. . (10.04m)

Based on this example use the (fully open) rodent screen for vent length greater than 20 equivalent ft. (6.1 equivalent metres).

Vent piping must slope up from heater to termination a minimum of 1/8 in. (0.3cm) rise per 4 ft. (1.2m) of vent piping

ELBOW

6in.

(15cm)

MIN.

FIGURE 21

If using 3 inch vent pipe:

Install the rubber reducing coupling (2 in. to 3 in.) and gear clamps (supplied) at the end of the section of vent pipe installed on the heater. Continue building the vent system, or connect the existing vent system to the coupling. The total system must not exceed the equivalent pipe lengths discussed above where each (long radius) elbow is equal to 5 ft. (1.5m) of 3 in. diameter straight vent pipe. The elbow and rodent screen supplied in the vent kit must be used as the vent termination.

NOTE: This unit can be vented with PVC pipe materials (DWV ASTM-D2665; Schedule 40, 80, 120 ASTM- D1785; or SDR Series ASTM-D2241), CPVC pipe materials (CPVC41 ASTM-D2846; Schedule 40, 80 ASTM-F441; or SDR Series ASTM-F442), ABS pipe materials (Schedule 40 DWV ASTM-D2661). The fittings, other than the TERMINATION should be equivalent to PVC-DWV fittings meeting ASTM D-2665 (Use CPVC fittings, ASTM F-438 for CPVC pipe and ABS fittings, ASTM D-2661/3311 for ABS pipe). If CPVC or ABS pipe and fittings are used, then proper cement must be used for all joints, including joining the pipe to Termination (PVC Material). If local codes do not allow the use of the PVC termination when a material other than PVC is used for venting, then an equivalent fitting of that material may be substituted if the screen in the PVC terminal is removed and inserted into the new fitting.

This water heater is supplied with a 45 degree termination elbow that is a special fitting that must be used with the appliance.

PVC Materials should use ASTM D-2564 Grade Cement; CPVC Materials should use ASTM F-493 Grade Cement and ABS Materials should use ASTM D-2235 Grade Cement.

If the water heater is being installed as a replacement for an existing power vented heater in pre-existing venting, a thorough inspection of existing venting system must be performed prior to any installation work. Verify that correct material as detailed above has been used, and that the minimum or maximum vent lengths and terminal location as detailed in this manual have been met. Carefully inspect the entire venting system for any signs of cracks or fractures, particularly at joints between elbows and other fittings and straight runs of vent pipe. Check system for signs of sagging or other stresses in joints as a result of misalignment of any components in the system. If any of these conditions are found, they must be corrected in accordance with the venting instructions in this manual before completing installation and putting the water heater into service.

NOTE: (A.) For water heaters in locations with high ambient temperatures (above 100°F (38°C)) it is recommended that CPVC or ABS pipe and fittings be used. (B.) A 22.5 degree elbow (2 in. vent pipe) or a 45 degree elbow (3 in. vent pipe) with an installed screen VENT TERMINAL must be used in all cases.

4.There will be some installations where condensate will be formed in the horizontal runs of the vent system. This condensate will run into the condensate trap. The water heater is shipped with a condensate tube that attaches to the condensate trap. No other tee or fitting is required.

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