Venting Instructions - A.O. Smith T-H3S-DV Installation Manual And Owner's Manual

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Service manual (104 pages)

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Table of Contents

For the 240 Indoor (T-H3J-DV), 340 Indoor (T-H3S-DV) and 540 Indoor (T-H3-DV) models

• Improper venting of this appliance can result in excessive levels of carbon

monoxide which can result in severe personal injury or death.

• Improper installation can cause nausea or asphyxiation, severe injury or death

DANGER

from carbon monoxide and flue gases poisoning. Improper installation will

void product warranty.

When installing the vent system, all applicable national and local codes must be

followed. If you install thimbles, fire stops or other protective devices and they

penetrate any combustible or noncombustible construction, be sure to follow all

CAUTION

applicable national and local codes.

The Indoor models must be vented in accordance with the section "Venting of Equipment" of the latest

edition of the National Fuel Gas Code: ANSI Z223.1/NFPA 54 in the United States and/or Section 7 of the

CAN/CSA B149.1 Natural Gas and Propane Installation Code in Canada, as well as applicable local building

codes.

The use of venting materials approved for Category III/IV appliances is recommended whenever possible.

However, the Indoor models may also be vented with plastic pipe materials such as ABS, PVC, CPVC, or

polypropylene. For details, please refer to the Exhaust Vent (ABS, PVC, CPVC, or Polypropylene Vent)

Section on p. 15. Vent installations in Canada which utilize plastic vent systems must use venting that

complies with ULC S636.

General rules for venting water heaters are:

• Place the water heater as close as possible to the vent termination.

• The vent collar of the water heater must be fastened directly to an unobstructed vent pipe.

• Do not weld the vent pipe to the water heater's vent collar.

• Do not cut the vent collar of the unit.

• The vent must be easily removable from the top of the water heater for normal service and

inspection of the unit.

• The water heater vent must not be connected to any other gas appliance or vent stack except an

approved common-venting system. (Refer to p. 20 and 21.)

• Avoid using an oversized vent pipe or using extremely long runs of the pipe unless it is part of an

approved common vent system.

• For rooftop venting, a rain cap or other form of termination that prevents rain water from

entering into the water heater must be installed.

• Do not terminate vent into a chimney. If the vent must go through the chimney, the vent must

run all the way through the chimney with approved vent pipe.

General rules for vent terminations:

• Avoid locating the water heater vent termination near any air intake devices. These fans can

pick up the exhaust flue products from the water heater and return them to the building. This

can create a health hazard.

• Locate the vent termination so that it cannot be blocked by any debris, at any time. Most codes

require that the termination be at least 12 in. (305 mm) above grade, but the installer may

determine if it should be higher depending on the job site condition and applicable codes.

• A proper sidewall termination is recommended when the water heater is vented through a

sidewall.

• Regarding the clearances from the exhaust termination to the air inlet or opening, refer to p. 22

to 24.

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