Bosch Appliances GWH-345/450-ESR-N manual Vent terminations, Interior masonry chimneys

Installation instructions

3.6.5Vertical terminations

Caution: Failure to install a condensate drain may result in damage not covered by the manufacturer's warranty. See chapter 3.6.3. An approved vent terminator must be used. See Table 5 for known approved vertical vent terminations.

Horizontal runs

Any gas vent section that is greater than 45 degrees from the vertical is considered horizontal. Horizontal sections must slope upwards from heater at least ¼ inch for every foot of its horizontal length and be properly supported. Under no circumstances should the exhaust vent pipe pitch downward away from heater. Pitch the termination to the outside 1/4" per foot to prevent rain water from entering the pipe.

Vent terminations

The exhaust vent must terminate above the roof surface with an approved vent cap not less than 2 feet (0.6 m) above the highest point where it passes through the roof and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction within 10 feet (3.1m). See Fig. 20 and Table 9.

Fig. 20 Vertical vent termination clearances

GAS VENT TERMINATIONS FOR LISTED VENT

CAPS

Roof pitch	H (min.)	meters
	feet
Flat to 6/12	1.0	0.30
6/12 to 7/12	1.25	0.38
Over 7/12 to 8/12	1.5	0.46
Over 8/12 to 9/12	2.0	0.61
Over 9/12 to 10/12	2.5	0.76
Over 10/12 to 11/12	3.25	0.99
Over 11/12 to 12/12	4.0	1.22

Table 9 Termination heights at various roof pitches

Over 12/12 to 14/12	5.0	1.52
Over 14/12 to 16/12	6.0	1.83
Over 16/12 to 18/12	7.0	2.13
Over 18/12 to 20/12	7.5	2.27
Over 20/12 to 21/12	8.0	2.44

Table 9 Termination heights at various roof pitches

Interior masonry chimneys

The single wall stainless steel exhaust vent pipe must be permanently mounted inside the masonry chimney. The masonry chimney may have to be tile or metal lined before the insertion of the gas vent pipe; check local codes for clarification.

You may not vent any other fuel burning appliances into any free space remaining in the chimney. The vent terminator must extend at least 3 feet (0.9 m) above where the chimney meets the roofline and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction within 10 feet (3.1 m). The top of the chimney must be sealed to prevent rain water or other elements from entering the chimney.

Exterior Masonry Chimney

Refer to the National Fuel Gas Code and consult a local venting HVAC contractor. Not recommended in cold climates.

3.6.6Horizontal terminations

Warning: Pitch the last horizontal pipe and the termination to the outside 1/4" per foot to prevent rain water from entering the pipe.

An approved vent terminator must be used. See Table 5 for known approved horizontal vent terminations. Install a condensate drain if the total straight vent length is greater than 5 feet or if the exhaust vent pipe passes through an unconditioned space.

The exhaust termination tee must project out a minimum of 10" and maximum of 16” on center from the wall thimble.

Fig. 21 and table 10 show the required clearances for the vent termination. Follow local codes if more stringent.

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