Hydronic Heating Boilers and Domestic Water Heaters
INSTALLATION
Continued
TABLE - B
Flue Pipe Sizes
Input Flue
Btu/hr Size
495,000 6"
645,000 8"
745,000 8"
985,000 10"
1,255,000 12"
1,435,000 12"
1,795,000 14"
2,065,000 14"
Vent System Options
This unit has two venting options.
1. Conventional Negative Draft Venting
This option uses a vertical rooftop flue termination. Combustion air is supplied from the mechanical room. See page 13 for detailed information.
2. Outdoor Installation Venting
This option uses the installation of special air inlet and vent caps on the unit. See page 13 for venting details.
All units are shipped from the factory equipped for conventional negative draft venting. All other optional vent systems require the installation of specific vent kits and venting materials. The following is a detailed explanation of the installation requirements for each venting system, components used and part numbers of vent kits for each model.
Barometric Damper Location
Any venting system option that requires a barometric damper must adhere to the following directions for optimum performance.
The preferred location for the barometric damper is in a tee or collar installed in the vertical pipe rising from the unit’s flue outlet. The barometric damper MUST NOT be installed in a bull head tee installed on the unit’s flue outlet. The tee or collar containing the barometric damper should be approximately three feet vertically above the connection to the unit’s flue outlet. This location ensures that any positive velocity pressure from the unit’s internal combustion fan is dissipated and the flue products are rising due to buoyancy generated from the temperature of the flue products. Adjust weights on damper to ensure that draft is maintained within the specified ranges.
TABLE–C
Minimum Recommended Combustion Air Supply To Boiler Room
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| Combustion Air Source |
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Boiler Input | Outside Air*/2 Openings | Outside Air*/1 Opening | Inside Air/2 Openings | ||||
495,000 | 125 in2 (806 cm2) | 167 in2 | (1077 cm2) | 500 in2 | (3226 cm2) | ||
645,000 | 163 in2 (1052 cm2) | 217 in2 | (1400 cm2) | 650 in2 | (4194 cm2) | ||
745,000 | 188 in2 (1213 cm2) | 250 in2 | (1613 cm2) | 750 in2 | (4839 cm2) | ||
985,000 | 248 in2 (1,600cm2) | 330 in2 (2,129cm2) | 990 in2 |
| (6,388cm2) | ||
1,255,000 | 315 in2 | (2,032cm2) | 420 in2 | (2,710cm2) | 1260 in2 |
| (8,130cm2) |
1,435,000 | 360 in2 | (2,323cm2) | 480 in2 | (3,097cm2) | 1440 in2 |
| (9,291cm2) |
1,795,000 | 450 in2 | (2,903cm2) | 600 in2 | (3,871cm2) | 1800 in2 (11,614cm2) | ||
2,065,000 | 518 in2 | (3,342cm2) | 690 in2 | (4,452cm2) | 2070 in2 | (13,356cm2) | |
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*Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a duct, the net free area of each of the two openings must have twice (2 times) the free area required for Outside Air/2 Openings. The above requirements are for the boiler only, additional gas fired units in the boiler room will require an increase in the net free area to supply adequate combustion air for all units. Combustion air requirements are based on the latest edition of the National Fuel Gas Code, ANSI Z223.1, in Canada refer to
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