Gas Vent Catagories; Certified Venting Materials For Flue Pipe Systems - Watts Aerco Modulex EXT Series Technical Application Manual

Modulex EXT Vent and Combustion Air Application Guide

1.2. GAS VENT CATAGORIES

WARNING!
The Modulex boiler is approved for a Category IV vent configuration as well as for sealed
combustion installations. Make provisions for combustion and ventilation air in accordance with
Section 5.3, (Air for Combustion and Ventilation) of the National Fuel Gas Code - ANSI Z223.1, or
Sections 7.2, 7.3, or 7.4 of CAN/CGA B149, Installation Codes, or applicable provisions of the local
building codes.
Federal Codes have categorized gas appliances by the vented flue gas pressure and temperature:
•
Category I, being a gas appliance that operates with a non-positive vent (or natural drafted vent)
connector with a flue gas pressure and temperature at least 140°F (60°C) above its dew point.
•
Category II, being a gas appliance that operates with a non-positive vent (or natural drafted vent)
connector with a flue gas pressure and temperature less than 140°F (60°C) above its dew point.
•
Category III, being a gas appliance that operates with a positive vent (fan forced vent) connector
with a flue gas pressure and temperature at least 140°F (60°C) above its dew point.
•
Category IV, being a gas appliance that operates with a positive vent (fan forced vent) connector
with a flue gas pressure and temperature less than 140°F (60°C) above its dew point.
•
Direct Vent, a gas appliance is constructed and installed so that all air for combustion is derived
directly from the outdoors and all flue gases are discharged to the outdoors.

1.3. CERTIFIED VENTING MATERIALS FOR FLUE PIPE SYSTEMS

Acceptable materials and manufacturers for flue vent pipe systems are listed below in Option #1 –
Option #4.
WARNING!
The Vent Pipe Systems below are used for venting gas burning Category IV appliances. Do not
use these vent pipe systems for venting appliances burning fuels such as wood, coal, oil or
kerosene.
Maintain clearances from combustible construction for boiler, vent connector, and steam and hot-
water pipes.
Do not use these vent pipe systems for incinerators of any kind.
Do not vent Modulex systems using the same vent piping as being used for either Benchmark or
KC boilers.
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09/25/2017
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Phone: 800-526-0288
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