AERCO Modulex High Pressure Manual - Manual (Page 27)

INSTALLATION, OPERATION & MAINTENANCE
3-1
GENERAL INFORMATION FOR VENTING
Note: See Venting Guide GF-115-V for venting specifications and materials.
3.1 VENT PIPE CONNECTION
The Modulex boiler is approved for a Category IV vent configuration as well as
for sealed combustion installations. 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.
Maintain clearances from combustible construction for boiler, vent connector,
and steam and hot-water pipes.
3.2 GAS VENT CATEGORIES
Federal Codes have categorized gas appliances by the vented flue gas pressure and temperature.
These categories are defined as follows:
• 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 degrees F (60 degrees
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 degrees F (60 degrees 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 degrees F (60 degrees 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.
3.3 INSTALLATION AND SIZING
The AERCO Venting Guide, GF-115-V, must be consulted before any flue gas vent or air inlet piping is
designed or installed. Certified venting materials specified in GF-115-V must be used for safety and
code compliance. Because the Modulex boiler is capable of discharging low temperature exhaust
gases, the flue must be pitched back to the unit a minimum of ¼” per foot to avoid any condensate
pooling and to allow for proper drainage.
For side wall venting in Massachusetts:
• The vent termination must be located at a minimum of 4 feet above grade level.
• IMPORTANT: See pages v and vi of this manual (GF-115H) for detailed information pertaining
to side wall venting within the Commonwealth of Massachusetts.
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