Chapter 3: Vent System; Vent Installation - Watts Aerco Modulex EXT Series Technical Application Manual

Modulex EXT Vent and Combustion Air Application Guide

CHAPTER 3: VENT SYSTEM

Correct boiler venting is crucial for proper operation. Being a condensing boiler, combustion gases are
discharged at a very low temperature. It is therefore necessary for the venting system to be
impermeable to combustion products and condensate and to be made of corrosion resistant
materials. Typical Category IV venting and sealed combustion illustrations are shown in Figure 5
through 9. The various funnel joints shall be well sealed and/or equipped with suitable gaskets, in
order to avoid any condensate drain and/or air intake. Ensure that the boiler vent's section and height
conform to national and local regulations (see Section 1.1 in this guide).
For boilers designed for connection to gas vents or chimneys, vent installations shall be in accordance
with Part 7, Venting of Equipment, of the National Fuel Gas Code, ANSI Z223.1, or Section 7, Venting
Systems and Air Supply for Appliances, of the CAN/CGA B149, Installation Codes, or applicable
provisions of the local building codes.
The vent system for the Modulex boilers must be installed in accordance with AERCO's installation
CAUTION!
For Category IV Boilers, the vents must be installed to prevent accumulation of condensate, and
have means provided for drainage of condensate.

3.1. VENT INSTALLATION

•
The boilers covered in this section are design-certified as Category IV for venting, only when
they are installed with manufacturer specified vent system components and installation
practices.
•
Install supplied vent pipe starter piece at the boiler vent connector and work toward the vent or
rain cap. To attach the exhaust connector to the flue collector, use the screws and the gasket
supplied inside the plastic bag. Use a 14mm socket wrench with at least a 12 inche (300 mm)
extension. See Figures 11 and 12.
•
Vent pipe fittings and connectors serving appliances vented by natural draft shall not be
connected into any portion of mechanical draft systems operating under positive pressure.
•
Horizontal runs
(21 mm/m) from the boiler to the vent termination.
•
Horizontal portions of the venting system shall be supported to prevent dips or sags where
condensate could collect.
•
Rigidly support vent pipe every 5 feet and at the elbows. Plumber straps may be used.
•
ALL vent pipe and fittings must be installed with appropriate air space clearances to
combustibles. These air space clearances apply to indoor or outdoor vents, whether they are
open, enclosed, horizontal or vertical or pass through floors, walls, roofs, or framed spaces.
The appropriate air space clearances should be observed between joists, studs, sub floors,
plywood, drywall, or plaster enclosures, insulated sheathing, rafters, roofing, and any other
combustible material. The minimum air space clearance also applies to electrical wires and
any kind of building insulation. For horizontal runs, keep 4 inch and 6 inch vent piping from
any contact with any combustible material, electric wires, and building materials.
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09/25/2017
shall be sloping upwards
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Phone: 800-526-0288
not less than 1/4 inch per foot
TAG-0054-0F
GF-136-V