MACH
®
Gas Fired Boiler
20
Conventional Vent Systems Clearances
The following termination clearance requirements are for conventional, non-direct vent installations.
•
The vent system shall terminate at least 3 ft above a forced air inlet within 10 feet horizontally.
•
The vent system shall terminate at least 4 ft below, 4 ft horizontally from or 1 ft above any door, operable window
or gravity inlet into any building. The bottom of the vent terminal shall be at least 12 in. above grade or highest
expected snow line (if applicable).
•
Through the wall terminations shall not terminate over public walkways or over an area where condensate or
vapor could create a nuisance or hazard or could be detrimental to the operation of regulators, relief valves or
other equipment.
Direct Vent (Sealed Combustion) Systems Clearances
•
The vent terminal shall be located at least 12 in. from any air opening into a building. The bottom of the vent
terminal shall be at least 12 in. above grade. Both the vent and air intake terminals must be at least 12 in. above
the highest expected snow line.
•
Through the wall terminations shall not terminate over public walkways or over an area where condensate or
vapor could create a nuisance or hazard or could be detrimental to the operation of regulators, relief valves or
other equipment.
Interior Component Clearances
All vent system components shall be installed so as to maintain the following required minimum clearances:
Combustible
Non-Combustibles
Unlisted single wall metal pipe
Do NOT Use
Do NOT Use
Single wall CPVC pipe
18 in.
As required for installation & access
UL 1738 listed Category IV vent
Per manufacturer’s listing
Per manufacturer’s listing
3.5.3.6
Flue Connection
The boiler vent should not be connected into any portion of another mechanical
draft system without consulting the vent manufacturer. The boiler shall not be connected to any part of a
vent system serving a Category I or II appliance, nor shall a Category I or II appliance be connected to
any part of the vent system serving this appliance. Improper interconnection of venting systems may
result in leakage of flue gases into occupied spaces.
NOTE!
Make sure that the weight of the vent is
not supported
by the boiler vent collar.
The collar is
not designed to support the weight of the vent.
The CPVC or manufactured vent system shall be
supported in accordance with the manufacturer’s instructions. Horizontal vent sections shall be
supported in a manner to prevent sags or low spots where condensate can collect. Structural supports
must be connected to building elements of sufficient strength to withstand the weight of the vent system
and any bending forces imposed by the venting system.