Install Instructions

42
APPENDIX B1 – ATMOSPHERIC VENTING
GENERAL WARNINGS FOR ATMOSPHERIC VENTING SYSTEMS
USE ATMOSPHERIC VENTING only with
boilers approved for atmospheric venting as
noted in the Specifications Section of this
manual.
INSPECT EXISTING CHIMNEY for obstructions
and deterioration and repair or line the chimney
prior to placing the boiler in service.
UNLINED MASONRY CONSTRUCTION is
prohibited for use as a chimney.
FIREPLACES AND FAN-ASSISTED GAS
APPLIANCES must not be vented into the same
chimney space as this boiler. Vent connectors
serving appliances vented by natural draft shall not
be connected into any portion of mechanical draft
systems operating under positive pressure.
DO NOT REDUCE THE DIAMETER of the vent
connector between the boiler and the chimney. It
must not be smaller than the outlet on the draft
hood, damper, or vent reducer supplied with the
boiler.
Exception: National Fuel Gas Code,
ANSI Z223.1/NFPA 54, and Natural Gas
and Propane Installation Code, CAN/
CSA B149.1, allow vent downsizing when
vent size determined by their Vent Sizing
Tables is smaller than draft hood outlet/
vent damper. These codes require all of the
following:
(a) Total vent height (H) is at least 10 ft (3
m);
(b) Vent not reduced more than one table
size; and
(c) Draft hood outlet/vent damper
is greater than 4 in. (102 mm) in
diameter (IN3I cannot use smaller
vent size).
UNLISTED VENT DAMPERS AND
OBSTRUCTIONS in the vent pipe are prohibited.
THE VENT DAMPER supplied with the boiler
shall not be used to block the vent of any other
appliance.