Vent Elbows; Barometric Damper; Barometric Damper Location; Flue Connection - Patterson-Kelley Thermific Installation & Owner's Manual

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Thermific Gas-Fired Boiler
The venting system and the horizontal portions of the
venting system shall be supported to prevent sagging.
Consult your local vent supplier for correct vent sizing
and structural support requirements. Vent diameter is
dictated by the length and height of horizontal and ver-
tical portions of the vent installation and the materials
of construction. Correct sizing should provide a
slightly negative pressure (less than 0.1 inches of wa-
ter column) at the boiler flue outlet with a stack tem-
perature of 280º F.

3.6.1 Vent Elbows

The turn from horizontal to vertical should be made
with two 45º ells or with one long radius 90º ell for
best operation. Do not use "short radius" ells.

3.6.2 Barometric Damper

This boiler is certified for operation without a baro-
metric damper. However, some venting installations
may require a barometric damper for smooth opera-
tion. A barometric damper is supplied with each
boiler, and when used, should be installed according to
the following guidelines.

3.6.3 Barometric Damper Location

Boiler
1. We recommend that the barometric damper be
located immediately after the flue connector for
best operation. Consult vent supplier for specific
installation requirements.
Barometric
Damper
Correct Damper Location
Page 8
2. The damper may be located in either side of the
horizontal section of stack.
3. In a multiple boiler installation, one barometric
damper must be installed with each boiler.
Be sure that the damper is mounted horizontally (never
vertically). Be sure to remove all three red stops from
the damper before start-up. The damper door should
swing freely. Carefully follow all the instructions pro-
vided with the barometric damper.
Boiler
WARNING!
To avoid spillage into the boiler room of dangerous
flue gas containing carbon monoxide, the opening in
the damper (draft control gate) must never face
against the flow of flue gas.

3.6.4 Flue Connection

The connection from the boiler to the vent should be
as direct as possible and the upward slope of any hori-
zontal breaching should be at least 1/4 inch per linear
foot. This boiler should not be connected into any por-
tion of a mechanical draft system operating under
positive pressure. Provisions must be made for sup-
ports to prevent contact of the vent with combustible
surfaces.
Note: If the vent is erected directly behind the boiler,
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. Structural support and
spacing from combustible surfaces must be in accor-
dance with the vent manufacturer's requirements.
Installation
Barometric
Damper,
(incorrect
locations)
Incorrect Damper Locations