10
the vent pipe connector shall not exceed 10 feet. The chimney connector shall be installed so as to minimize
the number of elbows and to avoid sharp turns or other construction features that would create excessive
resistance to the flow of flue gasses. Tees may be used in a straight section in conjunction with a barometric
draft regulator; however, they must not be used for a 90° turn. No device that will obstruct the free flow of
flue gasses shall be installed in the chimney connector. This does not exclude the use of devices specifically
designed for the use in chimney connectors such as automatic dampers. The vent pipe should be joined
with metal screws and supported by straps. A thimble should be used to connect the vent connector pipe to
the chimney so the pipe may be readily removed in case of inspection or replacement.
No chimney connector shall pass through any floor or ceiling. The vent connector pipe must not pass
through a combustible wall or partition unless they are guarded at the point of passage by a ventilated metal
thimble not less than 12 inches larger in diameter than the connector, on metal or fireclay thimbles adequate
protection is provided at the passageway. An acceptable passageway could be either an approved, ventilated
metal thimble which is at least 12 inches larger in diameter than the vent connector pipe, or brick work
which is at least 8 inches thick constructed into the wall and surrounding the vent connector
Clearances from combustible materials or materials shall be in accordance with the clearances given. The
vent connector pipe should extend only to (and not beyond) the inside wall of the chimney. A thimble
should be used to connect the vent connector pipe to the chimney so that the vent connector pipe may be
readily removed in case of inspection or replacement.
Connection to the chimney must be made above the bottom of the chimney to avoid blockage. Vent piping
should extend just into the chimney far enough to expel flue gasses. Inserting the vent piping too far into
the chimney will cause undue obstruction. Use a thimble or a slip joint where vent pipe enters the chimney
to allow easy removal for cleaning.
If a draft regulator is required in the vent piping; it should be located at least 24 inches from the boiler if
possible in either a horizontal or vertical section of the vent pipe. The draft regulator must be installed in the
same room as the boiler and in such a manner that there is no difference in pressure between the air in the
vicinity to the regulator and the combustion air supply. Ensure that the barometric damper is accessible for
adjustment.
A Field controls type MG-1 double acting draft control and a GSK-3 thermal safety spill switch are
provided and must be installed with the gas burner. Refer to the manufacturers installation and
operation instructions for proper installation.
With the burner operating, use a draft gauge to adjust the regulator to the proper setting (see instructions
enclosed with draft gauge to adjust the regulator to the proper setting). When the burner air supply and draft
are properly adjusted, the draft in the flue should be a negative .02" W.C. to negative .04” W.C.
Two or more appliances each equipped with a safety control may be permitted to be connected to one
common chimney if sufficient draft is available for the safe simultaneous removal of all products of
combustion.
If two or more openings are provided into one chimney, they shall be at different levels on the same story of
the building, with the smaller appliance entering at the highest possible level consistent with clearances to
combustible materials.
Two or more connectors shall not be joined together unless the common connector, manifold and chimney
are properly sized. Adequate draft must be available to safely remove all products of combustion
simultaneously without leakage, or back flow.
