furnace is approximately 60 to 75 percent higher
than the first cost of a conventional type furnace.
**************************************************************************
Gas-fired furnace shall be the [conventional] [high efficiency, condensing]
type in accordance with ANSI Z21.47. Furnace design shall be certified by
the AMERICAN GAS ASSOCIATION LABORATORIES (AGA). Furnace shall have a
minimum certified Annual Fuel Utilization Efficiency (AFUE) of not less
than [78] [80] [90] percent.
2.1.2
Oil-Fired Unit
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NOTE: Furnace with a capacity less than 65.9 kW
(225 MBtuh) require a minimum AFUE of 78 percent.
Furnace with a capacity greater than 65.9 kW (225
MBtuh) require a minimum AFUE of 81 percent.
**************************************************************************
Oil-fired furnace shall be in accordance with UL 727 and have a minimum
certified Annual Fuel Utilization Efficiency (AFUE) of [78] [81] percent.
2.2
FURNACE COMPONENTS
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NOTE: Delete any of the following paragraphs which
are inapplicable to a specific job (i.e. oil-fired
components or gas-fired components). For example,
oil-fired components are inapplicable to high
efficiency furnaces and should be deleted when high
efficiency furnaces are specified.
**************************************************************************
2.2.1
Oil-Burning Components
The equipment shall include the oil burner motor, ignition equipment safety
devices, and accessories necessary for a full automatic system that
conforms to UL 296. Oil-fired units equipped with programming controls
shall be furnished with low oil-pressure switches in the fuel supply
piping. Oil-fired units not equipped with programming controls shall be
equipped with a delayed opening or shutoff valve. The valve shall
automatically delay delivery of oil to the burner until such time as the
combustion air fan and, when applicable, the induced draft fan are operated
at rated speed.
2.2.2
Gas-Burning Components
Gas-burning equipment shall include the gas burners, ignition equipment,
gas-control valve, gas piping, gas-pressure regulating valve, when
applicable, and accessories necessary for a fully automatic system that is
listed in CSA Directory. Gas-fired units equipped with programming
controls shall be furnished both with high and with low gas supply pressure
switches in the fuel supply piping.
2.2.3
Ignition Systems
2.2.3.1
Gas-Fired Units
Ignition systems shall be of the direct spark, hot surface, or interrupted
SECTION 15566A
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