Trane Gas Unit Heaters Katalog
UH-PRC002-EN
7
Application Considerations
General
Propeller fan unit heaters and centrifugal fan unit heaters are designed for use in space heating
applications. The units are typically used in areas with high ceilings, and are exposed in the space
to be heated. Unit heaters offer low installed cost, and are able to heat large volume areas without
requiring extensive duct systems.
applications. The units are typically used in areas with high ceilings, and are exposed in the space
to be heated. Unit heaters offer low installed cost, and are able to heat large volume areas without
requiring extensive duct systems.
Duct furnaces are designed for use in ducted applications with a separate air handling device such
as a horizontal blower assembly. By utilizing a separate air source, greater application flexibility in
airflow delivery can be obtained. Multiple duct furnaces can be used with an air handling unit to
provide zone heating.
as a horizontal blower assembly. By utilizing a separate air source, greater application flexibility in
airflow delivery can be obtained. Multiple duct furnaces can be used with an air handling unit to
provide zone heating.
Note: When installing duct furnaces in parallel or in series, minimum clearance requirements
must be considered. This is required for serviceability of the gas valve and the high limit.
“All duct furnaces are approved in blow-thru applications only.”
“All duct furnaces are approved in blow-thru applications only.”
All duct furnaces are AGA approved upstream or downstream of the cooling coil. Recommend
optional field installed drain pan when installed on the downstream side of the cooling coil.
optional field installed drain pan when installed on the downstream side of the cooling coil.
Note: Downstream denotes cooling coil ahead of the fan section.
When used in conjunction with filters, cooling coils and an air handler, the duct furnace can become
part of a built-up heating and cooling system.
part of a built-up heating and cooling system.
Gas Heating Value
The majority of gas heating units are installed in applications where natural gas is readily available.
In areas where natural gas is not available, Trane units may be ordered directly from the factory
for use on LP (propane) gas.
In areas where natural gas is not available, Trane units may be ordered directly from the factory
for use on LP (propane) gas.
Gas heat content varies by fuel type and location. The standard gross heating value for natural gas
is 1,000 Btu per cubic foot, and for propane, 2,500 Btu per cubic foot. Significant variations from
these standard values should be taken into consideration in equipment selections. To account for
variations in the gross heating value of the fuel, adjust the total heat input required and select the
unit on the basis of the adjusted load using the following formula:
is 1,000 Btu per cubic foot, and for propane, 2,500 Btu per cubic foot. Significant variations from
these standard values should be taken into consideration in equipment selections. To account for
variations in the gross heating value of the fuel, adjust the total heat input required and select the
unit on the basis of the adjusted load using the following formula:
Low Temperature Rise
Trane recommends against the setup of a unit which will result in a temperature rise of less than
30°F. With such low temperature rises, the flue gases passing through the heat exchanger are
cooled to condensate before reaching the flue outlet. This condensate is corrosive and will result
in shortened heat exchanger life.
30°F. With such low temperature rises, the flue gases passing through the heat exchanger are
cooled to condensate before reaching the flue outlet. This condensate is corrosive and will result
in shortened heat exchanger life.
Air Density
Catalog performance data is based on elevations up to 2,000 feet above sea level. Above 2,000 feet
the unit’s heating capacity must be derated four percent for each 1,000 feet above sea level, and
the unit’s heating capacity must be derated four percent for each 1,000 feet above sea level, and
Adjusted load = Calculated load x gross heat value (Btu/ft
3
)
Actual gross heat value (Btu/ft
3
)