Direct Gas Heating Systems - Page 2

The basic SBD system is designed to heated 100% outside air into a building to replace that amount of air which is exhausted. It is often desirable to bring in an excess of make-up air over that exhausted to insure a positive pressure in the area. This eliminates the many problems of negative pressure.

Normally the exhaust system is interlocked with the SBD make -up air system so that the units are in operation at the same time.

During operation of the SBD, air flow is continuous with discharge of air temperature regulated by modulating controls. The air temperature controls can either be nonelectric modulating gas valves, modulating gas butterfly valves or electronic gas flame modulation. Each of these control systems allow the burner to operate at any point on its turndown range to provide a constant heater air discharge temperature.

The SBD system, in addition to its primary function as a make -up air heater, can also serve as a space heater. In many industrial and commercial applications it is practical and economically sound to use a single source of space heat and make -up air. In these instance, over -riding space air temperature controls are added to the basic discharge air temperature control system.

SBDF -- DUCT FURNACE

The SBDF system consists of the basic SBD direct gas-fired burner section without a blower section. The burner section is applied as a duct furnace in field - fabricated ventilation systems.

All control and gas manifold options listed for the SBD systems are available with the SBDF direct gas - fired duct furnaces. Such accessories as filters, dampers and intake hoods can also be furnished with the furnaces.

To avoid stratifications of the heated make -up air, the SBDF duct furnace should be located on the suction side of the blower to take advantage of the mixing effect of the fans.

While the performance data of the SBDF duct  furnace is the same as that listed for the SBD and SBDR systems, a smaller size duct furnace may often be used with a field-fabricated ventilation application.The burner section size is no longer predicated on the physical size of the SBD blower section. Consult your local Hastings sales representative for selection and dimensional information.