Manufacturer of I.D. blowers, F.D. blowers, force draft fans, force draft blowers, blow off ventilators / fans, PVC FRP SST ventilators, squirrel cage blower fans, high pressure centrifugal ventilators, Chicago blowers, aluminum fans, stainless steel ventilators, hot air blowers, heating fans, high temperature oven ventilators, high pressure air blowers, squirrel cage blower wheels, Peerless Dayton ventilators, Sheldons blowers, New York fans NYB, TCF, Delhi fans blowers. Sales of industrial and commercial gas fired direct and indirect air handling units AHU, commercial and institutional Canadian Blower - Buffalo fan AHU air handling units and fans, roof and wall exhaust and air makeup fans, pressure blower ventilators. Industrial process Buffalo Fan A.H.U. air-handling units as well as fan / blower / ventilators from Buffalo, New York.










Tenderall Co. makes two primary gas-fired AHU types: direct gas-fired and indirect gas-fired air handlers.


A direct gas-fired AHU has a gas burner installed directly in the outside makeup-air stream. The products of combustion (carbon dioxide [CO2], carbon monoxide [CO], nitrogen dioxide [NO2]) are discharged directly into the makeup air stream and supplied to the building area.


An indirect gas-fired AHU has a sealed combustion chamber where all products of combustion are discharged through a flue to the outside environment and no products of combustion are discharged within the make-up air supplied to the building. Such airhandler also frequently is utilized for recirculating-air applications.


Though simple in principle of operation, direct gas-fired AHUs have sophisticated burner-control systems. AHUs sizes range from 1,000 cfm with a heating capacity of 80,000 Btuh to 100,000 cfm with a heating capacity of 15 million Btuh. Direct-gas-fired-AHU components usually include housings, supply fans, outside air intake hoods, intake dampers, filters and burners.


AHU housings are made of galvanized or aluminized steel. Access panels are provided to access dampers, filters, burners, and fans / motors. AHUs located outside are provided with a sloped roof and standing seam joints.


Fans typically are double-width double-inlet (DWDI) with forward-curved or backward-inclined blades. Fans can come with open drip-proof (ODP) or totally enclosed fan cooled (TEFC) motors. The most typical external static pressure in the 2- to 3-in.-wg range. Because most outside istalled air handling units can operate  below 0°F, fan motors and bearings are rated to handle lower temperatures. For applications that require supply-air temperatures higher than 110°F, the motors and fan bearings are rated for maximum design operating temperatures when placed in draw-through configurations.


Outside air intake hoods or weather hoods are designed for an installation specific location and usually provided with bird screens. Outside-air intake isolation dampers are furnished to prevent cold air from dropping through a unit into a warm building and warm air from escaping through a unit during winter months, when it is not in operation. Low-leakage parallel blade isolation dampers are most standard. The fan discharge is located at the opposite to isolation-damper position.


A filter cabinet normally has 30/30 filters in a V-bank configuration to increase filter area and reduce static-pressure drop across the filters. Higher-efficiency filters are used on application.


A burner consists of a cast-iron or aluminum pipe assembly with drilled gas orifices. The fuel-air mixing is controlled by perforated stainless-steel baffles attached to the pipe assembly. The burner can be placed in the outside airstream or in the outside / return mixed-air stream. But to prevent potentially hazardous combustion byproducts of indoor-air contaminants, the burner is placed in the outside airstream only. The required airflow across the burner must be within a specific velocity range (typically 2,500 to 3,500 fpm) for proper combustion. For variable airflow units, a modulating bypass damper or profile plate maintains the airflow velocity within the specified velocity range. Otherwise, the burner can experience inefficient operation, generate odors in the occupied spaces served, and create an un-safe increase in certain products of combustion.

LONG SERVICE LIFE: We use premium quality industrial-grade materials and additional protective coatings for external surfaces and internal components of our Air Handling Units - to withstand the specific gases flow and the installation conditions of each application, industrial and commercial / institutional.

CAPACITIES: Up to 100,000 CFM for standard construction and larger, custom made on special request.

FLEXIBILITY: Every air handling unit is designed for the specific installation and connections conditions. The AHU floor area and its cross section dimensions are adjusted for precise room available at site.

EASY INSTALLATION: Packaged compact or sectional air handler design provided with lifting arrangement and protections for easy transportation and handling / installation at site.

LOW MAINTENANCE: Service friendly design which provide large room inside cabinet, access doors, light and rigid floor ensuring accessibility to all components.

HIGH EFFICIENCY: Fans, coils, motors, humidifiers, filters, external insulation material, silencers, enclosure tightness, and other components are carefully selected and engineered for lowest energy consumption.

OPERATIONALLY SAFE: Safety devices and guards are provided in accordance to the international regulations and the customer specific requirements.

PRECISE PERFORMANCE: To match the customer capacities requirement utilizing
the computerized selection for each AHU component.

Industrial gas fired Heatcraft air handling unit airhandler

Industrial gas-fired airhandler Heatcraft ahu air-handling units

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One of the most critical components of the fan are the bearings. So naturally if the bearings are kept out of the hot airstream they are less susceptible to the effects of the high temperature, and therefore the air temperature can be higher than the limiting temperature of the bearings. Inline fans inherently have drive components in the airstream. In such cases, the unit can sometimes be designed so that cooler outside air is drawn over the drive components, providing some additional cooling. Incorporating this type of external cooling is one of the main reasons NIS-CO Fan medium pressure tube axial inline fan (TBI) can be used for high temperature exhaust applications. There are, however, some arrangements that donÕt allow for the incorporation and benefits of external cooling. For instance, fans in arrangement 3 have the wheel suspended in-between the two bearings. Consequently, one or both of the bearings will always be located in the air stream. Similarly, direct drive fans are limited by the maximum operating temperature of the motor, since the motor is located directly in the hot air stream. That is why most often high temperature exhaust fans are required to be belt driven units; typically the motor is the temperature-limiting component of the unit when it is installed in the airstream. Other than the installation location of the bearing within the fan assembly, other critical points to consider include the type of lubrication in the bearing, as well as the construction of the bearing itself. There is a seemingly endless list of lubricants available for most any application, but the appropriate lubricant can add considerable life to bearing operation. In addition, high temperature bearings can be constructed with inherent construction modifications, such as a larger grease cavity to hold more lubricant.
Another common variation to the standard fan design is the addition of insulation. The bearing mounting plate, bearing cover and belt tube are the most likely components to be insulated for a high temperature application. NIS-CO Fan automatically includes insulation for these components on all fans specified with either HT Option III or HT Option IV.

It is important to understand that emergency smoke exhaust fans are designed to operate effectively for the temperature and time limits stated as long as the power supply to the fan is not terminated. Since they are not designed to sustain higher temperatures for continuous use, exposure to the extreme high temperatures caused by a fire likely would destroy some or all parts of the fan once the time design limit has elapsed, rendering it incapable of future operation.

Fans that are built for continuous high temperature ventilation have many of the same construction features and options as those built for emergency smoke exhaust. For example, both are typically constructed of higher temperature ferrous materials, have high temperature bearings, have the motor and drive installed either out of the airstream or with some type of additional cooling capabilities, and incorporate some heat shielding or insulation. There are, however, some distinct differences between the fan designs for the two application categories. One of the most common applications for which continuous duty high temperature exhaust fans are specified is commercial kitchen ventilation.

Fans that are specified for continuous operation at higher temperatures need to be carefully selected taking into account air density corrections. Although a fan will move the same amount of air at two different temperatures, the static pressure and horsepower requirements can change drastically as the density of the air varies with changing temperatures. For example, if a fan moves 3,000 CFM at 70 F it will also move 3,000 cfm at 500 F. However, since the hotter air weighs much less than the 70¼F air, the fan will require less brake horsepower and will create less static pressure.

There are also some accessories and construction options that are incorporated into high temperature process fans to increase the limiting temperature. For example, a heat slinger can be installed on the shaft between the fan housing and the inboard bearing. A heat slinger is an aluminum disc that absorbs and dissipates some of the heat conducted along the shaft before it travels to the bearings. Many heat slingers incorporate fans that promote additional inboard bearing cooling because it circulates air with every rotation of the shaft.

Another common construction technique is the use of a heat gap. A heat gap is a physical gap between the bearing support structure and the hot fan housing. This separation slows the process of heat conduction to the bearings and drive components through the housing and support structure. An expansion bearing should be installed where the fan shaft is predicted to conduct enough heat that it could expand to a length greater than that of the structure to which it is secured. This allows for expansion of the shaft within the bearing due to the higher temperatures.

High temperature applications can be found in many different areas of the air movement and control industry. It is important to remember that one high temperature fan design is not suited to all applications.