Closed Circuit Coolers

eco-ATWB-H Closed Circuit Cooler

eco-ATWB-H Closed Circuit Cooler

The eco-ATWB-H is an induced draft, counterflow design closed circuit cooler with a CTI Certified capacity range of 850 to 16700 MBH (250 to 4895 kW). Standard construction includes the patented, high efficiency  EVAPCO Ellipti-fin Coil, EVAPCO’s new ARID fin Pak™ dry coil, and G-235 (Z-725 Europe) galvanized steel casing and basin. Type 304 or 316 stainless steel construction is available for the basin or the entire unit.



  • Continuous water savings, even when the spray pump is energized
  • Highest dry bulb switchover temperatures
  • Plume abatement
  • Plume elimination

The NEW eco-ATWB-H Hybrid line of closed circuit coolers was designed with the purpose of providing maximum water savings, higher dry bulb switchover temperatures, while achieving plume abatement or elimination. 

The eco-ATWB-H is provided with EVAPCO’s new ARID fin Pak™ dry coil. Utilizing stainless steel tubes and aluminum manganese fins, the ARID fin Pak™ maximizes the total surface area available for sensible heat transfer, which results in maximum water savings and higher dry bulb switchover temperatures. Additionally, the eco-ATWB-H is provided with the highly efficient Ellipti-fin® coil in series with the ARID fin Pak™, achieving both latent and sensible cooling simultaneously. Located in the discharge airstream, the ARID fin Pak™ heats the saturated discharge air, abating or eliminating the plume. Because the coils are in series, a significant portion of the heat load will always be dissipated through the dry cooling coil, saving water whenever it is in operation!

The eco-ATWB-H is the ideal solution for: Maximized Water Savings, Highest Dry Bulb Switchovers, Plume Reduction or Plume Abatement.

Dry Mode (Sensible Heat Transfer)

In the dry mode, the process fluid enters the ARID fin Pak™ coil through the top coil connections. The fan motor is energized, while the spray pump is deenergized. The axial fan draws air upward through the louvers and across the coils. As the air passes over the ARID fin Pak™ coil, a portion of the load is dissipated to the atmosphere through the tube walls and fins using sensible heat transfer. The warm process fluid exits the ARID fin Pak™ coil, then enters the Ellipti-fin® coil through the factory installed piping. The remaining load is dissipated through the tube and extended surface fins of the Ellipti-fin® coil utilizing sensible heat transfer. The unit will remain in the dry mode of operation until the temperature set point can no longer be met. In this mode, NO water is used and plume is eliminated.


Evaporative mode (Latent and Sensible Heat Transfer)

Once the temperature set point can no longer be met, the unit will switch to the Evaporative mode. This mode of operation in the eco-Hybrid utilizes evaporative and dry cooling simultaneously. First, the process fluid enters the ARID fin Pak™ coil through the top coil connections. The fan and pump motors are energized. A portion of the heat load is transferred through the tube walls and fins to the air passing over the ARID fin Pak™ coil. No water is evaporated during this process. The warm process fluid exits the ARID fin Pak™ coil, then enters the Elliptifin® coil through the factory installed piping. The spray system cascades water over the tubes of the Ellipti-fin® coil while heat is absorbed by the water. Air is drawn

upward and over the coils by the axial fan. A small amount of the recirculating water is evaporated due to latent heat transfer through the tube and fin walls of the Ellipti-fin® coil. In this mode, water usage is reduced and plume is abated as the saturated discharge air is heated as it passes over the ARID fin Pak™ coil.

Ellipti-fin® Cooling Coil

The new eco-ATWB-H Closed Circuit Cooler utilizes Evapco's patented Ellipti-fin® coil design which assures even greater operating efficiency. The elliptical tube design allows for closer tube spacing, resulting in greater surface area per unit plan area than round-tube coil designs. In addition, the revolutionary Ellipti-fin® design utilizes elliptical spiral fin coil technology which has an inherent air side pressure drop lower than finned round tube designs. This permits greater water loading, making the new Ellipti-fin® coil the most effective design available.

The coils are manufactured from high quality steel tubing following the most stringent quality control procedures. Each circuit is inspected to ensure the material quality and then tested before being assembled into a coil. Finally, the assembled coil is pneumatically tested at 400 psig under water to ensure it is leak free.

To protect the coil against corrosion, it is placed in a heavy steel frame and then the entire assembly is dipped in molten zinc (hot-dip galvanized) at a temperature of approximately 800°F.

Maintenance Free ZMII® Spray Nozzle

Water Distribution System

EVAPCO’S Zero Maintenance ZMII® Spray Nozzle remains clog-free while providing even and constant water distribution for reliable, scale-free evaporative cooling under all operating conditions. The heavy duty nylon ZMII® Spray nozzles have a 1-5/16" diameter opening and a 1-1/2" splash plate clearance. Furthermore, the fixed position ZMII® nozzles are mounted in corrosion-free PVC water distribution pipes that have threaded end caps. Together, these elements combine to provide unequaled coil coverage and scale prevention, making it the industry’s best performing non-corrosive, maintenance-free water distribution system.

Superior Air Inlet Louver and Screen Design

The air inlet louver screens on the eco-ATWB are constructed of corrosion-free PVC. They are a two pass design that minimizes splashout and reduces the potential for algae formation inside the cooler.

In single pass louver systems used by other manufacturers, circulating water droplets tend to splashout, especially when the fans are shut off. With the two pass louver system, the water droplets are captured on the inward sloping pass, minimizing splashout problems.

This unique louver design completely encloses the basin area. Direct sunlight is blocked from the water inside the cooler, thereby reducing the potential of algae formation. Water treatment and maintenance costs are substantially reduced.

While effectively containing the recirculating water and blocking sunlight, the louver design has a low pressure drop. The low pressure drop results in lower fan energy consumption, which reduces the operating costs of the cooler.

Efficient Drift Eliminators

The eco-ATWB-H is equipped with an efficient drift eliminator system that effectively reduces entrained water droplets from the air discharge to less than 0.001% of the spray water flow rate.

The eliminators are constructed of non-corrosive PVC with a multi-pass design for maximum drift reduction. They are assembled in modular sections for easy removal and access to the water distribution system.

In addition to reducing drift, the eliminators also function as effective debris screens which protect the spray system from sunlight and debris.

ARID fin Pak™ Dry Cooling Coil

The new eco-ATWB-H Closed Circuit Cooler utilizes the ARID fin Pak™ Dry Cooling Coil. Installed in the air discharge of the cooler the ARID fin Pak™ dry cooling coil is piped in series with the evaporative cooling coil. The ARID fin Pak™ dry cooling coil is constructed of 304L Stainless Steel tubes and tubular Stainless Steel header with carbon steel coil connections for easy field piping. The fins have fully drawn collars to maintain consistent fin spacing and continuous surface contact over the entire tube to maximize heat transfer. The fins are constructed of Aluminum/Manganese alloy for superior corrosion resistance.

Fast, On-Time Shipments

The eco-ATWB is completely factory assembled and manufactured by a dedicated professional workforce, expert in building closed circuit coolers. Factory trained mechanics and EVAPCO's strict quality control and inspection procedures guarantee the quality of every unit shipped.

EVAPCO's controlled factory environment ensures fast on-time shipments, allowing the eco-ATWB to be available WHEN THE CUSTOMER WANTS IT!

IBC Compliant

 What is IBC?  

  • The International Building Code requires that evaporative cooling equipment must meet the same seismic or wind load forces as the building to which they are attached.

How does it apply? 

  • Based on project zip code and site design factors, calculations are made to determine the equivalent seismic "g force" and wind load on the unit.

What does EVAPCO offer?

  • Standard Structural Design

                    -Projects with ≤ 1.0g seismic or 145 psf wind loads

  • Upgraded Structural Design

                    -Projects with > 1.0g seismic or 145 psf wind loads

  • The upgraded structural design package for the New ATWB is designed for 5.12g and 145psf, making it applicable to ALL building locations in North America.

Water and Energy Conservation Control System

The best way to properly control and operate the eco-ATWB-H Closed Circuit Cooler is with the optional Sage2 ® Water and Energy Conservation Control System. The Sage2 ® is designed to optimally control the fan motor(s) and the pump motor(s) of the unit. The Sage2 ® will efficiently reject the building load using the minimal amount of water and energy.

Designed for easy maintenance, the eco-ATWB-H Closed Circuit Cooler leads the industry in service friendly features. The three most critical areas for closed circuit cooler maintenance are the basin, drive system, and coil. The eco-ATWB-H basin section is designed to allow quick and easy access from outside the cooler. Just like the basin, all service to the drive system can be safely performed from the side of the cooler, and EVAPCO's Power-Band drive system is the easiest belt drive system to maintain in the industry! The exclusive Ellipti–fin™ Technology (Patent Pending) and EVAPCO’s new ARID fin Pak™ dry coil are designed for trouble-free maintenance and long life straight from the factory.

Motor Mount, Power Band Belt Adjustment and Bearing Lubrication

The fan motor and drive assembly are designed to allow easy servicing of the motor and adjustment of the belt tension from the exterior of the unit. The T.E.F.C fan motor is mounted on the outside on these models and is protected from the weather by a cover which swings away for maintenance.

A large hinged access door is located on the side of the unit for easy access to the fan drive system. The belt can be adjusted by tightening the J-Bolts on the motor base and the tension can be checked easily through the access door, all while standing at the side of the unit. 

The bearings can also be lubricated from the side of the unit. The bearing lubrication lines have been extended to the exterior casing and are located by the access door, thus making bearing lubrication easy.

Sloped access ladders and working platforms are available as an option to facilitate maintenance.

Go to Optional Equipment for details.

Motor Mount, Power Band Belt Adjustment and Bearing Lubrication 

The T.E.A.O. fan motor is located inside the fan casing on the large eco-ATWB Closed Circuit Cooler, and is mounted on a rugged heavy duty motor base. The motor base is designed to swing completely to the outside of the unit through a very large, hinged (14 square feet) (1,3 square meters) access door greatly simplifying motor maintenance.

The unique swinging motor mount designed for these models features easy belt adjustment from the exterior of the unit. The T.E.A.O. fan motor is mounted on an adjustable base which is supported by two heavy duty galvanized steel pipes. The belt is adjusted by tightening an all-thread which runs through the motor base.

The innovative motor base features a unique locking mechanism for a positive belt adjustment and is also used to adjust the belt tension if a wrench is not available.

Bearing lubrication fittings are extended to the side of the unit inside the access door to allow easy application of the bearing lubricant. This external location allows for easy servicing of the bearings and is another important advantage of EVAPCO equipment.

To facilitate motor removal, an optional motor davit is available.

Go to Optional Equipment for details.

Easy, Removable Air Inlet Louvers with Quick Release Fasteners

The eco-ATWB-H features a Quick Release Fastener design consisting of (2) two large thumbscrews and a latch system. By loosening the thumbscrews, the latch pulls up and out of the louver frame, allowing the louver to be removed while the latch and thumbscrews stay on the closed circuit cooler.

 Easy Access

The cold water basin section is easily accessible from ground level by simply removing the (2) two Quick Release Fasteners on the inlet louver assemblies surrounding the closed circuit cooler and lifting out the lightweight louver.

The basin can be accessed from all (4) four sides of the cooler. This open basin design enables the eco-ATWB basin to be easily cleaned.

Clean Pan Design

The eco-ATWB-H features a sloped basin from the upper to lower pan section. This "Clean Pan" design allows the water to be completely drained from the basin. The closed circuit cooler water will drain from the upper section to the depressed lower pan section where the dirt and debris can be easily flushed out through the drain. This design helps prevent buildup of sedimentary deposits, biological films and minimizes standing water.

Stainless Steel Strainers

The EVAPCO standard for many years, the stainless steel strainer is one component of the closed circuit cooler subject to excessive wear and corrosion. With stainless steel construction, this component will last the life of the cooler.

Drive System

The eco-ATWB-H Evaporative Cooler features the highly successful EVAPCO POWER-BAND Belt Drive System engineered for heavy-duty operation. The POWER-BAND Drive System has consistently provided trouble-free operation in the most severe duty evaporative condenser applications. In addition, the complete drive system including the fan motor is standard with a (5) Five Year Warranty.

Fan Motors

All eco-ATWB-H Closed Circuit Cooler models utilize heavy duty totally enclosed (T.E.F.C. or T.E.A.O) fan motors designed specifically for closed circuit cooler applications. In addition to the standard motors offered on each cooler, EVAPCO offers many optional motors to meet your specific needs, including:

  • Premium Efficiency Motors 
  • Multi-Speed Motors
  • Inverter-Duty Motors for VFD Applications

8.5' (2,6 m) wide eco-ATWB-H models feature T.E.F.C. motors are located on the outside of the unit, protected by a hinged, swing away cover. 12' (3,7 m) wide eco-ATWB-H models have T.E.A.O. motors located inside the fan section on a heavy duty motor base which swings to the outside for repair or removal.


Five (5) Year Warranty

EVAPCO provides a standard five (5) year motor and drive warranty on all direct drive Power-Band belt drive and optional gear drive eco-ATWB-H Closed Circuit Coolers. This unique warranty is designed to offer the end user optimum protection against fan drive and motor failure. It is a comprehensive plan which includes the fan, fan shaft, belts, sheaves, fan bearings, gear box, flexible coupling, driveshaft and the motor.

Fan Shaft Bearings

The fan shaft bearings on the eco-ATWB-H Closed Circuit Cooler are specially selected to provide long life, minimizing costly downtime. They are rated for an L-10 life of 75,000 to 135,000 hours, making them the heaviest duty pillow block bearing in the industry used for Closed Circuit Cooler duty.

Drive System Sheaves

Drive system sheaves located in the warm, moist atmosphere inside the closed circuit cooler are constructed of an aluminum alloy. Those located externally are protected by a hinged cover.

Power-Band Belt Drive

The Power-Band drive is a solid-back multigroove belt system that has high lateral rigidity. The belt is designed for closed circuit cooler service, and is constructed of neoprene with polyester cords. The drive belt is sized for 150 percent of the motor nameplate horsepower ensuring long and trouble free operation.

Optional Equipment

The standard design of the EVAPCO eco-ATWB-H provides the customer with the most efficient and easiest Closed Circuit Cooler to maintain in the industry. There are additional options which can make maintenance easier, extend the life, or enhance the performance capabilities of the Closed Circuit Cooler. These options are listed below.

Sloped Access Ladders

A sloped access ladder is available for 8.5' and 12', (2,6 and 3,7m) wide eco-ATWB-H models. The EVAPCO designed access ladder features a sloped "ships type" ladder arrangement which provides fast and easy access to the water distribution system and drive components. A grab bar is attached to the sloped ladder for safe and easy ascent and descent. There is no need for safety cages or railings with this design. The ladder(s) will ship loose and must be field mounted. The sloped ladder meets all applicable OSHA requirements.

Stainless Steel Water Basin

EVAPCO coolers have a modular design which allows specific
areas to be enhanced for increased corrosion protection. The
basin area of the cooler experiences turbulent mixing of air
and water, in addition to silt build-up. In conjunction with the
EVAPCOAT Corrosion Protection System, EVAPCO offers an optional Stainless Steel Basin. This option provides Type 304 or 316 stainless steel for the entire basin area including the support columns of the cooler and the louver frames. The basin section provides structural support for the unit; it is also the part of the unit that is most prone to corrosion. For maximum protection against corrosion, EVAPCO can provide a Stainless Steel Basin as an affordable option.

Working Platform & Ladder with Davit

Eco-Coolers are available with a self-supported external working platform and ladder. Two separate platforms will allow easy access to the motor and drive system, water distribution system as well as the ARID-fin Pak™ coil. The working platforms are constructed of the heavy duty galvanized steel. The OSHA compliant working platform option uses a straight ladder as standard and ships in sections for easy installation.

The optional davit eliminates crane rentals and facilitates the removal of motors and fans. The davit is constructed of aluminum for ease of use. When the davit is ordered, the galvanized steel bracket is mounted on the side of the unit. The Davit ships loose and is installed in the field.

Electric Water Level Control

EVAPCO closed circuit coolers are available with an optional electric water level control system in place of the standard mechanical makeup valve and float assembly. This package provides very accurate control for the basin water level and does not require field adjustment, even under varying operating conditions.

The control was designed by EVAPCO and is manufactured exclusively for EVAPCO. It consists of multiple heavy duty stainless steel electrodes. These electrodes are mounted external to the unit in a vertical stand pipe. For winter operation, the stand pipe must be wrapped with electric heating cable and insulated to protect it from freezing.

The weather protected slow closing solenoid valve(s) for the makeup water connection is factory supplied and is ready for piping to a water supply with a pressure between 5 and 125 psig (35 kPa and 860 kPa).

Electric Immersion Heaters

Electric immersion heaters are available as an option and are located in the basin of the cooler. They are sized to maintain a +40°F (4.4°C) pan water temperature at 0°F (-18°C) ambient with the fans off *. They are furnished with a thermostat and low water protection device to cycle the heater on when required and to prevent the heater elements from energizing unless they are completely submerged. All components are enclosed in rugged, weather proof enclosures for outdoor use. Heater control packages that include contactor, transformer or disconnects are available.

(*) - Electric heater selection based on 0°F (-18° C) ambient temperature. For alternate low ambient heater selections consult the factory

Remote Sump Configuration

For units operating in areas where temperatures may be very low, or where low temperatures may occur during periods when the unit is not operating, a sump located inside the building is the preferred means of ensuring that the basin water will not freeze. For these applications, the cooler will be supplied without the spray pump, suction strainers and all associated piping, but is furnished with an oversized bottom outlet.

Solutions for Sound Sensitive Applications

The eco-ATWB-H Closed Circuit Coolers are now available with four (4) equipment options to reduce the overall sound generated from the side or top of the eco Closed Circuit Cooler. Each option provides various levels of sound reduction and options can be combined to provide the lowest sound level. Consult EVAPCO’s evapSelect selection program for unit sound levels. If a detailed analysis or full octave band data sheet is required for your application, please consult your EVAPCO Sales Representative.

NOTE: These low sound options may impact the overall installed dimensions of the eco-ATWB-H Closed Circuit
Cooler selected.

Pulse~Pure® Water Treatment System

The eco-ATWB-H is available with EVAPCO’s optional Pulse~Pure® non-chemical water treatment system. The Pulse~Pure® Water Treatment System utilizes pulsed-power technology to provide CHEMICAL FREE Water Treatment and is an environmentally responsible alternative for treating water in evaporative cooled equipment. It does not release harmful by-products to the environment and eliminates costly chemicals completely from cooler drift and blowdown. The Pulse~Pure® system delivers short, high-frequency bursts of low energy electromagnetic fields to the recirculating water in the eco-ATWB-H and will:

  • Control Bacteria to Levels Well Below Most Chemical Water Treatment Programs
  • Control the Formation of Mineral Scale on Heat-Exchange Surfaces.
  • Save Water by Operating at Higher Cycles of Concentration
  • Yield Corrosion Rates Equivalent to Chemical Water Treatment

More benefits of offering EVAPCO’s Pulse~Pure® Water Treatment System on the new eco-ATWB are:

  • Pulse~Pure® Factory Mounting - Factory Installation of the Pulse~Pure® System Guarantees Your Water Treatment is Installed to Factory Specifications.
  • Integral Cutting Edge Conductivity Control and Blowdown Packages that are contained in a single feeder panel:


Conductivity Control Package – Measures Conductivity Utilizing a Non-Fouling Torodial Probe
and Features:

  • One power connection of 120 volt or 460 volt is all that is required.
  • USB port for downloadable 60 day audit trail of system operation.
  • Self draining conductivity loop.

Motorized Blowdown Valve – Standard for the most reliable operation in bleed control. Three-way valve operation provides good bleed flow without a standing column of water.


Because ongoing water treatment service is an absolute requirement for any evaporative cooled system, each purchase of a Pulse~Pure® Water Treatment System includes, as standard, a 1 year water treatment service and monitoring contract provided by your EVAPCO Representative EVAPCO’s Pulse~Pure® system offers eco-ATWB-H owners a single-source of responsibility for equipment, water treatment and service. Patent #: 7,704,364

SECTION 23 65 00






A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section.


A. This Section includes factory assembled and tested, closed circuit mechanical induced-draft vertical discharge closed circuit cooler.


A. Product Data: For each type of product indicated. Include rated capacities, pressure drop, performance curves with selected points indicated, furnished specialties, and accessories.

B. Shop Drawings: Complete set of manufacturer's prints of evaporative equipment assemblies, control panels, sections and elevations, and unit isolation. Include the following:

1. Assembled unit dimensions.

2. Weight and load distribution.

3. Required clearances for maintenance and operation.

4. Sizes and locations of piping and wiring connections.

5. Wiring Diagrams: For power, signal, and control wiring. Differentiate between manufacturer installed and field installed wiring.

C. Operation and Maintenance Data: Each unit to include, operation, and maintenance manual.


A. Verification of Performance:

1. Manufacturer shall have a thermal performance testing program for water cooling towers certified by the Cooling Technology Institute (CTI) in accordance with CTI Specification Standard STD-201. Manufacturer’s performance guarantees or performance bonds shall also be accepted.

2. Unit Sound Performance ratings shall be tested and certified according to CTI ATC-128 standard. Sound ratings shall not exceed specified ratings.

B. Unit shall meet or exceed energy efficiency per ASHRAE 90.1


A. Submit a written warranty executed by the manufacturer, agreeing to repair or replace components of the unit that fail in materials and workmanship within the specified warranty period.

1. Fan Motor/Drive System: Warranty Period shall be Five (5) years from date of unit shipment from Factory (fan motor(s), fan(s), bearings, mechanical support, sheaves, bushings and belt(s))

2. The Entire Unit shall have a comprehensive one (1) year warranty against defects in materials and workmanship from startup, not to exceed eighteen (18) months from shipment of the unit.

3. Heat Transfer Coil: Warranty Period shall be one (1) year from date of unit shipment from Factory.



A. Manufacturers: Subject to compliance with requirements, provide closed circuit coolers manufactured by one of the following:

1. EVAPCO Model eco-ATWB-H ______________

2. Approved Substitute


A. Each unit shall be capable to cool ___GPM of water entering at ___ºF leaving at ___ºF at a design wet bulb of ___ºF with a pressure drop across the coil not to exceed ___ psi.


A. Description: Factory assembled and tested, induced draft counter flow closed circuit cooler complete with fan, coil, louvers, accessories and rigging supports

B. Materials of Construction

1. All cold water basin components including vertical supports, air inlet louver frames and panels up to rigging seam shall be constructed of heavy gauge mill hot-dip galvanized steel.

2. Upper Casing, channels and angle supports shall be constructed of heavy gauge mill hot-dip galvanized steel. Fan cowl and guard shall be constructed of galvanized steel. All galvanized steel shall be coated with a minimum of 2.35 ounces of zinc per square foot area (G-235 designation). During fabrication, all galvanized steel panel edges shall be coated with a 95% pure zinc-rich compound.

C. Fan(s):

1. Shall be high efficiency axial propeller type with aluminum wide chord blade construction. Each fan shall be statically balanced and installed in a closely fitted cowl with venturi air inlet for maximum fan efficiency.

D. Drift Eliminators

1. The eliminators shall be constructed entirely of Polyvinyl Chloride (PVC) in easily handled sections. Design shall incorporate three changes in air direction and limit the water carryover to a maximum of 0.001% of the recirculating water rate.

E. Water Distribution System

1. Spray nozzles shall be zero-maintenance heavy duty molded nylon with large 1-5/16" orifice diameter opening and internal sludge ring to eliminate clogging. Spray header, branches, and riser shall be Schedule 40 Polyvinyl Chloride (PVC) for corrosion resistance. Branches shall have threaded end caps to facilitate debris removal.

F. Heat Transfer Media

1. Heat transfer coil shall be elliptical tubes of prime surface steel, encased in steel framework with entire assembly hot-dip galvanized after fabrication. All coil rows shall feature extended surface fins designed with sloping tubes for liquid drainage and tested to 400psig air under water. Coil shall meet strength requirements of ASME/ANSI B31.5.

2. Unit shall be constructed of 5/8” diameter type 304L stainless steel round tubing with carbon steel connections. Marine grade aluminum fins with a fin density of 10 fins per inch and fully drawn collars shall be used. Tubing shall be hydraulically expanded into the fin plate for consistent contact. Dry coil shall be piped in series with heat transfer coil and designed for full unit flow.

G. Pump

1. Unit shall have an EISA compliant, close-coupled centrifugal pump with mechanical seal. The pump shall be installed in a vertical position so that water will drain from the pump when the cold water basin is emptied. Pump motor shall be totally enclosed with protective canopy for outdoor operation.

H. Bleed-off

1. Unit shall have a waste water bleed line with adjustable valve provided.

I. Air Inlet Louvers

1. The air inlet louvers shall be constructed from UV inhibited polyvinyl chloride (PVC) and incorporate a framed interlocking design that allows for easy removal of louvers for access to the entire basin area for maintenance. The louvers shall have a minimum of two changes in air direction and shall be of a non-planar design to prevent splash-out, block direct sunlight and debris from entering the basin.

J. Electronic Water Level Control

1. Electronic water level control package shall have five (5) stainless steel water level sensors (one (1) high level, one (1) high level alarm, one (1) low level, one (1) low level alarm and one (1) ground) with a NEMA 4X enclosure mounted in a cleanable Schedule 40 PVC external standpipe with slow closing solenoid valve(s) and "y" strainer(s). Wiring is not included and components must be field mounted. Valves shall be sized for 25 psig (172 kPa) minimum to 125 psig (862 kPa) maximum pressure. Standpipe may require heat tracing by others in cold weather applications.

K. Pan Strainer

1. Pan Strainer shall be all type 304 stainless steel construction with large area removable perforated screens.


A. General requirements for motors are specified in Division 23 Section “Motors”

B. Fan Motor

1. Fan motor(s) shall be totally enclosed, ball bearing type electric motor(s) suitable for moist air service. Motor(s) are Premium Efficient, Class F insulated, 1.15 service factor design. Inverter rated per NEMA MG1 Part and suitable for variable torque applications and constant torque speed range with properly sized and adjusted variable frequency drives.

2. Fan motor(s) shall include strip-type space heaters with separate leads brought to the standard motor conduit box.

C. Fan Drive

1. The fan drive shall be multigroove, solid back V-belt type with taper lock bushings designed for 150% of the motor nameplate horsepower. The belt material shall be neoprene reinforced with polyester cord and specifically designed for evaporative equipment service. Fan and motor sheave shall be aluminum alloy construction. Belt adjustment shall be accomplished from the exterior of the unit.

D. Fan Shaft

1. Shaft shall be Solid, ground and polished steel. Exposed surface coated with rust preventative.

E. Fan Shaft Bearings

1. Fan Shaft Bearings shall be heavy-duty, self-aligning ball type bearings with extended lubrication lines to grease fittings located on access door frame. Bearings shall be designed for a minimum L-10 life of 75,000 hours.


A. Fan Section

1. Access door shall be hinged and located in the upper casing for fan drive and water distribution system access.

B. Basin Section

1. Framed removable louver panels shall be on all four sides of the unit for pan and sump access.

C. Internal Working Platform

1. Internal working platform shall provide for easy access to the fans, belts, motor, sheaves, bearings, all mechanical equipment and complete water distribution system. The coil surface shall be an acceptable means of accessing these components.


A. Basin Heater Package

1. Cold water basin shall be fitted with copper-element, electric immersion heater(s) with a separate thermostat and low water protection device. Heaters selected to maintain +40 F pan water at 0 F ambient temperature.

2. Electric immersion heater package shall include a factory-supplied NEMA 4x enclosure containing a magnetic contactor with 120V control circuit, transformer, and main power disconnect. Control package wired by others.


Thermal Performance

Flow tables1.99 MB
Flow tables 30%PG1.97 MB
Flow tables 30%EG2.23 MB