— Cooling Tower Options, Accessories, and Parts

Air Flow Switch

The airflow switch is a desirable cooling tower component when loss of airflow will have an adverse effect on system operation.  This switch will indicate loss of airflow from many causes including, but not limited to, belt slippage, belt failure, motor failure, thermal overload shutdown, media failure, etc.  The airflow switch is an on/off device that can be operated in two modes:

  1. Will indicate a total loss of airflow as installed at the factory, or
  2. Can indicate loss of a limited amount of airflow by varying the insertion depth of the sensing elements.

The enclosure is rated NEMA 7 and 9 as standard. The contacts have a rating of 5 amperes at 125/250 VAC and are SPDT.  It can be utilized for system shutdown, warning lights, or other functions.

High temp drift/mist eliminator

This cooling tower part is used when the inlet water temperature entering the cooling tower will be greater than 160°F. High Temp Drift Eliminator would replace the standard PVC material inside the cooling tower with polypropylene fill material.  The High Temp Drift Eliminator is a cooling tower component that can withstand water temperatures up to a maximum 180°F and spikes of 195°F.


cooling tower partsThis cooling tower component is an anti-microbial resin that is fully compounded into the base cooling tower material. The anti-microbial resin contains additives that operate on a cellular level to continuously disrupt and prevent the uncontrolled growth of microorganisms and biofilm within the cooling tower. Efficacy tests were performed by Special Pathogens Laboratory, The Legionella Experts®

Antifreeze package / Resistance heating option

The antifreeze package is supplied to provide protection against freezing of standing water in the cooling tower sump due to shutdown during winter operation.  The option is provided when draining the system during periods of a prolonged shutdown is not feasible, such as during weekends, or when a separate gravity feed indoor storage tank is not part of the re-circulation system.  Resistance heating of the sump water provides protection, and this package includes the following cooling tower parts and components:

NEMA 4X Enclosure with fused disconnect, solid state printed circuit board pre-set to 45°F on/off temperature control with 5°F switching differential and built-in low level cut off, electric immersion heater, sensor probe with cord to measure both water temperature and water level and heater wiring diagram.

Immersion Heaters are sized as follows:

t10 thru t25  2000 watt
t30 & t40 4500 watt
t50 thru t150 6000 watt
T55i thru T175i 6000 watt
T200i thru T250i 9000 watt
TR-2xx812 6000 watt
TR-3xx812 9000 watt
TM Series 6000 watt per cell


Antifreeze package / Solenoid drain valve

This option is utilized when freezing of standing water in the cooling tower sump could occur due to system shutdown during winter operation.  An electrically actuated valve will open when the pumps are not operating and the temperatures approach freezing.  The valve can be installed in the sump drain fitting of the tower (at the factory) or remotely at the piping low point (by others in the field).

Components provided are:

  1. Electrically actuated to close, spring to open, 2-way valve, 1” line size, with NEMA 4 enclosure.
  2. 1” PVC tee
  3. 1” PVC plug
  4. Temperature switch with bulkhead fitting

When power is removed the valve automatically reverts to the open position.  This feature ensures freeze protection even during a power outage.

Blower coating, Premium (Pioneer models only)

Premium blower protection is desirable when the unit will be operated in highly corrosive atmospheres such as paper mills, coastal areas, chemical plants, etc. This premium blower corrosion protection option consists of complete acrylic vinyl polymer encapsulation of the blower wheel and housing and frame. A T-304 stainless steel blower shaft is also included.

This option offers an extremely cost effective alternative to FRP blower assemblies. The blowers and frames are prepared at the factory with all holes and cutouts completed. The entire assembly is sandblasted, then coated with the highly durable acrylic vinyl polymer to 10mil thickness.   The blower wheel is coated in the same manner, except for the shaft bore, and is then re-balanced both statically and dynamically.

After final assembly, the shaft and sheaves are coated with a specially formulated shaft coating material which conforms to MIL-C-16173D, GR 1 & 4.

The result is a blower assembly which will give years of corrosion free service even under the most adverse conditions.

Blower protection hood (Pioneer models only - Standard with ALL Pioneer towers)

BLOWER HOOD: The blower hood completely encloses the blower to offer maximum protection from outdoor elements, as well as to personnel who might accidently contact the rotating components.   The hood is molded from the same polyethylene material as the cooling tower shell, and therefore it’s appearance is consistent with the tower.  The blower hood also serves as an additional sound dampening device.  With these hoods properly installed, a 3 dBA reduction at 5 feet is common.  The hood inlets are covered with a PVC coated 3/8″ #2 wire mesh screen fastened to the hood with stainless steel hardware.  NOTE:  This option comes standard with all Pioneer towers.

Bottom outlet

The Bottom Outlet is a convenient option when gravity-draining a part of the cooling tower.  This minimized the amount of standing water in the sump of the cooling tower. A 125lb. Flanged fitting is provided.  Provisions must be made in the mounting platform for the fitting.  The platform, indoor storage tanks, and other fittings can be provided by Delta.

Control panel

A control panel is required any time there are electrical devices involved in a system.  The standard features and parts of a Delta Cooling Tower's supplied control panel are:

  1. NEMA 3R water-tight enclosure
  2. Single-speed motor starter
  3. 110V transformer with fuses
  4. Fan Motor operating lights
  5. Fan Motor selector switches
  6. Terminal strips
  7. 208V or 230V or 460V or 575V / 3Ph / 60Hz

Optional items available:

  • Disconnect switch: either fused, unfused or magnetic circuit breaker type.
  • Additional motor starters, selector switches, and lights to interface with existing systems, remote pumps, etc.
  • Any other NEMA enclosure manufactured.
  • Pre-mounting of control panel and pre-wiring of skid-mounted options with Liquid-Tite conduit or EMT. (Consult factory for additional pricing)

Delta also can provide programmable controllers, computer interfacing, telemetry, and any other type of control system required.  Pre-mounting and pre-wiring of the control panel for a system installation are available.  This minimizes the labor required for field installation.

CPVC Water distribution system piping

This option is used when the inlet water temperature entering the cooling tower will exceed 140°F.  CPVC piping would replace the standard PVC piping, and can be used with water temperatures up to 150°F with standard PVC fill and up to 180°F with High Temp fill.

Delta SSC dual biocide water treatment package

Pre-assembled water treatment equipment package.  Monitor and control your tower’s water with a user friendly controller featuring: conductivity, temperature, flow switch, 16 line display, onboard history, 10 service notepads, five control relays, two water meter inputs, 5 digital inputs, optional 4-20mA inputs/outputs and optional internet, Bacnet or Modbus communications. 

The controller, three 30 gpd @ 100 psi dual adjustment chemical metering pumps and a 3/4″ motorized bleed valve are pre-mounted and wired on a heavy duty 1/2″ blue poly panel along with a complete 3/4″ PVC sample stream assembly that include true union isolation valves, strainer, sample valve, flow switch, back check, and three quick release injection tees.

Electronic Water Makeup System (with High & Low Alarms)

This option replaces the standard mechanical float valve makeup assembly to electronically maintain the water level in the cooling tower sump.  The package uses multiple corrosion-resistant probes housed in an externally mounted standpipe to control the electronic solenoid make-up valve (included) and provide an additional High & Low-level alarm. All controls are housed in a Nema4X enclosure with 50' prewired cable.

Electronic Water Makeup System (without Alarms)

This option replaces the standard mechanical float valve make up assembly to electronically maintain the water level in the cooling tower sump.  The package uses multiple corrosion resistant probes housed in an externally mounted standpipe to control the electronic solenoid make-up valve (included).  All controls are housed in a Nema4X enclosure with 50' prewired cable.

Equalizer fittings (Standard on TM Series models)

This option is desirable for multiple module installations to provide equal liquid levels in the sumps of the individual modules and allows for the installation of only one (1) water make-up line.  Delta provides the bulkhead fittings installed in the cooling towers to provide for gravity flow from one tower sump to another.  The equalizer connection is not for full flow transfer (ex: pumping from one unit to another).

The connecting piping should be field installed and is the responsibility of others.

Fan assembly coating

The standard fan coating provided for the cooling tower fan ring and guards is a polyamide epoxy with high solids content to ensure protection of sharp edges, corners and welds.  This coating provides excellent chemical resistance to a wide range of acids, alkalies, solvent and water solutions.  When dry, the coating can withstand up to 400°F temperature.  The fan ring and guard steel surfaces are sand blasted and a primer is applied prior to the final application.

Also available in 304SS or 316SS for an added charge.

Flanged adaptors (Standard on TM Series models)

This option provides 150lb Schedule 80 PVC flanged connection at approximately 6” – 8” projection from the cooling tower.  Gaskets and hardware are not provided by Delta and should be provided by others with the piping companion flange.

Fused disconnect switch

All motors on the cooling tower are wired back to a single NEMA 3R Fused Disconnect Switch with individual terminals for each motor wire.  A flexible conduit is run between the disconnect switch and each component.

High sump level switch

The high sump level switch option is utilized when a potential overflow must be avoided.

Switch elevation is set below the point when the water in the sump will overflow onto the ground.

The switch can be used to illuminate a light, shut off the influent feed pump or initiate some other device or alarm.  This package consists of a NEMA 7 and 9 liquid level switch mounted in a PVC bulkhead fitting assembly with a 2” x 1” reducer bushing.

High temp fill/wet decking

cooling tower parts This cooling tower part and option is used when the inlet water temperature entering the cooling tower will be greater than 150°F. High Temp Fill would replace the standard PVC fill material inside the cooling tower with polypropylene fill material.  The High Temp Fill can withstand water temperatures up to a maximum 180°F and spikes of 195°F.

Ladder (not offered on Pioneer models)

The ladder assembly facilitates access to the upper section of the cooling tower for inspection and maintenance of the water distribution system and fan assembly as required.  The assembly is fabricated of aluminum for lightweight installation and has skid resistant rungs and landing platform.  The landing platform is specifically placed to maximize accessibility to the man-way located in the conical section of the tower for easy access and servicing of components.  The ladder conforms to all OSHA requirements.  In some cases the cage assembly may be required.  The unit is attached to the tower via (4) bolted connections and two base mounting bolts.


Louver Filters (NOT offered on Pioneer models)

PVC coated polyester mesh screening that attaches over existing PVC louvers to prevent smaller size debris from entering the cooling tower.  Filters are weather/rot resistant and can easily be removed for cleaning.


Low sound fan package (NOT offered on Pioneer models)

LOW SOUND option utilizes a Wide Chord Blade Fan Prop with a direct drive 720rpm speed system to achieve large reductions in sound noise.  At ground levels, sound pressure levels are reduced 4-8 dB(A); Overhead, sound pressure levels are reduced 10-17dB(A). (Depending on model tower and site dynamics).  Designed to have the same very high efficiency as standard designs, utilizing premium efficient motors, resulting in the no de-rate in cooling tower capacity.

NOT offered on Pioneer models

Motor Davit

The motor davit assembly allows customers to change out cooling tower motors on TM Series Cooling Towers safely without renting a crane. Renting a crane is a costly expenditure that can be avoided with this simple apparatus. The design of the motor davit is to fit on the side of a TM-Series tower and attach to the lifting lugs molded into the tower shell. The davit is light enough to be carried up by one person and is simply attached using one bar through the lifting lugs and outer support of the davit. Once the davit is secured to the tower, it can be used to lift the motor up and down to the top of the tower shell.

The electric winch requires only 120V power to operate. Attach the davit to the motor lifting lugs (do not lift off any other section of the motor) and use the controls to raise and lower the motor. The davit can easily be turned by hand to rotate the motor into position. Once the motor is lifted up to the top of the tower and rotated into position, it can then be mounted to the motor base plate in the same position as the one removed. The propeller and bushing will then need to be attached to the new motor shaft.

Motor space heater

Fan Motor Space Heaters are recommended for installations where temperature variations can cause excessive condensation within the motor.  The Space Heater controls can be incorporated in our Control Panel and would be designed for automatic and manual operation.  While the motor is operating, the heater remains off.  When the motor shuts down, the heater is automatically energized during the off cycle.  The Control Panel would be designed with manual on/off control for intermittent cycles of operation.  Heaters are available for 115, 230, 460, or 550 volts, 3 phase, 60-cycle operation.

Outlet strainer basket

This option is desirable to prevent debris that may have entered the cooling tower sump from getting into the pump, or the rest of the cooling water system.  This option is recommended to minimize particle size that could foul chillers, heat exchangers, compressors or the cooling tower distribution laterals.

A vortex breaker pipe, which is provided as standard on pump suction applications, is included to maximize the inlet area and prevent cavitation.  The strainer is made from a vortex breaker pipe surrounded by 1/4″ #2 PVC coated mesh screen.  Finer mesh screens can be overlaid to minimize particle size.

Platform (not offered on TM Series models)

The platform is beneficial in installations where a flat and level surface is not available for mounting Delta’s cooling towers.  The steel platform is also utilized for replacement installations where only “I” beams, or other forms of support exist.  This steel platform is finished in a black air-dried phenolic paint.

The platform is shipped in two separate pieces, for transportation purposes, and must be supported in the field by others.  An optional walkway can be supplied to allow for accessing the cooling tower sump, should the platform be elevated.

Platform stand

The platform stand option is the supporting steel legs used to raise the platform option supports the cooling tower base.   The stands are available in 10’, 12’ and 14’ heights and can also be customized to meet the applications requirements.


The pump package is offered to allow for single source responsibility of cooling tower equipment.  The size of the pump is determined by two factors:

  1. Flow rate
  2. Total dynamic head

The customer is responsible for supplying this information.  The pumps come complete closed-coupled with mechanical seals and ODP, 208/230/460V, 3 phase motor.  TEFC motors are available.

Safety cage (not offered on Pioneer models)

Complementary to the ladder option.  Extends above the ladder-landing platform for extra protection while accessing the top of the cooling tower. The safety cage is assembled to the ladder at the factory for ease of installation.  This assembly is attached directly to the cooling tower shell during installation.

The safety cage may or may not be required depending on OSHA specifications.  The cage assembly is manufactured of the same type of aluminum as the ladder.

Side stream filtration system

This is a smart option to add to any cooling tower, size to 8-10% of full tower flow. These systems will continuously filter a portion of the cooling water to remove suspended solids and buildup particles, reducing the possibility of fouling and biological growth. This results in water savings and increased energy efficiency due to a decrease of scale formation.

Engineered, factory assembled and user friendly. The system utilizes a 100micron strainer to remove fine particulate from the process water and also includes an automated flush system. All skids and supports are 304 stainless steel, ensuring the system remains operational for many years.

Simplex & Duplex strainers

These Simplex & Duplex strainers are a cost effective way for removing damage causing particulate matter from process water, protecting system components such as flow meters, pumps, and spray nozzles.   The clamp type cover is easily removed without tools, making cleaning or change outs quick and easy.  Features include a cast iron housing, hand removable cover, removable perforated stainless steel basket, Buna seals and drain plug.

Single point connection/Junction box

All Motors on the cooling tower are wired back to a single NEMA 3R junction box with individual terminals for each motor wire.  Vibration Switches are also wired to the junction box if included on the order.  Flexible conduit is run between the junction box and each component.

Spray nozzle distribution system (Paragon model only)

This part of a cooling tower is an option available on the Paragon series to replace the standard rotating sprinkler head assembly with a fixed spray nozzle system and upgraded drift eliminator. The system is made up of a PVC lateral tree system with removable threaded spray nozzles sized for the specified flow rate and design conditions.

Stainless steel basket strainers

stainless cooling tower componentStainless steel strainers are used to remove solid particles from liquid streams.  These strainers feature a stainless steel housing and fine mesh conical shaped screen.  They handle flow rates from 10 GPM to 2,000 GPM and operating pressures up to 150 psi.  Higher flow rates may be achieved by manifolding multiple filters.

Unlike traditional basket strainers, y-strainers, or bag filters, these units can be flushed while online and in service.  Settled debris is easily removed by purging through the debris flush port.  They are also available with the following options:

  1. Pressure Differential Alarm Package – This alarm package continually monitors the inlet and outlet system pressure. When the filter screen becomes clogged, the pressure differential switch gauge will trigger an audible siren and visual flashing alarm. These alarms are intended to alert maintenance personnel that the strainer screen needs to be removed and cleaned.
  2. Automatic Timer Flush Package – This system will ensure that your strainer is always flushed. By using a dirty water diaphragm valve and a timer-based valve controller, debris purging is automated. The timer controller is easy to use, water-resistant, and can be powered with 9-volt batteries or AC power.

The strainers also operate with less than 1-PSI pressure loss at maximum flow, when clean.  This efficiency results in dependable filtration without constricting your system’s flow rate or causing unnecessary pressure loss to downstream equipment. 

Storage tank

The tank is utilized when extra water capacity is required.  Potential applications are for system modulation when pumping flow rates vary, or for water storage.  A hot/cold tank arrangement may be required in those cases where the process hot water exceeds the maximum allowable inlet water temperature.  The cooling tower would flow more water than the process and the difference would be mixed with the hot water to reduce its temperature.  The tank and optional cover are fabricated of medium density polyethylene.  All fittings are Type 1 PVC.

Thermostats – Single Stage and Two-Stage

The fan thermostat is important to minimize operating costs.  The thermostat senses water temperature and controls fan operation during cold weather service.  When cold-water temperature drops below design, the fan will shut off saving motor hp operating costs.

A single stage thermostat controls the fan on/off and is provided with a standard single speed motors.

A two-stage thermostat is recommended for two speed motor operation and controls the fan from ‘on’ to ‘half speed’ and then to ‘off’.  At half speed operation the motor operates at only ¼ full load BHP.  Two stage thermostats must be wired to Delta specifications.

As the cold-water temperature rises and approaches the design temperature, the thermostat signals the fan to start in order to maintain the cold water design temperature.  The thermostat has a 5°F differential in its operating range of 30°F to 130°F.  The contacts are SPDT and have a 15 Amp UL rating.  They are complete with NEMA 4 enclosures suitable for outdoor mounting.  The thermostat can be provided loose, or installed in the cooling tower sump, or an indoor storage tank.  When the thermostat is supplied with a cooling tower or storage tank provided by Delta, the package includes installation with a ¾” Schedule 80 PVC bulkhead fitting and a ¾” x ½” Schedule 80 PVC reducer bushing.  Thermostat operating range must be set in the field.  Recommended setting is approximately 70°F to 72°F, but will vary depending on the application and the installation location.

Two-speed fan motor

Two speed fan motors provide cold-water temperature control by means of airflow modulation, allowing for design cold-water temperature at minimum operating cost.  When provided with a two-stage thermostat, the motor can be reduced to half speed when cold water sump temperature approaches design.  The motor will shut off when the cold-water temperature falls below design.  Two-speed TEFC motors are provided for single voltage 3-phase operation only.  Single-phase dual voltage motors are not available.  NOTE: a ½ reduction in motor speed corresponds to ½ reduction airflow.  At half speed operation, only 1/8 BHP is consumed.

Upper handrail system (Premier & TM Series models only)

An optional upper safety handrail system is available to provide protection while on top of the cooling tower inspecting or working on the mechanical equipment. This option is shipped pre-fabricated for assembly in the field.

Variable frequency drive package

The Variable Frequency Drive Package is an energy savings device that allows speed control of the cooling towers fan motors.  The standard package includes a NEMA 1 or NEMA 3R enclosure with a VFD, electronic 3-contactor bypass, fused disconnect and 3% input line reactor.  The bypass configuration allow for isolation of the VFD for maintenance or adjustment while the cooling tower is still in operation.  The drives also include Modbus, communication protocol standard.  Other protocols are available.  Drive packages are also available with the following options:

  1. Digital Temperature Controller to automatically adjust the fan speed based upon the sump water temperature.
  2. Pump Motor Starters to control the operation of the cooling tower pump

Vibration cutout switch

cooling tower switch accessoryThe vibration cutout switch option is utilized to shut down the rotating mechanical fans in the event of excessive vibration.  This device helps prevent further potential damage by shutting the motor off.  It is wired in series with the motor starter coil and has dry contact rating of 10-ampere capacity at 120 VAC. Nema 4X/IP66.

Delta provides the vibration cutout switch installed on the blower when ordered as a component of a new cooling tower or on a replacement blower assembly.