Application Case Study: Temperature Monitoring in Land Management Vehicles

 Application Case Study:  Temperature Monitoring in Land Management Vehicles

Taking a wetland vehicle out into a marsh can be daunting.  Looking out at miles of open marsh, you get the same feeling as gazing deep into forested mountains or across towering ocean waves – it’s wild country, and making it back safely is solely up to you and the equipment you bring along.

No matter what mission you’re on, the vehicle you select is likely the most important decision involved.  Wetland vehicles are a special breed of off-road equipment that must excel in widely varying conditions, all while serving a multitude of challenging functions reliably and safely. 

A manufacturer of these wetland vehicles contacted Whitman Controls in search of temperature control solutions for their vehicles, protecting against heat-induced mechanical and hydraulic failures.  Motivated by a few of our client’s first-hand stories about what a night stranded in a marsh is like (we now know that panthers live in the Everglade marshes!), we pulled in our application engineering team and got to work.  


About Us

As a veteran-owned small business, Whitman Controls is dedicated to supplying premium quality, reliable, technologically advanced instrumentation for use in nearly any application.  Our Bristol, CT manufacturing facility embodies over 40 years of engineering, fabrication, and customer service expertise, serving both end-user and manufacturing customers nationwide through direct and distribution channels.  


Application Summary 

Wetlands are fairly common in the United States, requiring specialized vehicles to access and maintain.  Found prominently along coastlines, waterways (such as rivers), and water bodies (such as lakes), marshes are a type of wetland ecosystem featuring flooded land containing grassy, leafy plant life (as opposed to woody trees and plants that make up swamps). 

Marshes are of vital ecological importance to countless species and environmental processes, providing massive diverse habitats, natural water filtration, flood defense, and shoreline erosion control.  Accessing marshlands is no simple feat, requiring highly engineered vehicles that can both drive in loose, saturated soil as well as float in open water.  Wetland vehicles are used by a host of scientific, academic, conservatory, and government sectors to evaluate, monitor, care for, and maintain these lands. 

In addition, private landowners and business owners use wetland vehicles for their own purposes, including commercial, recreation, construction, sport, and tourism interests.  Wetland vehicles are used to transport people just as often as they’re used for specific tooling tasks, configurable with attachments such as mowers, choppers, pesticide sprayers, backhoes, boom cranes, geotechnical and environmental instruments, ditch diggers, and trailers.   



Just like with any automobile, high operating temperatures can lead to premature wear, performance losses, component damage, and even catastrophic failure.  Unlike most automobiles though, having a temperature-induced problem in a wetland vehicle can leave you miles from help in rugged conditions that you cannot simply walk through to seek aid. 

This is the exact concern our client sought to address in contacting Whitman Controls, specifically by looking for advanced instrumentation that would monitor and switch on when operating temperatures climbed too high in three systems:


1. Engine Cooling – this marsh buggy uses a custom diesel engine to drive its floating tracks, which sits below deck in a position where normal airflow and cooling options are limited.  


2. Propeller Hydraulic Cooling – in order to navigate the vehicle when on the float, a hydraulically-driven propeller is used to create thrust out of the rear of the buggy.  This system can see quick, high temperature climbs when pushing the vehicle through thick vegetation or when churning through stirred-up debris.  


3. Accessory Hydraulic Cooling – separate from the propeller drive, an accessory hydraulic system also requires active, responsive cooling for its own set of quickly changing temperature conditions.  Attachments such as lifting booms and power diggers can see temperature spikes when placed under heavy load.  


For all three systems, remote-mounted radiators are used to dispel heat to atmosphere.  Coolant and hydraulic fluid are sent up to these radiators, where electrical fans are used to move the right amount of air through the radiator cores to maintain a desirable operating temperature.  The challenge at hand was to select the right temperature input device that will engage these fans at the right time, able to stand up to both quickly changing marshland and onboard system conditions.  


“The most important quality that our customers look for [when buying a wetland vehicle] is that they can trust it to get them back to solid ground.  We put industrial-grade controls on our engines and hydraulics, making sure that temperatures stay low, nothing seizes, nothing overheats, every trip.” - Business Development Manager, Confidential Wetland Vehicle Manufacturer



Activating radiator fans based on input temperature is a routine application, but just as our customer suspected, selecting the right style and specifications of components would make all the difference between a reliable solution and a night in the marsh.  After careful review of each system at play, we determined that an inline temperature switch could be used to close a control circuit back to a fan controller, engaging the fans to push outside air through the cooling radiator to promote thermal exchange with ambient atmosphere.  

Selecting the specific sensor to use brought us back to thinking about all of the ways a marsh can present itself across the country.  We knew we needed an inline instrument that would directly contact hot coolant and hydraulic fluid as well as outside salt water (from rain and splashes), pushing us towards a unit with a Stainless Steel Type 316, NEMA 4 or better housing.  High system temperature compatibility upwards of 200°F was another critical factor, as was handling up to 850 PSIg internal pressure in the hydraulic systems.    

In this application, the electrical circuit had to be just as robust as the wetted circuit, needing super-simple two wire leads potted to the housing for maximum isolation, and able to carry a 1/2 Amp 12V DC relay load back to the fan controller.  Constant switching due to load spikes and load periods of time operating near peak temperatures were also called for, which could not be allowed to impact sensor reliability.  

Across all of these parameters, we ultimately selected the Whitman TP125 Temperature Sensor for the job.  The TP series met all requirements and then some, with the added bonus of only needing one part number to fit all of our client’s different vehicle, engine, and attachment systems.    



Whitman provided our client with an initial batch of TP-Series temperature sensors, which were promptly installed across all vehicles being built at that time.  Since this implementation, the TP-Series has earned its place as the standardized solution for all of our client’s vehicles and accessory systems, an honor we could not be more grateful to have received.  We are also fortunate enough to keep in touch with our client for ongoing projects and new product development efforts, but if you ask us, we’re really in it to hear all of the exciting stories about adventuring in America’s wild wetlands.  


Data Bullets 

•  100% vehicle overheating situation reduction 

•  15% increase in coolant and hydraulic fluid life due to lower operating temperatures 

•  0-1 weeks’ lead time on Whitman TP temperature sensors 

•  0% marsh buggies stranded overnight in panther-infested marshes due to overheating


Here at Whitman Controls, our values drive us to provide the highest level of servant partnership that you can find.  To discuss your applications or to learn more about our capabilities, please contact us at (800) 233-4401, via email at [email protected], or online at