Fluid Switch Blog

How to Stop Level Sensors from Failing

Level sensors are used in a number of different industries and applications to provide accurate measurement of liquids and other fluidized solids within a tank or vessel. Whether continuous or point value is set to be measured, their reliability makes level sensors a top option for keeping systems operating as intended.

What happens though in those occasional cases when tanks overflow or fluid levels get so low that a system breaks down? In these situations, and when it is discovered that a level sensor has failed, getting to the root of the issue and finding ways to prevent it from happening again is important.

First, let’s look at the reasons why:

Reasons for Float Switch Failure

One of the top reasons a float switch may fail has to do with poor maintenance practices. Normal wear and tear must be monitored and systems should be updated for optimal operating life. There are also application specifications and configurations to consider. Since no job is exactly the same, having a proper fitting float switch built from the right materials can make or break a design. Having the correct current conditions for shut down and steady state is also imperative.

Working with an expert team of engineers with experience in float switch design and application is a critical step in the building process. At SMD Fluid Controls we work together with customers to design a solution that works specifically within their requirements. Speak to a professional today!

Now let’s talk about protection from these issues.

Prevention Methods

To protect level switches from failing due to overcurrent conditions, proper wiring is needed. SMD Fluid Controls recommends tying the load and the switch as close as possible to the ground source to reduce any load spikes from traveling through the switch.

level sensor

As a precaution, you should also ensure that float switches are always mounted properly and that cables and connections are done accurately. These steps along with consistent cleaning and monitoring will go a long way in preventing level sensor failures from small production halts to those we read about in news headlines.

Contact us to learn about our custom design and manufacture services.



man afraid

5 Scary Overflow Scenarios a Level Sensor Could Have Prevented

It’s Halloween season and most everyone has horror on their minds. In keeping with that theme, we’re having a little fun with the blog this week. While level sensors and float switches are the answer to a number of problems faced by engineers and product teams, there are situations where a level sensor could have prevented an unsightly or dangerous mishap.

In this post, we’ll offer a few hypothetical, downright terrifying things that can happen when you don’t use a level sensor where you should.

  1. Chemical Processing Nightmares

Immersion heaters for chemical processing can burn out and fail if a system runs low or out of fluid before heaters are shut down. This can get downright dangerous and even become a fire hazard.

  1. Burnt Motors

In many industrial applications, level sensors work to monitor the level of water in tanks and warn when it’s low. Without them, pumps burn up and stop working due to low water or can cause the pump to cavitate. Depending what the pump is controlling, the result could be catastrophic.

  1. Ceiling Damage

Level sensors are also important for the operation of cooling systems and air conditioners in any space. Without a system to monitor and remove excess condensation and water, what results is a nasty, stained and damaged ceiling.

  1. Flooded Basements

Speaking of interior applications, basement sump systems that overflow when a pump fails to activate by a float switch or if the pump fails, can leave behind a big mess and lead to dangerous mold growth.

  1. Sinking Boats

This may seem extreme, but issues on boats where working mechanisms fail are actually quite common.  In this scenario, the worst case is that the bilge pump fails, there is no sensor in place and the boat sinks because of the bilge overfilling.

While the above terrifying scenarios are only imaginary, take a look at some of the recent news headlines and you’ll find headlines covering various industries – like a popular carmaker who’s engines are failing, food that is being spoiled or contaminated and a bunch of other mishaps and inspection failures. This is the reality for businesses that fail to plan and put sensors to work in their applications.

At SMD Fluid Controls, we want you to enjoy the Trick or Treaters and candy this season without the fear that your application could fail. Get in touch with our engineers for peace of mind. We have OEM and custom solutions to fit a variety of needs. Even if you’ve never thought about level sensors in your application, we can help you find a way to add their accuracy to your build.

Get in touch today!


What is a Vertical Float Switch?

A vertical float switch is a mechanical device that monitors liquid levels inside a reservoir tank. Regardless of the application, vertical float switches have one main purpose: to trigger an event when the liquid reaches a certain level.

What kinds of events can vertical float switches trigger? Refills, ceasefires, and discharges. Consider a typical dishwasher for example. Most modern dishwashers use vertical float switches as a backup for the fill timer. In the event that the timer fails to work properly, the float switch shuts the water off so that the dishwasher does not overflow.

How Vertical Float Switches Work

Vertical float switches are made up of two main components: a center tubed magnetic float and a reed switch. Both the float and the reed are operated by magnets. When the float reaches a predetermined level, the reed switch reacts by closing or opening.

In the dishwasher scenario, the float rises as the water fills; once the float reaches a certain level, it triggers the reed switch, and the process ends: the reed switch sends a signal to open or close (depending on how it’s configured by the manufacturer), and with that, water ceases to fill the dishwasher.

Common Applications

Due to their versatility and trustworthy design, vertical float switches are used by many different industries for a variety of different applications, like:

  • Boilers

    Like dishwashers, boilers require safety measures to work properly. If nothing existed inside the boiler to monitor and stop high water levels, then houses all over the country would flood. This is where vertical float switches come into play. The vertical float switch can trigger alarms that regulate pump controls, prevent overflow, and shut the system off entirely if extremely low water levels are reached.

  • Fish Tanks

    Water in fish tanks evaporate over time, and when water evaporates, salt is left behind. Unfortunately, even saltwater fish can only handle so much salt. Since fish can die from an excess of salinity in the water, fish tanks are often built with a top-off system that pumps freshwater in if salinity levels are heightened. Top-off systems use vertical float switches to automate the pump: when a risky amount of evaporation occurs, the reed switch closes, and the pump activates. Freshwater then gets pumped into the sump until the float switch opens. When this happens, the pump deactivates.

  • Water Wells

    Many water wells use vertical float switches to activate and deactivate well pumps. Two float switches are often used: one near the top of the tank, and one toward the bottom. The switch at the top cuts the electrical connection to the pump if the water level gets too high; the switch at the bottom connects to the pump if the water level gets too low. These two switches work simultaneously to keep the tank filled at an optimal level.

SMD Has The Right Vertical Float Switch For You

If you’re curious as to how a vertical float switch can meet your unique needs, then SMD has you covered. Not only do we manufacture a variety of different float switches, but we know these devices inside and out. We can also create custom applications based on your specific application needs. Don’t hesitate to contact us today. We will help you select the float switch that’s right for you.


engineer partnership

Partnering with Design Engineers on Custom and Standard Builds

The job of a design engineer is unique and often cumbersome. Across industries, they must rely on physics, complex scientific and mathematical techniques and sometimes even create something that’s not been done before.  Along with this inventive requirement, they’re also responsible for safety, meeting compliance and other standards all while doing this within a budget constraint.

That’s a lot to take on. By working closely with the manufacturing engineer and a team of designers throughout the product lifecycle and leaning on other experts in the industry, there is much benefit to be had. Cost and time savings and a product that works exactly as you intended it to.

After having researched and specified the requirements of the project and finding that there is a need to sense a liquid within the parts, calling on the experts at SMD Fluid Switch as a partner makes sense.

Here’s why.

We Do Level Sensing

We’ve been designing custom sensors to measure force, pressure, temperature, weight, torque, liquid level and many combinations of these since 1978. As a manufacturer and supplier of a wide variety of fluid switches, float switches, temperature gauges, and liquid level sensors. We have the experience in design and the integration of sensors into custom designs and can create solutions that meet your specifications.

These include machined level sensors, optical switches, ultrasonic level measurement, and custom molded float switches in metals or plastics like stainless steel, polypropylene, and nitrile butadiene rubber (NBR).

We Keep it Cost Sensible

We work to lower costs and increase productivity for all of our clients, offering competitive pricing for OEM designs and applications.

So whether you’re an automotive engineer and looking to add a fuel sensor to a gas tank, or a design engineer designing a countertop beer brewing machine and in need of water level management sensors, we’re here to help!

We Serve a diverse range of industries, including Aircraft and Aerospace, Alternative Energy, Boiler, HVAC and Air Handlers, Breweries and Wineries, Chemical Processing, Food Processing, Industrial Equipment, Marine, Medical, Oil & Gas, Specialty Vehicles: ATV, Farm Equipment, Water and Wastewater, and Manufacturing.

Engineers: Don’t go it alone when you’re designing a build. Get in touch today!


working on car

Reviewing Automotive Liquid Level Sensors & Their Importance

Liquid level sensors play an important role in the automotive industry. The safe and continued function of a car’s engine and other working parts depend on the ability for lubricants and other liquids to be measured, distributed and controlled at the right time and in just the right amounts.

In this post, we’ll overview the various automotive liquid level sensors that make it possible for drivers to get in, turn the key and go as well as the reasons many others are left frustrated and stranded in a car that doesn’t operate.

Fuel Filter Sensor

One of the most basic ways a car operates is by delivering gas to the engine. As the fuel makes its way through the gas line, a filter screens out any particles and dirt so it doesn’t get into the engine and cause issues like fuel pump failures.

With diesel engines, level sensors are an especially important component as the water that’s found in diesel fuel must be separated and kept away from the engine and other moving parts. The sensor will indicate when there is water that must be drained from the filter.

Oil Pressure Sensor

In addition to gasoline to get a motor running, lubrication of the internal parts keeps the wheels turning and things cranking. With proper lubrication, parts like the pistons and the crankshaft can move freely in the needed directions and aid the movement of the car forward.

Keeping the oil pressure at a dedicated rate also requires accurate and consistent measure.

Coolant level / Heat sensor

Coolant is the mix of water and antifreeze that’s used to keep the engine cooler while it’s running. It works by cooling the airflow under the hood. To reduce the heat happening inside the engine. A sensor used in this application provides a safety warning that your car is overheating.

As these sensors communicate with one another and detect an “issue” they activate a light on the driver’s dashboard to indicate something is off-course.  This prevents wear and tear and keeps drivers safe.

At SMD Fluid Controls we offer both continuous and point-level sensing solutions. From standard designs to custom options, we’ll help your needs get met. Get in touch to learn more!



Seasonal Focus: Customized Float Switches for OEM HVAC Applications

As the season’s change, outdoor temps will fall and many parts of the nation will see daylight hours shorten. Seasonal changes over the course of the year make HVAC functions important as they work to keep homes and buildings comfortable and safe for occupancy.

The fall season is when furnaces are started-up and heating in the home typically begins. Many areas will also soon be battling blustering cold temps and heavy snowfall.

OEM HVAC applications utilize customized tools to ensure equipment runs properly and efficiently at all times of the year.

Here’s a look at some of the ways customized float switches can be used in HVAC applications to assist with maintenance and to improve conditions.

Condensate Float Switches

Float switches used in condensate traps and condensate overflow pans in A/C units help with removing excessive moisture. During the summer months, these systems work in overdrive to cool homes. This can cause extra liquid condensate to form during normal operation.  During winter months, a condensate line can also become clogged or freeze due to low temperatures.

Even with regular cleanings, ensuring that extra liquid coming out of the cooling system is carried away safely is critical to keep your HVAC units running optimally. To aid with the normal operation of an HVAC system a float switch can be used to monitor the condensate trap or overflow pan that can send a warning and/or shut down the system so it does not cause unnecessary damage to property, damage or cause issues to the operation of the equipment.

A condensate float switch gets the job done.

Overflow & Drain Pans

A/C systems are designed already to handle liquid condensate, they come with a drain pan to collect the liquid expected to accumulate and direct it outside of the system.

Here, float switches can detect if that emptying is failing to occur before a backup causes the water to overflow back into the house resulting in water-damaged ceilings, walls, and floors.

A float switch can be used to activate a condensate pump when it detects higher than normal liquid levels.

FS31 Liquid Level sensor

SMD Fluid Controls’ The FS31 liquid level sensor is a low-voltage, condensate overflow shutoff switch that can detect level changes as small as ½ an inch and can be easily bracket-mounted in a liquid vessel to or in the top of a condensate pan for level detection.

It’s not just about cooling the home. In the upcoming colder months, HVAC applications should work intelligently to also ensure continual heat and hot water are being supplied.

winter house

Another application for a custom float switch is for controlling the automatic filling of supply water for outdoor wood-burning furnaces.

These energy efficient systems use a water-to-air exchange to deliver heat and are increasingly being used by homes and businesses.

Whether you’re searching for off-the-shelf solutions like the FS31 or want to add custom designed float switch solutions to fit specialty needs, SMD Fluid Controls can work with you to create an effective and efficient option that gets the job done.

Contact us today!

level sensor

How to Choose a Level Sensor

We speak frequently about the various applications where level sensing is used and how to best provide accurate measurements. But for this post though, we’ll be going back to basics to overview some of the most important things to consider when you are choosing a level sensor. After all, this decision will be the measure that keeps your machines and operations running smoothly and safely.

Step 1: Determine the Substance & What Must Be Measured

This is perhaps one of the most important factors in choosing a level sensor. Different liquids characteristics must be considered to make an accurate measurement. For example, highly viscous liquids like oils and grease can change the sensor requirements.

Other factors that affect monitoring a liquid level is factoring in if there could be build up in the tanks if it will be sticky or corrosive, and even the specific gravity of the liquid (the ratio of the object’s density to that of water).

In addition to the liquid being measured, you must also consider the tank that’s holding the material as its part of the larger picture.

For example, if there are limits to how the sensor is mounted to it, if the temperature inside must remain a certain degree or if there are pressure requirement or vibrating conditions that could possibly alter the accurate measurement, you’ll need to consider these factors in advance.

Determine if switching or continuous level monitoring is required for the application prior to making a selection. Also, submersible sensors placed inside a tank or those that are mounting externally are options you’ll need to choose from.

Step 2: Consider Conditional Factors

Outside of the most basic elements detailed above, you’ll need to also consider conditional factors that could change your options for level monitoring.

Can the contents inside the tank make contact with the sensor at all? Will it affect performance over time if so? Level sensor options will change based on these details.

  • Pressure sensors provide accurate measure using the measure of the bottom and open space within a tank.
  • Float switches work by measuring the level of a liquid based on its ability to float on the surface. They can be mounted vertically or horizontally and mounted on the inside or outside of a tank.
  • Ultrasonic level sensors use waves and echoes to measure a substances level and service.

Gathering as much information as possible will arm you with key information to make the best decision for level sensors.

Have questions? Need Answers? Speak to the professionals at SMD Fluid Controls. We can make recommendations, build custom solutions that work for you and help you feel confident you’re making the right choice for your application.


Custom Multilevel Sensors

Multilevel Sensors for Chemical Processing

Chemical processing plants are under stringent demands for quality and accuracy. These facilities also operate under unique environments where caustic fluids are present. One small inconsistency can easily result in a bad batch or even dangerous outcomes. To improve the measure of liquids at these facilities, level sensors are required that can be customized to fit different tanks and to be chemically resistant.

Choosing the right level sensor can improve quality and maximize output while also providing key real-time data on the liquids in vessels.

Here are some options to consider when it comes to multilevel sensors for chemical processing.

Direction & Location of Switches

One of the key considerations when choosing the correct level sensor for chemical processing is where and how it will be mounted. Both Horizontal and Vertical sensors mounted on top, bottom and tank level, can be made from a variety of materials depending on the chemicals used.

The FM10 & FM20 multilevel float switches are ideal for many chemical environments because they resist corrosion and can be used in restrictive spaces as well as handle high pressures and temperatures being used in many chemical applications.

Customized multilevel float switches can be used when you need precise monitoring of liquid levels in a tank while also saving space.

Early Planning Help

If your application will require a customized level sensor or float switch, but you’re unsure exactly what’s needed, the engineers at SMD Fluid Controls will work with you to design a fully customized multilevel fluid switch that does what you need it to, precisely and unique to your needs. Configure and customize switches and sensors work with up to six fluid levels.

Speak with an expert today!

Customized Sensors: Get the Fit You Need

Fluid sensors and level switches are used in a number of applications across industries to provide leak detection, overflow alarms, low-level warnings and even overfill shutoffs. In many of these cases, they are detrimental to operations and livelihood.

These sensors can be mounted on vessels in a number of different ways – top, side and back mounted, for example, depending on a number of factors. When used, they provide an accurate measure of the contents inside. Applications like agricultural machines, fuel delivery systems, chemical processing and so many others all make use of the sensors to operate safely and efficiently each day.

customized sensor

Sometimes though, basic won’t cut it. Standard sensors are great for so many reasons, yes. They help get the job done, offer protections and necessary advanced warnings -but what happens when you have a harsh environment, above normal heat requirements or serious dangers present?

At Fluidswitch we offer OEM customized versions of standard sensors so they can do what you need them to for your application.

Here are just some of the reasons why customizing sensors may be necessary:

  •           Safety Concerns

Depending on operating conditions and your specific application, you may require extra safety outside of the usual. In rugged applications or where discrete wiring and jackets on cables for volatile environments is necessary you may need a custom-designed sensor.  Our team will work with you to make sure your demands are met.

  •        Temperature Demands

For some applications, maintaining a certain temperature as well as liquid level in the vessel is critical. Think about bottling consumer beverages or chemical processing plants where accurate temperature maintenance will make or break an outcome. Fluidswitch can integrate both of these capabilities into a single unit to help you save space and resources while achieving the correct outcomes.

  •     Unique Batch Requirements

Another reason you may be wondering about customization for level sensors and float switches can relate to how large or small a job is. If you’ve taken on a load that’s not typical for your usual production numbers and you don’t want to over order unnecessary resources, no matter the quantity, SMD Fluid Controls will work with you no matter the quantity – large and small and get you the parts you need.

Have questions? Ask us about customizing parts to fit your needs!

Contact us today to schedule a consultation!


water management tank

Better Water Management: Level Monitoring and Pump Controls

Water is an essential element that’s used in a multitude of ways each day. Proper management is important for safety measures as well as conservation efforts. For this reason, there are a number of wastewater treatment options and monitoring systems that can be used.

In water towers for example, where water reserves are stored for droughts and power outages, maintaining proper water levels and pressure is critical. Then there are wastewater facilities, where there’s also an urgent need to monitor tank levels and have alarms that sound before an overflow situation occurs.

In addition to overflow dangers, there are issues like building up of matter on the walls of a vessel, sludge in the tanks and pressure loss that can all negatively impact water management.

Pump controls and level sensors added to these applications are a solution for accurately monitoring and helping to ensure water remains safely stored and separated.

SMD Fluid Controls offers pump level control options so you can regulate fluid levels and configure your tank system as needed. Using a pump or valve with a Double Pole Double Throw (DPDT) relay as well as float level switches combined with your product, we can help tanks to automatically pump up or down and keep your application running as needed.

Contact SMD to configure your application!