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My Hot Tub Is Not Heating Up: What Is Going On?

A hot tub that is not heating up correctly

Hot tub owners often look forward to the end of the day when they can unwind and relax as they step into the warm water. If you turned your hot tub on hours ago and it still feels lukewarm, you are likely left wondering why your hot tub is not heating up. What might be going on with your hot tub and how can you fix it?

There are a few reasons why your hot tub may not be working properly: clogged parts, broken switches, a malfunctioning thermostat, a broken pump or a faulty heating element.

Clogged Pipes Or Filters

Dirt, debris and leaves can make their way into your hot tub either because of the wind or sometimes on the bottoms of your feet. The filters throughout the hot tub help to keep the water clean and the experience enjoyable. But, if too much dirt enters the filters, there won’t be any way for water to flow through the tub.

That’s why the first place you should check if you’re experiencing a cold tub is the filters. Clogging is one of the most common problems that affect hot tub owners, and cleaning the pipes should be a part of regular maintenance. Thankfully, replacement filters are easy to purchase through your maintenance provider or at hardware stores.

Broken Pressure Switch Or Flow Switch

When the pressure switch detects that the flow of water in your hot tub is low, it will shut off the heater. Keep in mind that some models use a flow switch instead of, or in addition to, the pressure switch. Unclogging the pipes can send a message to the pressure switch to heat the tub again. If the filters and pipes are clear and the flow is normal, the problem may be your pressure switch or flow switch itself.

If this is the case, the pressure switch may need to be adjusted or replaced in order to get the hot tub heating again. Testing this part will require the use of a jumper wire. If you believe the pressure switch is broken or acting up, a professional is usually best equipped to troubleshoot the problem.

Broken Thermostat Or High Limit Switch

Similar to your air conditioner inside your home, the thermostat on your hot tub works to keep your water at your desired temperature. If the thermostat is broken, your hot tub may not be as warm as you would like. To investigate the problem on your own, check your thermostat to see what temperature the hot tub is “supposed to be”. If the numbers on the thermostat don’t match the temperature of the water, or the thermostat isn’t displaying anything, you might need to repair or replace it.

The high limit switch is another part of the hot tub that controls the temperature. If the temperature is too hot inside your hot tub, the high limit switch will prevent the tub from heating up even further. If you see an OH or HL code or see a red button popping out of your hot tub control panel, your high limit switch is working and has cut off hot water to your tub. Addressing this issue may require unclogging filters or cleaning the inside of your tub.

Pump Is Broken

Without a functioning pump, hot water won’t be able to reach your tub. If you reset your hot tub, it is easy to check and see if the pump isn’t working. Thankfully, replacing the hot tub pump is fairly easy to do on your own.

Heater Element Is Broken

Heating elements usually lie next to the high limit switch and pressure switch, and these components can be sensitive. Buildup from hard water or dirty filters can damage the heater element and cause the hot tub to stop working. If you reset the hot tub and it immediately stops, you might have to call a professional and get a replacement heater element.

Troubleshooting the tub may be the key to finding the problem and getting your hot tub water nice and toasty again. While it may be possible to assess the problem yourself, dealing with water and electricity can be very dangerous. Addressing malfunctioning hot tubs on your own can, in the most serious cases, put you at a higher risk of electric shocks, explosions and other serious accidents. If you’re not completely confident in your abilities, its best to call in an expert.

If you decide to take on troubleshooting your hot tub problems yourself, there are a couple of things you can do.

Troubleshooting common hot tub problems

Hot Tub Troubleshooting

So, let’s say you fire up your hot tub, and when you get in, the water is cold. What’s your next move? The first thing we recommend doing is covering the tub and waiting a few hours. The heater may just need time to do its work. If problems persist after this, however, you’re going to want to troubleshoot the tub.

To begin this process, reset the tub and watch for the moment when it stops working. At this point, there are a couple of different possible scenarios and questions you should ask yourself:

  • If the hot tub heats up but then stops heating, the problem could be the filters. Clean the filters before doing any other work on the tub.
  • If the pumps don’t turn on when you turn your hot tub on, they will likely need to be repaired replaced.
  • If the pumps are turning on but they aren’t moving the heat around the tub, you might have to unclog the pipes.
  • If you did clean the filters recently, the problem is likely to be the thermostat or heat sensors.
  • If nothing is working, the heating element might be broken and will need to be replaced.
  • If your hot tub is new, or are you just plain stumped, call in the professionals.

We had mentioned previously that you may need to reset your hot tub control panel to get your hot tub water warm again. But, what if you don’t know how to do that?

A malfunctioning hot tub which needs to have the control panel reset

How To Reset A Hot Tub Control Panel

We’ve already mentioned resetting your hot tub a couple of times as a way to solve some of your heater problems. But what if you don’t know how? The good news is that it’s really easy.

Just follow these steps:

  • Check your breakers and make sure they are flipped on. If you have a GFCI outlet, press the reset button to restore power.
  • Locate your hot tub’s high-limit reset switch. This is usually a red button found on a spa pack that is occasionally covered by a rubber nipple.
  • Press that button until you feel it click inwards.
  • Turn your hot tub back on and observe what happens next. Is water flowing? Is it getting warm?

Unfortunately, if this doesn’t fix your hot tub heating problem, there is probably an issue with your heating element.

A hot tub that isn’t heating isn’t the only problem that hot tub owners come across. Have you ever noticed abnormally low water levels in your hot tub?

A leaking hot tub

How To Find A Leak In A Hot Tub

Maybe your problem goes beyond the hot tub’s temperature. What if your hot tub is actually leaking? A leaky hot tub can do far more than kill the relaxing mood that hot tubs normally provide. Leaks near your electrical system put you and your family at risk of serious damage and even physical harm. Because of this, if you believe you may have a leak, it is vital that you locate it quickly and resolve the issue.

There are a few ways to find a leak in your hot tub:

  • Turn off the tub and look inside it. Wet pumps or pipes might help you determine the source of your problem.
  • Use food coloring to trace the leak. If the colored water appears on the shell, you may be able to point to the spot where it exits the tub.
  • Mark where your hot tub’s water levels are with a grease crayon or pencil, then fill the tub up with water. Let the tub run for 24 hours and then measure water levels again.
  • Finally, fill your tub up, let your hot tub sit for 24 hours and then measure water levels. If the levels drop the same amount, the leak is in the shell. If they differ, the leak most likely starts in the inside of the tub.

The good news is many problems that arise with hot tubs can be prevented with regular maintenance.

Hot tub maintenance tools

How To Maintain A Hot Tub

Any hot tub owner will tell you that you don’t stop paying for your hot tub after the initial purchase. Property owners also have to conduct regular maintenance to keep their hot tub working correctly. Thankfully, leaks, clogged pipes and many other problems can be prevented with proper maintenance. There are a few things you can do to maintain your tub on your own.

Keep Water Circulating

Newer hot tub models usually do this automatically. If you are not running water through your hot tub for at least 20 minutes each day, you may experience build up which can lead to damage. Run water through your hot tub daily to filter out dirt and debris. Doing so will keep your thot ub clean for when you’re ready to use it.

Put Tennis Balls In The Water

Dirt and debris are usually caught by your filter, and hot tub owners may not realize that tennis balls can actually help with filtration. Add a few clean tennis balls to your hot tub when you’re not in it. The fuzzy fibers can help to attract dirt and keep your water cleaner, without clogging up the filters. Tennis balls won’t substitute for clean filters, however.

Clean Your Filters

Speaking of filters, don’t forget to clean them regularly. Perform this routine tasks every week to keep your filters from getting clogged or becoming weak. Give these important parts an extra-thorough clean every time you drain the tub or close it down for the season. Also, remember that at some point your filters will no longer work. Cleaning them regularly will keep them around for longer, but at a certain point, you’ll need to consider replacing them.

Clean (And Drain) Your Tub

Clean both the inside and outside of your tub as often as you can. You can clean excess debris, dirt and leaves that are sitting at the top of your tub just how you would vacuum your pool using a pool skimmer. Many people don’t realize this, but debris and dirt on the outside of a hot tub can affect the inner workings as well.

Additionally, even if you’re consistently using hour hot tub, drain it completely at least once a season and give it a full scrub-down. The more you clean the tub, the less work the filters will have to do to clean the water for you.

Test Your Tub’s Chemical Balance

Once you fill your tub back up, make sure that your water’s chemical composition is correct. You should be checking the hot tub’s pH, cyanuric acid levels, alkalinity and chlorinity. Remember that you should also be testing these levels at the very least once a week to ensure your hot tub’s water is healthy for those who are taking a soak.

At this point, you may be realizing that a professional can help lighten the load them it comes to these ongoing responsibilities, as well as if you are experiencing some type of problem with your hot tub.

ABC Can Repair Your Hot Tub 

Learning about the different components of your hot tub, as well as having a firm grasp of the optimal chemical balance of your water, can feel like a part-time job. Instead of spending all your free time worrying about your hot tub, let ABC Home & Commercial Services take over. Our Certified Pool & Spa Operators have a thorough understanding of all the repair issues that pool and hot tub owners face. With ABC’s help, you can focus on enjoying a relaxing time in your hot tub’s perfect-for-you temperatures.

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