Radiant Floor Heating Not Turning Off? 5 Possible Causes

A radiant floor heating system's layout

Your radiant floor heating is not turning off, and you’re trying to figure out why?

You’re not alone! This is something that affects thousands of people with this heating solution every single day.

I know that having your main source of heat can be very frustrating, especially during cold nights when you’re looking for coziness and relaxation.

But don’t worry, you came to the right place for answers. Below, I’ve prepared a small list including the 5 most common causes behind this issue, and some easy ways to solve them.

When your radiant floor heating is not turning off, it might be due to a faulty wall thermostat, the wrong temperature settings, or damage to the tubing. This situation could also be caused by bad zone valves or improper insulation of your flooring.

Keep reading to stop the heat!

#1 A Faulty Thermostat

Let’s kick this off by making sure that one of the most important parts of your radiant floor heating is not failing terribly.

When you got this heating solution installed, whoever did the job might have explained to you what the thermostat does; however, if this is not the case, or if you moved to a home where this system was already installed, please read on.

In a nutshell, a thermostat is a component of your appliance that both measures and regulates the temperature that the floor produces. It’s through this device that you can set your desired temperature and keep it steady for as long as you want.

A thermostat being adjusted
A bad thermostat could be keeping your radiant floor heating system from turning off

Thermostats these days are very precise and quite durable, but they’re neither failproof nor indestructible. If your radiant floor heating is not turning off, it might be due to something wrong with this component.

If your thermostat is not reading the produced temperature as it should, it could mistakenly keep your heating system on, even when the floor is already at the temperature you wanted, thus causing this situation.

Solution: This can happen for many reasons. Sometimes, the thermostat itself is failing, and you’ll need to replace it. But on other occasions, there might have been improper cable placement during installation, or after certain repairs.

First, I’d recommend checking on the thermostat’s control panel, which should be located on one of the walls in your home. If you already tried to mess with the heating settings, you know exactly where it is. Here’s what you should do to look for problems:

  1. If possible, cut off power to the section of the house where the thermostat is located to prevent electricity-related accidents.
  2. Once you’ve located the thermostat control panel, try removing the plastic plate that’s hiding its screws.
  3. After exposing the screws, carefully remove them and keep them somewhere safe.
  4. Remove the thermostat from the wall while making sure that you’re not twisting or pulling on any of the cables connected to it.
  5. If you have your thermostat’s user manual, find the page where the cabling layout is shown to compare it to what you have and make sure everything’s connected properly.
  6. Provided it is, then you might want to go to your basement (or where your radiant floor heating’s control center is) and make sure that the thermostat cable that goes into it is also connected properly.

Assuming everything looks normal, chances are the thermostat itself is failing, in which case, you’ll need a new one. Since this component must be configured and connected to your radiant heating system’s control hub, I’d recommend calling an expert to take care of this.

Note: If you’re unsure as to what thermostat you require or need the cabling layout for your specific model, you can go to Google and search for “<Your Appliance’s Make And Model> User Manual>”.

#2 You’re Using the Wrong Settings

So, you’ve checked your thermostat from top to bottom and everything seems to be okay, yet you’re still experiencing uncomfortably hot temperatures. What now?

Well… now, we make sure that you’re using the right temperature mode.

Many thermostat models come equipped with both Fahrenheit and Celsius configurations to meet the needs of several customers around the world. And while this should have been dialed in the right way when the heating system was installed, human error is always a possibility.

Now, this should only be an issue if you’re accustomed to using Fahrenheit degrees and the thermostat is set to Celsius, as the opposite scenario would simply leave you with a cold floor. But if you’re setting what appears to be a nice temperature, and the room gets extremely hot instead, chances are you need to look under your thermostat’s “hood”.

Solution: Depending on the model you own, the temperature variant might or might not be displayed on the device’s screen. If it is, just take a closer look and try to determine which setting you’re currently using. Once you have a clear answer, check your User Manual to find out how you can change the Metric system and set the Imperial one instead.

Provided your thermostat does not have this option, please follow the steps from the previous point to detach the component from your wall and access its back circuitry. Once you’ve done that, try the following:

  1. Your thermostat’s backside should have circuitry with a bunch of cables and soldered diodes.
  2. Try looking for a set of switches that can be flipped.
  3. Find a legend that says “C/24” and “F/12”. If the switch is flipped to the left, the thermostat is set in Celsius, and if it’s on the right, it’s working on Fahrenheit units.
  4. Flip this switch according to your needs and reassemble the component.

Note: This might not be an option for all thermostat models out there. If you have any doubts regarding your specific unit, please refer to your User Manual.

#3 Damaged Tubing

The next possible reason why your radiant floor heating is not turning off is damage to the tubing that helps hot water flow throughout your home.

As you know, effective use of this appliance comes from water passing through a boiler that heats it up for later distribution throughout the pipes in the system. This creates rising temperatures that make your entire house cozy and comfortable.

And while radiant floor heating systems can be a blessing, they’re also very sensitive to any kind of issue present on them.

A radiant floor heating system's PEX tubes layout
Broken PEX tubes can cause water and heat leaks

If you notice that, even after telling the appliance to stop heating, it keeps on working, chances are there’s a damaged tube somewhere below you. Partial or total tearing of one or more of the PEX tubes can cause dangerous leaks that might not only increase moisture in your home but also affect how your appliance works.

An event like this could explain what you’re currently experiencing, as hot water remains on the floor rather than being circulated everywhere.

Solution: Addressing this situation might be a little tricky for non-contractors, as you have to spot where the leak is before you can even start thinking of patching it up. There are devices out there called Thermal Imagers that can help you spot the leak without breaking ground, but they’re not at all cheap.

A leak is especially likely if you notice that only one area or room in your home seems to not be turning off the heat. So, if you notice this, waste no time and call a professional as soon as possible.

#4 Bad Zone Valves

Moving on, let’s talk about zone valves, what they are, and how a faulty one could explain why your radiant floor heating is not turning off.

In their most basic form, zone valves are components that control the flow of water to every area of your home. When you set your system to heat up, they stay open, and water makes round trips around your living spaces. And when you turn the heating off, they close completely.

Zone valves are very useful in controlling very accurately how a radiant floor heating appliance works; however, when one or more fail, problems soon follow.

A home's zone valve main control hub
Zone valves are the backbone of your radiant floor heating system

A damaged zone valve could be having trouble cutting off the flow of water to a certain area of your home, keeping it warm all day long. This could trick you into thinking that the entire system is failing and refusing to heed your commands.

Solution: First, you’ll need to identify the faulty valve. As mentioned in the previous section, you can use a Thermal Imager to do this. Turn your radiant floor heating system off and use the Thermal Imager to find the culprit.

Replacing a faulty zone valve is a very complex and long process that requires a lot of experience and specific tools, so for your safety and that of your heating system, I’d recommend calling a professional to do it.

#5 Improper Insulation

Lastly, let’s make sure that your flooring is properly insulated.

You might be wondering why this is important, and the simple answer is – heat preservation. In order to deliver the results you want, your radiant floor heating system relies on the heat passing through the PEX tubes (cross-linked Polyethylene).

Under normal circumstances, the heat radiating from said tubes heats up your floor and the entirety of your home, and the system shuts off when the desired temperature is reached. However, if your floor is not properly insulated, the generated heat can escape through tiny cracks, making it impossible to preserve heat.

This does not only mean that your radiant floor heating system will likely keep running for longer than it should, but also that you’ll be paying excessively high utility bills for no good reason.

Solution: The best and quickest way to tell whether your floor is not properly insulated is by using the Thermal Imager mentioned above. This device can easily show you where there are hotter and colder spots, which can be very useful, as the latter will likely mean there is a heat leak.

Now, as I mentioned above, good Thermal Imagers don’t come cheap, so if you don’t already have one or can’t borrow one from someone, you might want to call a professional with the right tools.

More often than not, insulating your floor is not too challenging, as you’ll just have to either replace the foam under it, or replace any other insulation material that’s being used. Once you’ve dealt with this issue, your radiant floor heating will work much more efficiently, and will turn off when you tell it to.


That about covers it.

When your radiant floor heating is not turning off, what should be a comfort-giving appliance can turn into one of the largest inconveniences within your home.

Luckily, as I hope this piece has helped you see, addressing the most common causes behind this situation can be very easy and quick. In most cases, simple actions, like double-checking your temperature settings, and making sure that the thermostat is working normally, should do the trick.

Thank you so much for sticking with me all the way to the end. If this article piqued your interest and answered your most burning questions, you’ll be glad to know that there’s more content to learn from below.

On the site, you’ll find all sorts of solutions and information on everyday appliance issues, such as a fridge door that won’t stay closed, or a stove that keeps tripping your breaker.

Have a great week!

— Craig.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more