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What To Do When Thermostat And Boiler Not Communicating


So there is something wrong with the relationship between your boiler and thermostat, “What is wrong? Why aren’t they communicating?”

Unfortunately, the list of possible causes is quite long. However, we’re going to do our best to explain all the problems affecting your boiler and thermostat. Additionally, we’ll also tell you how to fix some of them.

Before we begin, you need to have a good understanding of thermostats and how they operate.

Thermostats are little separate boxes that help with temperature regulation. You just have to set your preferred temperature. The thermostat will then make sure the setting is attained and maintained.

Of course, we have smart and programmable thermostats that are more convenient than “manual” ones. With the help of AI, they can automatically learn your daily temperature routines and perfectly simulate them.

Types of thermostats

Boiler thermostats

As the name suggests, these thermostats deal directly with your boiler (Central heating system). Boiler thermostats are responsible for regulating the temperature of the water circulating through your entire system and radiators. In short, it determines the temperature of the water coming out of your taps. Of course, you can always adjust the temperature to your liking.

Room thermostats

Room thermostats control room temperatures. Ideally, each room should have its own thermostat. Flexibility is important (Especially if several people are living on the property). Nonetheless, it’s also possible for several rooms to share one thermostat. The only problem is, at all times, all rooms will have the same temperature.

When you set your preferred room temperature, you are rest assured the thermostat will keep the radiator running until the desired temperature is achieved. It will then switch off the radiator and wait for the temperature to drop below the set limit.

Boiler cylinder thermostats

Boiler cylinder thermostats are very similar to boiler thermostats. However, as you might have guessed, they’re location-specific. Instead of generally regulating the temperature of all the water flowing through the system, they only deal with the hot water cylinder. This is water you get when you open your showers.

Once you’ve set your preference, it will fire up the boiler until the water in the cylinder is at the right temperature. It will only turn on if you use most of the water in the cylinder or if the water temperatures naturally fall.

Note: Your boiler cylinder thermostat must be working perfectly. If it’s faulty, you can get seriously burnt (If it allows the water in the cylinder to get heated way above “healthy” temperatures). For extra safety, we advise you to install thermostatic mixing valves.

Signs your thermostats isn’t working

Cold radiators

Your boiler is working just fine. However, there is something wrong with your radiators. They’re too cold.

Most of the time, it might be that your room or boiler thermostats aren’t communicating with your central heating system. Maybe your thermostat settings have suddenly changed without your input. This is a common occurrence, especially after a power surge. If the thermostat setting is too high, it won’t prompt the boiler to heat your room.

In the worst the case scenario, your thermostats might be dead or knocked out cold.

Very hot/cold shower and tap water

We all treasure hot showers after long days of hard work. Nevertheless, there has to be a balance. Too hot, and we’ll end up losing our skins. If your boiler thermostat loses control, your bathroom routine might turn into a hell experience.

It might be that your thermostat is not communicating well with your boiler. In this case, it’s allowing the boiler to heat the water to unhealthy levels.

The cause is also similar if you’re experiencing unusually cold water. Chances are, your boiler settings might have changed without your knowledge. Likewise, maybe your boiler has crashed and needs repairs or replacement.

We researched and found out that thermostats tend to crash during Autumn as we approach Winter. For some reason, thermostats disappoint after staying dormant during Summer.

How to restore the thermostat-boiler connection

Fortunately, you don’t always have to call the professionals. Below are some of the ways you can fix the problem yourself.

Check the thermostat batteries

We know you are like, “Really? That’s the best professional advice you can offer?”

Calm your radiators. We know it sounds too obvious to be true, but trust us, it’s a common problem. After the long summer spell, people forget that their wireless thermostats run on batteries. Here is a fun fact, “Batteries don’t last forever.”

It wouldn’t hurt to at least replace your thermostat’s batteries and see what happens. Who knows? You might end up saving the money you’d have otherwise spent calling heating professionals.

Restart your thermostats

If you do it with your computer, then why don’t you try it with your thermostats?

Restarting your thermostats will help reconfigure some settings that might be hindering that “perfect” connection with your boiler.

It’s simple. All you have to do is turn off your thermostat, remove the batteries, leave it for around 10 minutes, and then turn it on (With the batteries, of course).

Still not working?

Turn up the heating

Set your thermostat to a much higher setting than usual and give it some time to respond. Maybe the boiler isn’t responding because the temperature setting is too low to trigger the thermostat.

After about 15 minutes, walk into the room or touch your shower water.

Is there any change?

Yes? Then your settings are the problem.

No? Stay strong and move to the next step.

Reconnect to your boiler

We’re asking you to try and reset the connections between your thermostats and your boiler.

Of course, they are many models in the market. We can’t give a one-fit solution for all of them. In this case, you’ll have to consult your thermostat’s user guide. We’re sure that most of them have a troubleshooting procedure that addresses this particular problem.

Don’t have the physical copy? Most manufacturers have uploaded a digital copy on their websites.

Still can’t find it? Go ahead and google, “How to reconnect (Your thermostat’s brand and model) to my boiler.”

Relocate your thermostat

This solution works for room thermostats. Sometimes, you might have to move your thermostat to a different location.

We know what you’re thinking, “Why move it when it was working well just a few days or weeks ago?”

Well, chances are, you might have installed new appliances or furniture. These new additions might be creating interference that is hindering the connection between your wireless thermostat and boiler. We’re talking devices like Smart TVs and routers, among others. They all have different frequencies and waves.

Although it’s wise to position the thermostats somewhat closer to the boiler, it’s never a good idea to keep them too close. The heat from the boiler might mess with the thermostat readings. Also, don’t install them far apart from the boiler. As a rule of thumb, your thermostats should be 30 to 50 meters within the boiler.

Are they still not working correctly? Hold on. We have another step.

Check your boiler timer and central heating programmer

The boiler timer is responsible for turning on the boiler at specific times of the day according to your heating schedule. Some are manual, and others are automatic.

On the other hand, the central heating programmer does the same but on different days. There are two main types of central heating programmers, single-channel programmers and twin-channel programmers. For those with dual systems, they allow you to either heat your homes, water only or both.

Maybe your thermostat isn’t responding because of either a faulty timer or programmer. The two tend to crash after power surges. To fix the problem, you might have to reset them. To get the procedure, you can either consult your user’s guide or check on the internet.

Reset your boiler

This is the final draw.

If everything fails, carefully reset your boiler and see what happens. Your boiler might be the culprit. Most boilers have a reset button. If you’re in doubt, pull out your user’s guide.

Call a Gas Safe engineer

Unfortunately, some of you might reach this stage.

There is nothing more you can do. You’ll have to call the professionals and have them diagnose your system.

Note: Don’t attempt to fix the boiler on your own. It’s scary and dangerous work.

We hope that this guide has helped you if your thermostat and boiler aren’t communicating. Don’t forget. We’re here to help with all your boiler-related problems.

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