Category - Boilers
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Paul Holdsworth, Engineer

31 Jan : Updated 19 Feb ● 8 min read

5 reasons your thermostat isn’t working and how to fix them

As central heating systems get more and more advanced, increasing numbers of us are relying on thermostats to keep everything ticking over. They’re great little gadgets, allowing you to decide the exact temperature you want at any given time and schedule radiators to turn off and on periodically. But what happens when they stop working as they should?

Faulty thermostats can be a real nightmare. Your house might end up being too hot or too cold, and you could even find yourself paying more than you’d expect to on your heating bills. 

In this guide, we’ll walk you through some of the most common problems that you may encounter with your thermostats. Keep reading to learn how to troubleshoot successfully and get any issues fixed as quickly as possible.

Problem 1: Your thermostats won’t turn on

You’re pressing the on/off button repeatedly but nothing’s happening. Sound familiar? 

Thermostats that won’t turn on when you want them to are of no use to anyone. Luckily, the solution might be far more simple than you think!

Solution 1: Recharge or change the batteries in your thermostats

Okay, we don’t want to state the obvious here, but the solution might be as simple as changing the batteries! With many wireless thermostats being battery-powered, dead batteries mean dead thermostats, so it’s always worth keeping a spare set tucked away in a drawer somewhere for emergencies. 

Replacing the batteries isn’t just for complete blackouts; it can also be an effective way to fix thermostats that aren’t working as quickly or reliably as usual. If your thermostats are struggling to communicate with your boiler, try popping a fresh set of batteries in and see if that improves their performance.

Solution 2: Ensure the batteries are inserted the correct way round

This sounds too simple, but in some thermostat models, it’s not always clear which way round the batteries should be inserted. Double check that yours are in the correct way!

For more guidance on how to change the batteries in your boiler’s thermostats, check the manufacturer’s instructions; these will usually be inside their original packaging or can be downloaded online.

Problem 2: Your thermostats are displaying the wrong temperature

Another common problem with thermostats is related to their ability to give accurate temperature readings from inside your home. You might realise that something isn’t working as it should be when you notice your kitchen or living room feeling colder or warmer than the temperature displayed on your thermostat’s screen.

Solution: Clean or replace the temperature sensor

To fix inaccurate temperature readings on your thermostats, you might find something is blocking or covering the temperature sensor and it may simply need to clean any dust that has found its way into the device’s sensor or small vent usually on the top of the thermostat.  If your thermostat is remote or wireless entirely, it may be worth moving it to another location and see if the temperature changes as thermostats will only activate when the temperature of the room in which they are contained drops below the target temperature set.

If this doesn’t resolve the problem, you may need to replace the sensor entirely. This is a job that will likely need to be done by the manufacturer, so you’ll have to send the thermostats back for repairs to be carried out. Alternatively you may need to replace the entire unit.

Problem 3: The temperature of your heating keeps swinging from hot to cold

One minute you’re boiling hot and the next minute you’re freezing cold; annoying, right?! 

Temperature swings can be very stressful, especially if you’re just trying to have a relaxing evening at home with your friends or struggling to put a baby down for their afternoon nap! Beyond being a source of irritation, unregulated temperatures can also result in your energy bills shooting through the roof, as money is being spent on heating your home to unnecessary highs.

Don’t worry, though, the solution could be more straightforward than you might think…keep reading to learn how to stop temperature fluctuations in minutes.

Solution: Check the temperature settings of your thermostats

If the temperatures inside your home keep swinging between too hot and too cold, there’s always a chance that your thermostats have been programmed to turn your heating on and off according to a certain schedule. Check the time settings within the set-up section of your thermostats to identify if this is the case and, if so, adjust the schedule to one that’s better suited to your family’s needs.

Incorrect schedules can sometimes be pre-programmed into the thermostats or set up for you by whoever installed your new boiler. To avoid this happening in the first place, be sure to check with your engineer at the point of installation whether there are any time settings you should be aware of and ask them to walk you through how to change them if needed.  

Separately to this, there could be an issue with the boiler or system causing the heating to remain on or not turn off subject to demand.  Always consult a professional to help diagnose any unresolved problems.

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Problem 4: Your thermostats won’t communicate with your boiler

If your wireless thermostats can’t communicate with your boiler, they won’t be able to tell it to turn on and off according to your instructions. This means that you’ll likely find yourself in a situation where your heating is never on when you want it to be or it may mysteriously fire up without reason. 

If there is a communication issue between your thermostats and your boiler, it could be because you have installed new appliances or items of furniture into your home since installing the boiler which are now interfering with the wireless signals.

Common culprits are smart TVs, WiFi routers and extenders, games consoles and smart fridge-freezers; all of which operate using different frequencies and wavelengths that can interrupt those used by your home heating system. Additionally, large items of furniture such as wardrobes, fire doors and bookcases can cause similar problems.

Solution: Try repositioning your thermostats

Luckily, the solution might well be an easy one! In many cases, this problem can be solved simply by repositioning your thermostats to somewhere else in your home. Make sure that you choose a location that is relatively close to your boiler and not hidden away in a cupboard. 

Thermostats shouldn’t be placed immediately adjacent to the boiler or radiator, as the heat emitted by these can mess with their temperature sensors and cause them to flick your entire central heating system off sooner than needed causing other areas of the property not to heat up.

Problem 5: All of the above solutions have failed!

Sometimes, things just don’t go our way. It sucks, but don’t accept defeat yet!

If you’ve tried all of the solutions detailed above to no avail, it’s time to move onto the oldest trick in the book; turn everything off and on again! You’d use this tact with your computer, right, so why not with your home’s central heating system?

This fix has two stages; performing a simple restart of your thermostats and actually turning off your boiler itself. Let’s take a look at both of these in turn.

Solution 1: Restarting your thermostats

If you have Google Nest Learning Thermostats connected to your boiler, you’re in luck, as these are one of the easiest models to reset. Simply press and hold the ring at the centre for ten seconds before releasing. The thermostat’s screen should then turn a dark green colour and begin resetting itself. If the problem persists, try calling Google Nest’s support team on 808 169 2307.

If you have standard thermostats, this process might be as easy as finding the ‘reset’ button and giving that a press for between 3 and 5 seconds. This is the case with models like the ESi Wireless Room Thermostat.

Now, there isn’t a one-size-fits-all approach to this, as all thermostats are built slightly differently from one another. The particular way of resetting your thermostats will depend on the brand and model you have, so it’s always best to refer to the manufacturer’s instructions for accurate guidance.

Solution 2: Restarting your boiler

To perform a total system reset, try turning your boiler off and on again. This is usually done by locating the reset button on your boiler’s control panel and pressing it for no more than 10 seconds. It’s important that you only do this once before waiting for a few minutes to see if the boiler has fired up again.

Like with the thermostats, every make and model of boiler will be slightly different, so always refer to the manufacturer’s instructions if you’re in any doubt about how to restart yours. Or, for expert support from engineers who know their stuff,  get in touch directly with one of our BOXT experts using our Live Chat.

BOXT is here to help 

Here at BOXT, we took a good hard look at the heating industry and decided that it was time for change. House by house, boiler by boiler, we’re revolutionising the ways we heat and cool our homes, making it easier and more affordable for everyone to get what they need.