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7th June, 2024

How to Fix a Boiler Not Responding to Its Thermostat

How to Fix a Boiler Not Responding to Its Thermostat

When your boiler isn’t responding to its thermostat, or vice versa, it can be tricky to identify the problem.

In this guide, we’re going to take a look at why your boiler and thermostat aren’t communicating and how you can get it fixed.

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Why Isn’t My Boiler Responding to Its Thermostat?

Usually, if you find that you cannot control your boiler from the thermostat, it is either one of two components that isn’t working.

To work out what the problem is and how to fix it, you’ll need to identify which one is experiencing the problems. 

To begin with, you should clear some of the basics which could be causing your heating problems.

Checking the Boiler Basics

Make Sure Your Boiler is Turned On

Whilst this might seem like a ridiculous and somewhat patronising suggestion, you would be surprised by how many customers pay a hefty call out fee for an engineer to come to their home simply to tell them their boiler was turned off the whole time.

Make sure your boiler is turned on at the appliance itself and at the mains.

Boiler Turned On

But I haven’t turned my boiler off!

It’s still definitely worth a check- power cuts can often cause your boiler to switch off and not automatically come back on, or you may find that another member of the household has been fiddling with switches.

Replace Old Batteries in Your Thermostat

As with any battery operated device, if you have a wireless thermostat you’ll need to replace its batteries every now and then. 

Usually, your thermostat will alert you that the batteries need changing up to a month before they run out with either a message on the digital screen or with a flashing light somewhere on the device.

Replacing Batteries

When the low batteries eventually die, you’ll see a black display screen and the thermostat will stop working, meaning your heating system will go down as there is no temperature command being sent to your boiler.

Relocate Your Thermostat

In order for thermostats and boilers to work, they need to be able to communicate well with each other. 

If your thermostat is located nearby the boiler, another heat source or a poorly insulated area of the home that doesn’t represent the temperature of the rest of the home, temperature readings can be inaccurate and end up causing your heating to come on when you don’t need it or not come on when you do.

Relocate Thermostat

If this is the case, you may need to relocate your thermostat so it can get more accurate readings. Thankfully, if your thermostat is wireless then this should be a very simple task. If your thermostat is wired in, however, you may need to arrange for it to be relocated by an electrician.

Make Sure You’re Inputting the Instructions Properly

A thermostat allows you to have full control of your heating, however, if you don’t know how to work your thermostat properly, how can you expect your heating system to know what to do?

Make sure you are programming your thermostat correctly and setting the temperature above the threshold in order to turn the heating on as when the temperature you set is too low, it may not trigger the heating to come on.

If you find that you are unsure of how to use your thermostat properly, most manufacturers have instruction leaflets or manuals you can find online.

Should I Opt for a Smart Thermostat?

Modern smart thermostats can be much easier to work and can often be done through an app on your phone, helping you to stay more in control of your heating.

It’s also worth mentioning that smart thermostats can learn your household heating behaviour and work automatically e.g. turning on ten minutes before you usually arrive home from work as well as a range of other fantastic benefits. 

Check out our list of the top smart thermostats in 2021.

I’ve Tried Everything and It’s Still Not Working!

If you have covered all of the basics and your boiler and thermostat still aren’t communicating with each other, it may be time to call in a Gas Safe engineer to take a look for you

Replace Your Broken Boiler

If you have covered these basics and your boiler and thermostat still aren’t communicating as they should, it may mean your boiler is not working properly. 

Replace Your Boiler

This could be due to a number of reasons. You can find some of the most common boiler problems and how to fix them in our helpful guide.

If your boiler is over fifteen years old, it may be on its last leg and struggling to respond to your thermostat. 

Unfortunately, this means it is likely time to say goodbye to your old boiler.

How much does a new boiler cost?

The answer to the question - how much is a new boiler? is well - 'it depends'.

Effectively, new boiler cost can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and boiler installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap

£1,845

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System to combi conversion

£2,499

Get a quote

New boiler install

£2,899

Get a quote

Back boiler to a combi

£3,299

Get a quote

System to system

£1,945

Get a quote

Brand New Boilers + Install with iHeat

Fortunately, you can get a brand new boiler that will be significantly more energy efficient and help you save up to £380 a year on energy bills, making it an incredibly worthwhile investment.

Boilers with iHeat

Not to mention, most modern boilers are compatible with smart thermostats, unlike very old boilers.

Get a brand new A-rated efficient boiler plus install today with iHeat and get a free wireless thermostat.

For more help and advice, why not check out our other helpful blogs and boiler guides. Including a great detailed guide on our best combi boilers.

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Frequently Asked Questions

Why isn't my central heating thermostat functioning?

There could be several reasons for a central heating thermostat not functioning, such as:

  • Power issue
  • Dead batteries
  • Incorrect settings

First, check if the thermostat has power and replace the batteries if necessary. Ensure the thermostat is set in the correct mode (heating) and that the temperature is set high enough to trigger the boiler.

How can I check if my boiler thermostat is working correctly?

To check if your boiler thermostat is working correctly, follow these steps:

  • Ensure it is set to the appropriate temperature.
  • Gradually increase the temperature setting and listen for a clicking sound, which indicates the thermostat is triggering the boiler.
  • If the boiler doesn't respond or there is a significant temperature difference between the setting and room temperature, it might be a faulty thermostat.

What should I do if my thermostat isn't communicating with my boiler?

If your thermostat isn't communicating with your boiler, follow these steps:

  • Ensure it's correctly wired and powered.
  • If the issue persists, check for any damage to the wiring or the thermostat itself.
  • You can refer to the manufacturer's guidelines or consult a professional technician if needed to resolve the issue.

Why does my boiler keep running when the thermostat is off?

A boiler running when the thermostat is off could be due to:

  • A faulty thermostat
  • A wiring issue
  • A problem with the boiler itself

First, double-check the thermostat settings and ensure it is off. If the issue persists, inspect the wiring for damage and consult your boiler's manual for any specific troubleshooting steps.

How can I resolve issues with specific boiler brands not responding to thermostats?

For specific boiler brands not responding to thermostats, it's best to:

  • Consult the boiler's manual or the manufacturer's guidelines for any unique compatibility or troubleshooting tips.
  • If the issue persists, reach out to the boiler's manufacturer or a professional technician for assistance.

How do I restore communication between my thermostat and boiler?

To restore communication between your thermostat and boiler, follow these steps:

  • Check the power source and wiring.
  • If the issue isn't resolved, you might need to reset both the thermostat and the boiler. Consult the manufacturer's guidelines for proper reset procedures.
  • If the issue still persists, consider professional assistance to inspect and resolve the problem.
Stephen Day profile photo
Article by
Stephen Day

Co-founder

Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.