Why Is My Heating Not Working ?How To Fix It?

Picture of a man warming hands over a candle due to no heating | Letsgo TNT Gas & Heating Engineers

Heating Not Working?

There is nothing worse than turning on the boiler and nothing happens. No hot water and heating not working is not an ideal situation especially when it’s cold outside and the winter has only just started. ! Why does this happen? Before you panic and call a heating engineer, try these 11 easy steps before you make that phone call!

1: Check other gas appliances

Heating not working? If you have any other gas appliances in the house, check them first to see if they are working. If they are not, chances are its not the boiler. If you have a prepaid meter, it might be out of credit so check that before you look elswhere. Don’t rule out your local gas maintenance workers operating in your area and they have turned the gas off.

They are supposed to inform people in the area but it’s worth a try checking to see if anytone is working on the gas supply outside.

2: Check the electrical power isolator to the boiler

If the boiler is showing no display, it could well be that there is an electrical issue. Go to the main control panel and see if you can locate the heating isolation switch. If it has tripped, that is what most likely is the reason that your heating is not working. If however, the isolation switch hasn’t tripped, unless you are competent with electrical issues, it is best to leave it to the professional. Contact your local heating engineer to diagnose the problem.

fused spur

3: Check your pilot light

Heating not working and your boiler has a permanent pilot light, you will need to check the boiler manufacturer’s instructions on how to relight it. If you are unable to relight it or don’t feel confident on how to do this, have a heating engineer look at this for you. Any persistent pilot light issues should always be checked by a Gas Safe Engineer.

4: Switch boiler on and off

Heating not working? Before calling out a heating engineer, it might be worth turning the boiler off for a few seconds then switch it back on again to see if it fires up. This can happen. The boiler switch is normally near the boiler. If not, sometimes it is fitted in an airing cupboard or even in the kitchen.

5: Reset the boiler

The boiler’s reset button should be located somewhere on the front panel. If you can’t locate it,  check your boiler manual for instructions on how to reset it as every boiler is different. If the heating is not working after resetting, you most likely have other issues that will need a heating professional to diagnose.

boiler reset button

6: Frozen condensate pipe

There is a white plastic waste pipe that comes out the bottom of the boiler and if it runs externally, it could well be frozen. No need to panic as this is a simple fix. Either use a hairdryer and run it up and down the pipe outside the external wall to where it goes into the ground. If the heating is still not working, keep applying heat to the pipe until it does work.

Keep heat on it for a few minutes then go back inside the house and reset the boiler and it should fire up. If you don’t have a hairdryer, boil a kettle and pour hot water over the external pipe a few times and that should unblock the ice.

7: Check room thermostat

Before you panic, go to the room thermostat and see if it is turned on. Check to see that the temperature setting is higher than the air temperature in the room where your thermostat is located. If it is not, turn it up higher and the boiler should fire up. Another issue could be low battery power.

There is normally a low warning indicator that flashed on/off which means you will need to replace the batteries. Once you have done this, the boiler should start. Heating not working?  Another possibility is that the heating demand has been satisfied and the boiler doen’t want to fire up. This is because the room thermostat has sent no signal to the boiler to turn it on.

8: Temperature dial

Your boiler will have two dials on the control panel. One is for water temperature and the other one for your central heating. if the dial is on minimum, the boiler will not fire up. Turn the dial to nearer maximum and it should start.

boiler temperature dials

9: Boiler pressure

Heating not working? Something that is often overlooked is checking to see if the pressure in the boiler is sufficient. If the pressure is in the red zone, your heating will not work. If there is an auto  filling loop located directly underneath the boiler, you can pull the lever and you will hear water going into the heating system.

Once it has reached a certain level, normally minimum 0.7 bar or so, you will hear the boiler fire up. there is another type filling loop that is normally lower down the pipework and has a longer braided hose. Turn both levers open and you will hear water enter the heating system and it should start. Don’t forget to turn the levers closed again.

10: Check the timer settings

Depending on what kind of timer controller you have for your heating, check to see if it is set to auto. This would indicate that it has been set to come on at certain times of the day and the boiler wont start until the set time has come. Heating not working? If you press the heating button near the bottom of the timer and set it to on or once, the boiler should fire up.


11: Diverter valve stuck

Heating not working and you have tried all of the above tips? Then it is most likely the diverter valve that has stuck, This normally happens when people turn off their heating for the summer months and when they turn the heating on for the first time in 5 or 6 months the heating is not working

We always recommend to our customers to prevent this from happening, turn on your heating a few times though the summer months to keep the diverter valve moving and this normally prevents it from sticking.

Unfortunately this is not something that you will be able to fix. You will need a gas safe registered engineer to either take it out and try moving it or possibly replace it. We are here to support you should you need our help.


We hope that you got some value from this blog and would appreciate if you could like and share it with friends on Facebook. Your feed back is also very welcomed!


Heating Not Working?

Download Our Guide

New Client?

Get 1st Exam
For Free