Why is my heating not working?
Switching on the boiler to find the heating not working is not a great way to start or end the day.
If you’re experiencing this issue, you’ll be pleased to know that there are some steps you can take to diagnose and potentially fix the problem without having to call in a professional. By following the troubleshooting guide outlined below, you can save yourself time, money, and hassle.
Why is my heating not working?
Fault code displayed on the boiler
Faulty zone or diverter valve.
Why is my heating not working?
Your heating works by a straightforward process.
- You turn on your timer and thermostat (create a demand)
- Your thermostat checks to see if the temperature is low enough to come on.
- If the temperature is low enough the thermostat sends power to the boiler or diverter valve.
- The boiler fires up until it reaches the correct temperature or there is no longer a demand.
No demand
Central heating is usually controlled by a timer and a thermostat. You may have both, a combined programmable room stat or you may have neither.
Whichever combination of controls you have the boiler needs a demand before it will start to work.
A demand is usually shown on the display of the boiler as a radiator symbol. This can be a picture that flashes on the display or a light that illuminates beside a picture printed on the boiler case.
However,, plenty of boilers don’t show if there is a demand. The only way to tell is to turn your timer to constant and your thermostat to maximum. With the controls definitely set to on you should hear some noise of pumps or fans running. If not there is either no demand or the signal isn’t getting through to the boiler.
Thermostat is set too low
If your room thermostat is set too low the heating will not come on.
This is a surprisingly common reason for a breakdown.
Most of the time this happens in late spring or early Autumn. On unusually sunny days the house might be warm enough that the heating doesn’t come on at its usual time.
Turn the thermostat to maximum then check the boiler. If the heating is now working the thermostat was set too low.
Timer turned off
Most timers have a light that illuminates when the timer is on. If the light is on there should be a demand.
Fault code displayed on the boiler
If there is a fault code displayed on the boiler it will not fire up to heat your house. Go to our boiler faults page or look at your manual to find the right fault code.
Faulty zone or diverter valve.
If you have a hot water tank or two thermostats in your house you will have most likely have a zone valve or a diverter valve.
This valve controls your heating and hot water and can cause the heating to not respond to the controls.
It is normally in the hot water tank cupboard but can be hidden anywhere in the house. They are normally on show but can be hidden behind false walls or under floors.
They look like a pipe with a metal or plastic box attached to it.
There are electrical controls in the box on top that can be faulty and the valve underneath can stick so it’s a mixture of two potential faults.
The metal head (the box on top) can be changed by itself and is normally the cause of the heating not working. However, the bottom valve part can seize up and break the head requiring the whole valve to be changed. Replacing a whole valve is normally the job of an experienced heating engineer.
Boiler turned off
If there are no lights on the front of the boiler there is a small chance the boiler has been turned off by accident.
You would be amazed by how many people have waited for hours (sometimes overnight) in the cold only to be told their boiler was simply turned off at the power switch.
There will be a fused spur, a single switch with a fuse holder, near the boiler although sometimes they can be not. In older houses, the fused spur and power supply could be from a previous boiler located somewhere else in the house.
It should be left on all the time even when you aren’t using the boiler.
Summary
During extreme winter weather, your heating not working can be an emergency. By following these tips, you may be able to quickly fix the issue and save money.