What to do if your gas heating won’t go on

The steps we would go through

Most of us have experienced a time when our heating didn’t go on and we were a bit confused. This can happen for several reasons.

Here is what we would do…

Check the programmer

We would check the heating programmer to ensure the correct time was set because, if the programmer is set to go on and off at different times, it would be out of sync if the current displayed time is incorrect.

We would also check the setting on the programmer. If it is set to OFF, then obviously the heating would not be on. If it is set to AUTO or ONCE, then checking the times would be useful. If it is set to ON and there is sufficient pressure for the boiler and there is no fault code displayed, we would check the meter.

Check the boiler

Most modern boilers display a fault code if there is a problem with the boiler. If we looked at the boiler, and saw a fault code, we would then go to the boiler fault code pages on this website to find out what the problem is. If the information for your boiler is not listed on our pages, please let us know and we will add it.

We would also check the pressure on the boiler because a boiler may stop working if it does not have enough pressure. If this is the case, we would either increase the pressure ourselves or we would get a boiler engineer to do this for us. If you are not sure, please speak to the landlord of the property or, if you own the property, get a boiler engineer to look at the boiler.

Check the meter

If we had just moved into a new home, we would make sure the lever that puts the gas on or off is set to ON because otherwise no gas would go through. We would also make sure the meter is not capped because many landlords now choose to cap the meter when a tenant moves out with the intention of uncapping it when a new tenant moves in.

If the meter is a credit meter, there will be no need to add any credit (money), but there should still be a display on the meter. If there isn’t a display, there may be a problem with the meter and we would contact the energy company.

If the meter is a prepayment meter, otherwise known as a pay as you go meter, we would check the balance on the meter and, if it has run out of credit, then we would top the meter up to ensure there was enough money for the gas.

If we did that and the boiler still didn’t go on, we would press the “reset” button on the boiler to reset it because if a meter runs out of credit and is later replenished with money, the boiler would need to be reset before it would work.

Check the radiators

If there is heat to some radiators and not to others, that indicates that there is a problem with the individual radiators only and not with the system as a whole.

We would check each radiator individually.

Air pockets

If the radiator is cold at the top with some heat at the bottom, that indicates a problem with air in the system for that radiator. This could be rectified by bleeding the radiator.

Sludge, debris or blockages

If the radiator is warm at the top and cold at the bottom, that indicates a problem with a build up of sludge in the radiator. This means that the radiator needs to be flushed, ideally by a professional, and we would book an engineer for this. If you have a landlord, you should contact the landlord about this.

Valve problem

Sometimes, the TRVs (Thermostatic Radiator Valves) get stuck. We would arrange for an engineer to fix this.


If we noticed any leaks coming from any radiator, this could be the problem and we would get professional help from an engineer.


We would follow a process of checking the boiler, then the meter, then the programmer, then the radiators, as above. In most cases, any issues would be resolved by doing that. If we were still confused and could not get the heating on, we would get professional assistance from an engineer.