Firstly you should check the power supply by checking the fuse or main circuit breaker, this can be fixed by a simple reset.
You should also check that your electricity is still connected by testing other electrical items in the house. If none of them are working then there’s a problem with your electricity supply and you will need to call your supplier.
Another tip to get you boiler working is by checking that the emergency control valve is open. If it is not, then it must be re-opened to allow gas to flow.
Also check your gas stopcock and open it if necessary.
If it is open but no gas is flowing, then there is a problem with your gas supply and you will need to call your supplier.
It is also important to check all of the settings and controls on your boiler. If you have a timer, check that it is set correctly and that it comes on at the right time. If not, you may have a problem with the timer or power source.
You should also check that the thermostat is set correctly. Try increasing the temperature setting on the thermostat, as the boiler will only come on when the thermostat temperature is higher than that or the room.
The numerous safety devices within a boiler can sometimes be tripped, meaning that your boiler will need to be reset. On most boilers, this can be done by pressing the reset button, which is normally on the front of the boiler. Please note that you should not have to remove an access panel to locate the reset button. If you are unsure of where your reset button is, check in your manufacturer’s manual.
If your boiler is an older model with a pilot light then check if this is lit. If not, you can reignite it by following the manufacturer’s instructions.
If your boiler is a newer model without a pilot light, you may want to try pressing the deblocking button to reignite the burner. If the gas pressure is too low, the system cannot be started up again by pressing the deblocking button. Most boilers of this type will reignite automatically once the minimum pressure is restored.
Low pressure is very common with combi boilers and can cause your boiler to run at a lower capacity than normal. Check the pressure gauge, which should be at 1 bar when the boiler is cold. If the pressure is lower than this then many boilers won’t restart for safety reasons and the deblocking button will not work to reignite.
You can use the filling loop to top up the system with more water to correct the problem of low pressure. This can be done yourself if you have a flexible filling loop, or you may feel more comfortable having a professional do this for you.
In particularly cold weather, your boiler’s condensate pipe may freeze, which leads to a blockage, causing the boiler to shut down. Symptoms of a frozen condensate pipe include error codes or warning lights on your boiler’s display, which will be explained in your manual, or a bubbling or gurgling sound emanating from the condensate pipe or the boiler itself.
If the condensate pipe is frozen then it will need to be thawed, which should ideally be done by a professional.
It could be that you are experiencing a problem with your radiator valves and not the boiler at all, so try adjusting your radiator valves to see if you can get them to heat up. For a standard lockshield valve, you will need to remove the plastic cover and use the appropriate tool (available at DIY and hardware stores) to adjust the setting, whereas a thermostatic valve can just be turned to the desired setting.
If you aren’t seeing a change in temperature after adjusting the radiator valves, you could have a problem with the valves, which will require a professional to replace it.