Help & Advice


Modern boilers

What to do if your boiler has stopped working.

Most common faults.

Power (electricity).

Check if you have power to your boiler. Are the lights on? is the display showing?

(I have been called many times because people /children have accidentally switched the switch that powers the boiler).

Thermostat & Timer.

Is your thermostat turned up? Is your timer definately on?

Is the boiler thermostat (temperature setting) set high enough?
Are the batteries ok in your timer? Replacing them.
(I have been called many times because they are not turned on).

System Pressure.

Combination boilers & system boilers, is the pressure ok?

Is the pressure gauge at the correct setting? Does the display/gauge read ok?
(This is the most common fault that people call me about. On Vaillant boilers this is the F22 Fault. See below for more information).

If you top up your system and then a couple of days you have lost the pressure again, then you have a leak.

First check the small over flow pipe on the outside wall, normally just behind the boiler.
If its leaking you will need to call me.
If its dry then you may have a leak on your central heating system, this is normally from a radiator valve. Check all your valves for signs of leaking.

Fault Codes.

Check if your boiler is showing any fault code; if so look them up in your manual. If you have no manual try looking on-line.

Press the reset button. This may fix it but if the fault code keeps coming back, then you will need to call me.


Locate the reset button on the boiler and press it to reset the boiler. If your fault keeps coming back, this shows you have a fault and you will need to call me. Some boilers do not have a reset button, so turn off the mains electricity to the boiler, wait 20 seconds then turn it back on.

(This is very common and an easy fix. Like most computers, power off and power back on).


With any fault, the engineer needs as much information as possible. So before calling me, write down detailed notes of what is happening. What the boiler is doing, what noise does it make, at what times, when it started, how long has it been doing it, what sequence does the boiler get to. The more information I have the quicker I can get to the fault, which means a cheaper bill for you.

System Pressure.

All combination boilers, system boilers and some heat only boilers work with a pressurised system. As the pressure drops over the year the system will need topping up. This is done via the filling loop. This may be on the boiler or on the pipe work outside of the boiler. Either way there will be a filling loop.

Some systems lose very little pressure others will be more. Most modem boilers will stop working if the pressure gets too low.

Note! Do Not overfill your boiler; this will give you more problems.

Check out my YouTube Channel, there are help videos avalaible there. You can go to the channel by clicking here.