Please use your browsers search function if your boiler has a fault to see if it is one of the more common faults listed on this page
The advice is broken down into the following:
- What type of boiler do you have
- General advise & top tips
- Boiler faults & what you can do to get your boiler working
We are not responsible for any outcomes following our advise, we recommend consulting the manufacturars instructions before acting on any advise, and wherever you do not feel competent, we recommend a Safeheat Homecover engineer’s visit.
What Type of boiler do you have?
A combination boiler
This type of boiler will provide hot water on demand. It will require pressure to function correctly, and nearly everything to make the installation work will be inside the boiler itself. It normally has no external water tanks in the loft or high up space, or a hot water cylinder.
A conventional boiler
This type of boiler is normally not pressurised. It requires a separate hot water cylinder, and storage tanks that are normally in a loft or at a high level. Pumps and diverter/zone valves are external to the boiler.
A system boiler
This type of boiler is pressurised and has an internal circulation pump (like a combination boiler), however, it also has an external hot water cylinder like a Conventional boiler. It can sometimes, but not always, have 1 storage tank in the loft.
General Advise & top tips
- Always test your heating every 2-3 months even throughout summer – This will help prevent diverter valves and lone valves from seizing after being in the ‘hot water position for too long.
- Only bleed your radiators if they are cold at the top, and only if you know how to re-pressurise your system if it is required.
- Turning your room thermostat up higher will not make your home heat faster – a thermostat is an on/off switch, so long as it is set higher than the room temperature, it should come on.
- A TRV or thermostatic radiator valve does not control how hot the radiator gets. The valve senses the temperature of the room that it is in, and only once the room gets to the set temperature, will it self-close to turn the radiator off. Note – Setting 3, is normally a room temp of 19°-21°
- ‘Smoke’ from a modern condensing boiler’s flue is actually water vapour and is completely normal.
- A condensing boiler will produce condensation which will drain away from the boiler via a plastic pipe. It can run to an external drain, or internally to a waste pipe such as under a sink.
- Always take the time to get a basic understanding of your system, such as how to isolate your gas supply in an emergency, whether your controls require batteries, and how to top up your system pressure, BEFORE you need to.
Boiler faults
Boiler is not responding to a request for heating
Cause
This is when you have turned your heating on via your timer or programmer, and turned your room thermostat to max and the boiler still isn’t coming on. This can happen on any of the types of boilers.
What to do?
This is likely a fault with your programmer or room thermostat. If they use batteries, ensure that new batteries have been fitted, set the heating to off on both the programmer/timer and the thermostat, and then turn it back on as usual.
If your boiler does not come on after this, it could be a wireless connection issue, or where it is not a combination boiler, a motorized valve which would require a Safeheat Homecover engineer’s visit.
Hot water usage/demand is causing the heating to warm
Cause
This can happen on any of the boiler types but noticed in different ways.
On a combination boiler – running a hot tap such as a bath will heat the radiators and can cause the hot tap’s water temperature to be lower than normal or even cold.
On a system or conventional boiler – When your hot water comes on at its programmed times, the radiators will heat at the same time.
Note that the reverse of this can happen where the hot water can be heated when the heating is set to be on. Noticeable by having unusually cool radiators/circulation of heat.
What to do?
This is a fault with an external motorised valve or an internal diverter valve if it is a combination boiler. This fault requires a Safeheat Homecover engineer’s visit.
Low Pressure
Cause
Low pressure can only happen on pressurised system such as a Combination, or system boiler (some conventional boilers can be pressurised too but this is fairly uncommon). This fault can show if a radiator has been bled, there is a leak on the system, or from time to time when the boiler vents air itself.
Different boiler manufacturers use different Fault codes to advise of the fault, below are some of the low pressure codes, but these are not complete and may vary from model to model:
Glowworm / Vaillant / Heatline – F22 – or flashing 0.0 – 0.5
Baxi / Potterton – E118 or E119 (it will display 2 digits at a time)
or flashing led 60°
Ideal – F1
Please note that many new boilers will have a digital display that will directly advise of “low pressure”.
What to do?
If you know the cause of the low pressure, such as work on the system, of bleeding a radiator, you can re-pressurise the boiler/system. The pressure should be raised to between 1bar, and 1.5bar.
If there is no known cause of the pressure loss, you should check for leaks under the boiler, on all radiators, all valves, and any accessible heating pipework. If you cannot find any leaks, you can raise the pressure to between 1bar, and 1.5bar.
If you do fine a leak, you will need to call a Safeheat Homecover engineer to complete a repair if you are not competant to do so yourself before raising the pressure again.
To raise the pressure, sometimes you can use the boiler’s own fill valve if it has one, or an external system filling loop (a silver braided hose connected to two pipes) that is normally located underneath the boiler or sometimes by the hot water cylinder. A filling loop will usually have two valve either end of the braided hose, opening one should allow water through to the next, and opening the second will allow the water to flow into the system and it will begin to fill. By opening the valve slowly means you have control over how fast it fills and you can turn both valves back off once it hits between 1bar, and 1,5bar.
Note – if you raise the pressure much over 2bar, you may need to bleed some water out of a radiator’s air vent into a container to bring the pressure back down.
Ignition Fault
Cause
An ignition fault can happen on any of the types of boilers. Boilers made after the early 2000s will no longer have a permanent pilot light, instead they will fire up when they need to. They will need to light the flame each time they need to heat water for heating or hot tap water. With this more frequent ignition, boilers sometimes fail to light, or cannot successfully detect that the ignition process was successful.
Glowworm / Vaillant / Heatline – F1, F4 or F16
Baxi / Potterton – E133 or E128 (it will display 2 digits at a time)
or Flashing 30° LED
Ideal – L2 or F2
Please note that many new boilers will have a digital display that will directly advise of an “ignition failure”.
What to do?
If it is winter, and outside temperatures are near freezing, a frozen condense pipe outside could cause a blockage causingt he condense to back up. If you suspect this has happened, you will need to defrost the pipe. Pouring warm (not boiling) water over the length of the pipe numerous times can clear this and then resetting the boiler should clear the fault.
If your boiler shows an ignition fault and it is not a frozen condense, firstly try to reset your boiler. It may just need a second attempt.
If the fault returns, check any other gas appliances are working. If you have no other gas appliances or if they are not lighting too, check that your gas meter is not showing ‘OFF’ or that it isn’t out of credit if it is a pre-payment meter. There is an emergency gas supply shut off valve near your gas meter, ensure that this is on and in line with the pipe. If other gas appliances are working or all other checks are ok, ensure that the gas supply under the boiler hasn’t been accidentally turned off (this can happen when attempting to raise the pressure). After completing these checks and any problems found and turned back on, reset the boiler and try again.
If the fault continues, the fault will require a Safeheat Homecover engineer’s visit.
Fan faults
Cause
A Fan fault can happen on any of the types of boilers. When a boiler has a Fan fault, it will not allow the boiler to light as a safety precaution. The following codes are fan faults:
Glowworm / Vaillant / Heatline – F2 or F3
Baxi / Potterton – E160 (it will display 2 digits at a time) or Flashing 50° LED
Ideal – L2 or F2
Please note that many new boilers will have a digital display that will directly advise of a “Fan Fault”.
What to do?
If your boiler shows a fan fault, firstly try to reset your boiler. It may just need a second attempt.
If the boiler begins working, it may be an indication that a component is failing and the fault may return in the future. However, if the fault continues, the fault will require a Safeheat Homecover engineer’s visit.
Pump, circulation and overheat faults
Cause
A Pump fault will only happen on a combination or system boiler.
A circulation or overheat fault can happen on any of the types of boiler.
A Pump, circulation or overheat fault is when a boiler doesn’t detect when a pump is running, when a pump is not running properly, or something in the system is causing an obstruction. There is a wide range of fault codes that are a vague result of these faults:
Glowworm / Vaillant / Heatline – F5, F14, F25 or F26
Baxi / Potterton – E125 or E110 (it will display 2 digits at a time) or Flashing 40° LED
Ideal – L1
Please note that many new boilers will have a digital display that will directly advise of a “Pump Fault”, “circulation fault” or “overheat fault”.
What to do?
Pump, circulation and overheat faults can be caused my many varied issues. The most common is a failed or weak pump which would require an engineer, however low pressure, air in the boiler, sludge in the system and too many radiator valves being closed can cause these faults.
Firstly, check and raise the system’s water pressure if needed to between 1bar and1.5bar or check that the system hasn’t ran dry of water (this can be done by bleeding the highest radiator until water comes out.
Secondly, ensure that all of the radiator valves are not closed or set too low, the boiler will continue to try to pump hot water around even though the radiators are off.
If the pump is at fault, or the system/boiler is blocked with air or sludge, the fault will require a Safeheat Homecover engineer’s visit.