Vaillant ecotec F28 fault code

vaillant f28 fault code explained and how to fix

The Vaillant F28 fault code means the appliance burner has failed to light or the printed circuit board has failed to detect the flame.

If you look in the Vaillant installation manual in relation to the F.28 fault it states the following;

“Failure during start-up: ignition unsuccessful – Gas meter defective or gas pressure regulator has triggered, air in gas, gas flow pressure too low, thermal isolator device (TAE) has triggered, condensate duct blocked, incorrect gas restrictor, incorrect ET gas valve, fault on the gas valve, multiple plug on PCB incorrectly plugged in, break in cable harness, ignition system (ignition transformer, ignition cable, ignition plug, ignition electrode) defective, ionisation current interrupted (cable, electrode), incorrect earthing of boiler, electronics defective”

Even if you don’t know anything about fixing boilers, if you read the description above then you should be able to tell that there are quite a few possible causes of this problem. A few of the common ones include; no gas, a problem with the gas supply or even a blocked or frozen condensate pipe.

In my experience I have found that on the first generation ecoTEC models manufactured from 2005 – 2012, sometimes the printed circuit board fails and can cause this problem. This happens when the circuit board doesn’t recognise the flame for whatever reason. Gas valve failure is not a common on these early models.

Vaillant ecotec F.28 fault

vaillant f28

However quite a common problem on the second generation ecoTEC manufactured from 2012 onwards, is that the gas valve often fails. I have replaced gas valves on both the PLUS and PRO models. This fault usually starts off as an intermittent problem which can be reset and usually fails completely at some point.

As a homeowner all one can do is try the reset button, test other gas appliances and check if the condensate pipe is frozen, which may happen in cold weather if the pipe runs externally.

Printed circuit board’s and gas valves that have failed, or are in the process of failing are non serviceable items and need to be replaced by someone who is Gas Safe registered, competent and confident enough to work on these Vaillant boilers.

If your Vaillant boiler is displaying the F28 fault code and you live in my locality and would like me to have a look at this for you then please get in touch. I am sure I can help.

Richard contact numberemail address

Areas where I can repair your Vaillant ecotec F.28 fault

areas that are covered

I am located in Elsecar, Barnsley, South Yorkshire. I cover a large part of South Yorkshire including most of Sheffield, Rotherham and Barnsley. I also cover a small part of Doncaster.


I cover most of Sheffield including central Sheffield, Chapeltown, Ecclesfield, Grenoside, High Green, Oughtibridge, Thurgoland, Wortley, Aston, Aughton, Swallownest, Todwick, Hillsborough and Stannington.


I cover the whole area of Rotherham including central Rotherham, Brinsworth, Catcliffe, Canklow, Masbrough, Treeton, Whiston, Greasbrough, Kimberworth, Thorpe Hesley, Rawmarsh, Wentworth, Bolton-on-Dearne, Goldthorpe, Thurnscoe, Wath-on-Dearne, Mexborough, Swinton, Kilnhurst, Hooton Roberts, Ravenfield, Thrybergh, Bramley, Hellaby, Maltby, Thurcroft, Wickersley and Braithwell.


I cover most of Barnsley including central Barnsley, Birdwell, Stairfoot, Worsborough, Kendray, Ardsley, Athersley, Monk Bretton, Lundwood, Royston, Brierley, Cudworth, Cortonwood, Great Houghton, Shafton, South Hiendley, Brampton, Darfield, Wombwell, Hemingfield, Elsecar, Hoyland, Jump, Barugh Green, Cawthorne, Darton, Dodworth, Gawber, Mapplewell, Pogmoor, Staincross, Wilthorpe, Worsbrough, Thurnscoe and Tankersley.


I cover a small part of Doncaster including central Adwick, Conisborough, Edlington, Warmsworth and Mexborough.