I was asked to have a look at a Vaillant ecoTEC plus 415, 15KW heat only boiler in Sheffield, that would reset but was failing to light displaying the F.28 fault code. They had no hot water and no central heating.
If you look the F.28 fault code up in the manual it gives this description and then goes on to list possible causes;
“Appliance does not start: Attempts to ignite during start failed”
The boiler was around 10 years old. Apparently it had not been looked at or “serviced” for around 7 years. The Vaillant ecoTEC Plus 400 range of boilers share the same design with the Glowworm hxi boilers and Vaillant ecoMAX Pro Heat-Only boilers. The heat exchanger is derived from the ecoMAX range of boiler that the ecoTEC range superseded.
Vaillant recommend you replace the Graphite burner door seals on their boilers every five years at minimum. The heat exchanger design on later models only use the single Graphite main seal but on the earlier models and models that use this “ecoMAX” heat exchanger they also have a small rubber seal at the bottom of the heat exchanger.
I have found that the rubber seal at the bottom has a life span and tends to start failing between 3-5 years depending on how much the boiler gets used. As such eventually it perishes and starts to leak. The main graphite seal doesn’t usually fail if installed properly.
So aside from the leak other issues you get with these models is that the insulation panels at the front and back can fail. In this boilers case it had been neglected for so long that the heat exchanger desperately needed cleaning. I suspect that this caused excess moisture to stick around longer than it usually would and caused the insulation pads to start failing.
Vaillant ecoTEC Plus heat exchanger after cleaning
You can see in the main photo that part of the insulation pad at the back had actually broken off and was contributing to the boiler failing to light. The burner on the boiler was being suffocated hence the F.28 fault code.
I can’t recommend highly enough that you get the burner door seal on Vaillant and Glowworm boiler that use this design changed at the recommended interval or sooner.
With this boiler I had to replace the rear insulation pad, front insulation pad, the burner door seals and the burner door itself which comes as a “flange kit”. The burner door head to be replaced unnecessarily as the screws which secure the burner to the door could not be removed. As such I could not replace the front insulation pad.
Vaillant ecoTEC Plus “flange kit” burner door
The flange kit does come with the burner door, burner door seals and the front insulation pad though.
I was able to get this boiler up and running with one visit. For whatever reason the boiler was only working at two thirds of its maximum capacity so I also reset the parameters to default settings which fixed the problem. Tested the boiler which was working much more efficiently.
Areas where I can repair your Vaillant ecotec plus heat-only boiler
I cover a large part of South Yorkshire including most of Sheffield, Rotherham and Barnsley. I also cover a small part of Doncaster.
Sheffield:
I cover most of Sheffield including central Sheffield, Chapeltown, Ecclesfield, Grenoside, High Green, Oughtibridge, Thurgoland, Wortley, Aston, Aughton, Swallownest, Todwick, Hillsborough and Stannington.
Rotherham:
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.
Barnsley:
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.
Doncaster:
I cover a small part of Doncaster including central Adwick, Conisborough, Edlington, Warmsworth and Mexborough.