Viessmann FF Fault Code

[cimes]

I have a Vitodens 100-W WB1C that's stopped working showing a FF fault code. I've tried resetting it which it does OK but as soon as heat or hot water is called the screen shows all it's symbols and then it appears to go through another reset. It does this a couple of times then shows up the FF error again?

Looking at the manual it seems like it might be a PCB error but was wondering if anyone had any other possible causes? Also looking at the various part suppliers it looks like that control unit is on back order, does anyone have any experience of having these repaired instead?

Many thanks,
Colin

 

[Peter Spikings]

Hi,

I have this exact problem, what was your resolution? Engineer wants to try replacing water temp sensor but that tests OK with a multimeter.

Thanks,

Peter

 

[Eugen Ursu]

Hi
Same FF code for my Viessmann Vitodens 100-w WB1B combi boiler.11 years old. Reseting didn't fix the issue more than couple hours. I checked everything, clean the heat exchanger, checked the gas valve.I checked the PCB voltages. Still working for couple days and back to FF code. Finally I replaced PCB and looks everything is back in business.
Looks like according with more users replacing the PCB is the solution. if something it'll change I will let you inform. Anyway for us, in N.America, the parts are very expensive comparing with the European market, from double and up.

Eugen