Viessmann Boilers Guide

Hi,

I have a Viessmann Vitodens 100 boiler, which I bought two years ago. Yesterday I got fault F4 on it. When the fault F4 occurs, boiler makes a louder ignition as if the spark is not catching the gas properly initially, but then a fame does not stay on. It repeats constantly before locking out. I would like to share that that there is a signal electrode on it for flame rectification and sparking. Looking for expert advice

Thanks

Jonny

Hi Jonny, fault F4 on Viessmann Vitodens 100 indicates faulty burner. The possible reason behind it that flame signal is not present on the boiler. I would advise you to check the ionization electrode & leads. Apart from this, do measure the ionization current, check the gas combination valve, gas pressure, ignition module, ignition & condensate drain. After checking and verification, press reset.