Hi
I have a Viessman Vitodens 100-W combi boiler WB1B
If topped up to pressure 1 bar when turned off and cool, it goes down to about 0.4 bar after 1-2 hours. when it runs, it can properly heat up the radiators and provide hot water but the pressure keeps raising and rising and can sometimes go all the way to 3.5 bars.
there are not fault messages at all.
then when left to cool it goes back to very low pressures below 1 bar.
a serviceman checked the expansion vessel pressure and it was topped up to 1.5 bar - there where barely any water inside.
what could be wrong with this boiler?? please help
I have a Viessman Vitodens 100-W combi boiler WB1B
If topped up to pressure 1 bar when turned off and cool, it goes down to about 0.4 bar after 1-2 hours. when it runs, it can properly heat up the radiators and provide hot water but the pressure keeps raising and rising and can sometimes go all the way to 3.5 bars.
there are not fault messages at all.
then when left to cool it goes back to very low pressures below 1 bar.
a serviceman checked the expansion vessel pressure and it was topped up to 1.5 bar - there where barely any water inside.
what could be wrong with this boiler?? please help