Vokera Excel 80sp humming noise-pump or fan?
I have a Vokera Excel 80sp and it's making a loud low humming noise when it's used for heating and hot water.Is this likely to be the pump,or could it be the fan?Also, if it's the pump, I understand it's a Complete UPS 15-50 pump.I've seen the Grundfos UPS 15-50 pump available.Is this the same type of pump that I can use?
Mauro Nocivelli
August 2006