vaillant turbomax pro combination boiler, the problem is that
when the hot tap is turned on there is hot water but only for the first 20 seconds, then it goes cold, when left running
the boiler seems to cut on and off, but the water temprature seems low to nothing, any help would be great!

nik, December 2008

Plate heat exchanger blocked due to the heating system not being cleaned out when the boiler installed

Tired Iron, December 2008