Had a Vitodens installed in 2012. Call outs to change blocked filters, this despite having a Magna clean fitted. Pressure loss constantly. Rad's take a while to warm up (water is fine). 21/09 both Rad's & water stop heating. Rang Viessman with error code on 22/09. Nobody will call out on weekend and will contact me Monday. Did not contact. Rang again to be advised I'm out of warranty (fair enough) so not a priority and they will contact me sometime later in the week. £225 + VAT call out. Today 03/10 I get a call to arrange a call out sometime later this week. Excellent customer service NOT. Needless to say a minimum of 12days without hot water/heating is unacceptable. Had a Baxi fitted last week with 10yr parts & labour warranty fitted. If you have to wait 12days for them to deal with warranty calls that says it all about their boilers. Do not touch with a bargepole