Excuse me, that I ask in English.
I have the IVT C 7 (installed 2004). I have followed the operation of the pump this winter and noticed that the extra heat will not turn on at all. I tried to use the pump only to back up heater (Guide, paragraph 5.4) but the pump flashes a 3599-3600sec readings. Additional thermal fuse is not tripped. Anybody know, what could be a potential problem?
Otherwise, the device works well.
A local company that installed the pump has stopped .