Hi people, our Vaillant Ecotec Plus boiler is failing intermittently with no fault code, and looks like costing a fortune and an eternity to diagnose and fix. I'm hoping that someone here can point me in the right direction for diagnosis before I freeze.
Symptoms: heating fails, sometimes for days, sometimes for short periods. Either the boiler refuses to acknowledge that there is a demand for heating (ie. no little radiator symbol appears, and it gives code S.30) or it flashes up a radiator symbol very briefly, that disappears and then the system goes round a fairly quick cycle of pumping, pump over-run, and water pressure checks (S.2, S.7 and S.97). We don't ever see a fault code - or an ignition sequence when it's like this. We're pretty sure that the fault is close to the boiler because an external pump (for underfloor heating) turns on when there is demand so the relay must be working.
Hot water is via a cylinder system and is affected as well. I'm told it is wired oddly though.
Recent changes: the pump was replaced about 6 weeks ago after a seal failed and because it was making a racket. The rest of the system is about 6 years old. I'm uncomfortable that this new problem has emerged only a short time after the pump replacement.
We've considered all sorts of things it could be, but we're assuming that if the boiler claims not to see any demand, it isn't a problem with safety cut-outs, thermostats, etc. Is that correct?
Any pointers or stories of similar cases would be very much appreciated.
Thanks!
Symptoms: heating fails, sometimes for days, sometimes for short periods. Either the boiler refuses to acknowledge that there is a demand for heating (ie. no little radiator symbol appears, and it gives code S.30) or it flashes up a radiator symbol very briefly, that disappears and then the system goes round a fairly quick cycle of pumping, pump over-run, and water pressure checks (S.2, S.7 and S.97). We don't ever see a fault code - or an ignition sequence when it's like this. We're pretty sure that the fault is close to the boiler because an external pump (for underfloor heating) turns on when there is demand so the relay must be working.
Hot water is via a cylinder system and is affected as well. I'm told it is wired oddly though.
Recent changes: the pump was replaced about 6 weeks ago after a seal failed and because it was making a racket. The rest of the system is about 6 years old. I'm uncomfortable that this new problem has emerged only a short time after the pump replacement.
We've considered all sorts of things it could be, but we're assuming that if the boiler claims not to see any demand, it isn't a problem with safety cut-outs, thermostats, etc. Is that correct?
Any pointers or stories of similar cases would be very much appreciated.
Thanks!
