Hi, i have a 2 year old biasi condensing boiler, new wilo varispeed pump. radiators and circuit is old but ok. Since the system was installed it has always cut out, if the towel radiator is turned off, it cuts out around 4 times a day on either error 15/17/18. If I leave towel radiator on quite hot (waste of energy) allowing good post flow after boiler reaches temperature, runs for a couple of weeks at a time without cutting out. Board/heat exchanger/thermistor was changed by Biasi, thought to be blocked, but same problem, cuts out with error 17. I have to overheat my utility room with towel radiator on to keep system going. To be fair Biasi is trying hard to get over this. My frustration is, if I threw boiler away and fitted an old(inefficient)type boiler, it would actually be more efficient, due to lack of unwanted heat via towel rad. Any suggestions would be appreciated. regards Pete
ps. Room stat in lounge is left high so rest of house can be controlled on TRV's
How does it perform if you take a different TRV head off at the other end of the house instead - is the towel rad quite close to the boiler?
the towel rad is at the other end of the house,
it may be that when boiler reaches temp, the run on may not get rid of heat,
this upsets temperature readings, boiler cuts out
are you thinking it may be that when boiler reaches temp, the run on may not get rid of heat,
this upsets temperature readings, boiler cuts out?
Yes, what happens if you turn it off altogether but leave the rest on (make sure a TRV is off)?
do you mean
turn off towel rad
but leave all but one trv left in place except one(remove it so there is full flow through one rad)
Yes, let me know how the system copes over the next 12 hours or so
I have done this,
will let you know,
Boiler cut out, but the rad I took valve off, manual valve was only open 1/2 turn,
so maybe not enough flow.