gazthepottertonengineer said:
nickso said:
not being funny but did potterton ever give a good reason for not having a service history or installed correctly being a contributory factor to a high pcb failure rate?
serious question with absolutely no sarcasm at all. just want to know what possible difference they think it could have made.
dont think there was any specific statemant but if the boiler is in a cupbard without ventilation then the obviously the pcb will get too hot and fry circuits
inadequate ventilation is a possible cause yet i have changed a high number of pcb's on suprimas in and out of cupboards. no other manufacturer seems to have similar problems that i can think of that would readily be attributed to ventilation.
and also alot of the jobs i goto are locking on overheat normally due to pump not wired back to boiler or no bypass
but you are not saying that this causes the pcb to go faulty. you are saying that these are misdiagnosed as a faulty pcb, yes?
and its important to service the boiler to check gas pressures spark electrode gap etc to reduce the chances of nuisance lockouts
ive seen hundreds of them and only found one faulty electrode and a few at the wrong setting. certainly worth checking though.
i bet that not all 3 of those new pcbs were actually needed at all but like all of us we get blinded and go in with our blinkers on and say "oh must be the pcb"
and yet in the majority of my cases it has indeed been the pcb at fault. and ive had several that have had 3+ pcb's. not all for the same fault i will admit in some cases.
baxpoti said:
0.1% What is a low failure rate?
where did you come across this figure? surely not from the above post by simond which we cant really rely on as it is purely based on the watchdog figures, which the OP has already pointed out cant be correct as they are based on the amount of people who phoned that programme ,not the amount of actual breakdowns. it would be impossible to guess the actual figure but i think we can safely assume it is far higher than that.
In MY opinion the failure is caused by overheating... caused by.... not being installed to M.I. e.g. no cooling ventilation, no pump overrun, no by-pass, undersized flow and returns (35mm req'd on the 120) etc etc.
so in your opinion does the pcb not being wired correctly, or no bypass, or undersized flow and returns, or a combination of all the above, directly cause the failure of the pcb? poor ventilation i can accept, but with the rest i cant see any correlation. are you also saying they have been misdiagnosed or are you saying that the overheating of the boiler subsequently overheats the pcb? in that case surely the boiler casing is inadequately insulated against overheat. another part of poor design possibly?
I went to one of the Barratt sites featured on Watchdog, approx 50-60 houses. 2 Pcbs have been replaced on that site following the programme and that includes the family interviewed.
i personally must have replaced close on 150 in my area in housing estates that also all have suprimas. many houses have had repeat visits for the same problem. to my knowledge i have misdiagosed twice. one was the gas valve and the other was an intermittant thermistor.
for all your arguments which may or may not be correct the suprima does indeed have an issue with the pcb. other models/manufacturers do not, even though they may suffer from the same potentially poor installations in some cases.
incidentally the latest pcb is very reliable i think. the only problem i tend to have with it is the pcb believing its up to temp when its not. its quite a rare fault though.