Hi, help please, BIASI M90F.24S approx 7 year old, fitted honeywell CM921 rf thermostat - wired correctley - sender works with receiver but boiler fires at will - thermostat is working with receiver but will not fire boiler, spoke to both BIASI & HONEYWELL for the last week, they can not help - each say the other must be faulty ?? Boiler is working/firing & heating rads as it should, just not when the stat tells it to, fires on & off when it wants to. please help.
honeywell CM921 + BIASI M90F 24S
- Thread starter hondainsitu
- Start date
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Both should have asked you to do some TESTS ! That could then prove WHICH is at fault.
First thing to do is to disconnect the RF stat. Then see if the boiler still fires up.
Second thing to do is to link the two connections where the stat goes to and see if that reliably makes the boiler stay on heating.
I am assuming that you have already set the boiler's timeclock to the "timer" and "on" settings? Have you?
Tony Glazier
First thing to do is to disconnect the RF stat. Then see if the boiler still fires up.
Second thing to do is to link the two connections where the stat goes to and see if that reliably makes the boiler stay on heating.
I am assuming that you have already set the boiler's timeclock to the "timer" and "on" settings? Have you?
Tony Glazier
hi Tony, yes with the rf stat removed & link in place boiler fires fine ?
boiler mounted in loft hence need for (preferably) rf thermostat, this is in my sons home but I have same honeywell rf unit with ideal boiler works perfect
boiler mounted in loft hence need for (preferably) rf thermostat, this is in my sons home but I have same honeywell rf unit with ideal boiler works perfect
hi tony, failed to mention BIASI said to disconect boiler time clock so as not to confuse boiler with 2 timers
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hi Tony, thanks for that - dosn`t surprise me, I get the feeling non of em seem too eager to help.
I will go round tomorrow - re-plug the time clock - re-check everything and put another post then.
Worth mentioning, had a salus RT500RF fitted prior BUT first one only had 2 boiler contacts NO + COM, salus sent an older type unit with 3 conections, when fitted to NC + COM controller worked (not when fitted to NO + COM) the only problem was that if the temperature was overiden with either up or down say 18 deg to 20 deg after a short while the thermostat re-set the temp. back to 23 deg. (default setting) so if they wanted to up it they had to re-programme the settings as there is no manual setting on the salus system ! they have baby twins and wanted to set the unit to on constant during the night - set it to 18 deg and forget it until the following day - but when at 2am they woke up sweating as it had re-set itself to 23 deg. not safe for babies, salus said unit could not be used in manual mode ! this is driving me nuts and been going on for about 2 weeks now. thanks for your help so far, will post again tomorrow in the hope it can be sorted out
I will go round tomorrow - re-plug the time clock - re-check everything and put another post then.
Worth mentioning, had a salus RT500RF fitted prior BUT first one only had 2 boiler contacts NO + COM, salus sent an older type unit with 3 conections, when fitted to NC + COM controller worked (not when fitted to NO + COM) the only problem was that if the temperature was overiden with either up or down say 18 deg to 20 deg after a short while the thermostat re-set the temp. back to 23 deg. (default setting) so if they wanted to up it they had to re-programme the settings as there is no manual setting on the salus system ! they have baby twins and wanted to set the unit to on constant during the night - set it to 18 deg and forget it until the following day - but when at 2am they woke up sweating as it had re-set itself to 23 deg. not safe for babies, salus said unit could not be used in manual mode ! this is driving me nuts and been going on for about 2 weeks now. thanks for your help so far, will post again tomorrow in the hope it can be sorted out
Hi Tony, did a few tests today with clock re-pluged, it looks like the PCB might be faulty - I have got a BIASI engineer coming tomorrow, he recons it might not be faulty after speaking to him by phone, cant get new board till Monday (its the older twin board - it appears the boiler is 2003 manufactured when purchased from B & Q ? new but 3 years old when purchased & fitted ? ) anyway, thanks Tony for your help this far if the weather had been not as cold I would have carried on but with baby twins just cant take the chance ! I will post final outcome when I find out for other members benefit - thanks will update soon.
The last four digits of Biasi serial numbers are the month and years of manufacture.
B&Q are not vey good at stock rotation.
Any normal engineer dealing with Biasi boilers would keep both PCBs in stock. Its most unlikely to be the PCB anyway!
Tony
B&Q are not vey good at stock rotation.
Any normal engineer dealing with Biasi boilers would keep both PCBs in stock. Its most unlikely to be the PCB anyway!
Tony
Hi Tony, engineer came today - we spent over an hour trying various tests - at first he said stat was faulty ! when stat removed & link in place boiler works perfect, remove link boiler continues to fire ? (presume it should stop) substituted known good thermistors - checked everything still working as it should, every whichway - finaly came to the conclusion it could only be the main board - is ordering board & I am waiting for his call to fit it probably Monday (fingers crossed) still not 100% this is the problem but does seem most likely.
the worst part about all this is in March last year I replaced my own Biasi 4 year old condensing boiler (again B & Q) for a new Ideal Logic Combi 30 (a deal I just could not afford to turn down at that time) and took a few parts of my Biasi as spares for my son (in the hope some will fit my sons) the boiler was working perfect ( I had just replaced the actuator & new stem which had leaked on the 3 way valve) I then took it to the tip !!!!!
I think the word doooooooh ! is the polite way to sum it up - I could have fitted it as a complete replacement in a couple of hours !! HINDSITE Grrr.
Anyway new board not fitted yet ! (please be the board ?) so I will post result hopefully Monday if fitted. Thanks again for your help (if it does not You will hear me cursing all over the country ) Thanks again.
the worst part about all this is in March last year I replaced my own Biasi 4 year old condensing boiler (again B & Q) for a new Ideal Logic Combi 30 (a deal I just could not afford to turn down at that time) and took a few parts of my Biasi as spares for my son (in the hope some will fit my sons) the boiler was working perfect ( I had just replaced the actuator & new stem which had leaked on the 3 way valve) I then took it to the tip !!!!!
I think the word doooooooh ! is the polite way to sum it up - I could have fitted it as a complete replacement in a couple of hours !! HINDSITE Grrr.
Anyway new board not fitted yet ! (please be the board ?) so I will post result hopefully Monday if fitted. Thanks again for your help (if it does not You will hear me cursing all over the country ) Thanks again.
Hi Tony, it turns out that the pcb was the problem all along - once the board was out you can see the burnt part (hidden under wires etc., when in situ) new board fitted everything now working fine.
Thanks again for your help very much appreciated, thanks again
Thanks again for your help very much appreciated, thanks again
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