Reverse Polarity blow PCB? Worcester boiler with overun

[UNG]

From the sound of this there could be a frost stat set too high or linked out if the system is running all the time

 

[Robinson]

Ok
The boiler requires a permanent live, neutral, cpc, switched live and a pump over-run.
inside the honeywell wiring centre you generally have a link between terminals 12 and 13 and another between 13 and 14
This is before you put any of your cables into the wiring centre. Did you remove these links and then just put one between 14 and 12?
If you have not then with your pump still running once the boiler has fired initially it will cause the boiler to carry on firing.
Hope i am making sense as i tend to waffle a bit

Not actually using one of the wiring centres i think.....just termination block in box 1-10...so boiler. honeywell programmer. honeywell termination box. honeywell room stat.

 

[Robinson]

what i meant is that i believe the wiring centre is not as you described.......your not waffling at all BTW....

 

[Robinson]

From the sound of this there could be a frost stat set too high or linked out if the system is running all the time

Gonna look into this tomo ..

 

[Robinson]

OK Guys got this diagram of mate for those who need. thought well useful for dim whit like me

 

[diditrain]

Hi Robinson, looked at your diagrams and they look right apart from the y plan one where there is a permanent live going to the mid position valve. Not usually required on the ones i have connected, but i have seen a one which required it.
Is it all new components that have been fitted in this installation?

 

[Robinson]

OK WELL we cracked it ! and it was a collection of faults some poss avoided .....1st ....this morn i buzz all cables out to see if the Rev Polarity i had was me ...turns out that wasnt MY connections it was some bright spark (HOW i dont know) had labeled the 3core stat cable to Con unit and 3core Programmer cable to con unit wrong way...the stat was the prog and the prog was the stat (if you get me) Then that sorted we get on only to find out that now not switching....called WOrcester
tech he said i must have LZ NZ connected and LZ straight to pump....... on ST10 i must also have LR LS link removed + Perm live and Neutral earth.....So sorted that still not having it......fiddled and fiddled again. realised we had the neutral from pump going to the neutral at con unit. NO GOOD it had to go straight back to NZ on pump overrun...then we finding out there a reverse polarity AGAIN this time at pump....But connected ok.....SO then remembered what NIKMET said in this post about 2 pin plug and what didi said about rev pol fault.....turns out YES the pin had been set wrong way around from manufature....i know for sure it werent us.....so sorted that all good.

Now back to the boiler just firing on and off constant when prog/cyll and room stat off....Call tech again he said double check you got no voltage at LR turns out i did have which was coming in from Conn unit.....And LS was causing it......Turns out i didnt need LS at all like 1st tech told me just LR going to valve orange and cyll stat HW on......took LS out from boiler and con unit and bam fine.......why on earth do they call the LR switch when it makes a lot more sense to call LS switch....

hope this made some sense.....BUT thanks guys for all your thoughts they all help alittle throughout the day to get this job done.....

 

[diditrain]

LS is live supply to your wiring centre for your external controls-timeclock/roomstat etc
LR is live return to your boiler
Manufacturers like you to take your feed to the boiler first

 

[Robinson]

LS is live supply to your wiring centre for your external controls-timeclock/roomstat etc
LR is live return to your boiler
Manufacturers like you to take your feed to the boiler first

arrrh Yeah i see......took me a around the houses way to learn....but i got there.....Its funnny cos i have not done for so long and i know its a bit edgying doing this
with not so much experience or lost experience...but i guess only way to learn....thanks for help.

 

[gas man]

lucky to get away with reversed polarity not killing the pcb,if it was a baxi new board time

 

[Robinson]

lucky to get away with reversed polarity not killing the pcb,if it was a baxi new board time

REALLY , gosh i did worry this would of happened..What actually happens to pcb if fried , i mean does it just not fire or could it just be certain functions not work...cos i mean it all seems to function a ok. but maybe there some elements to system i not aware of that been damaged...would hate to leave customer with a issue that should of been attended to now.....i not a bodge it a scarp per type guy... I break i pay .....

 

[Robinson]

Out of interest Are biasi same story....they nothing to do with baxi are they?

 

[gas man]

REALLY , gosh i did worry this would of happened..What actually happens to pcb if fried , i mean does it just not fire or could it just be certain functions not work...cos i mean it all seems to function a ok. but maybe there some elements to system i not aware of that been damaged...would hate to leave customer with a issue that should of been attended to now.....i not a bodge it a scarp per type guy... I break i pay .....

normally reversed polarity effects the detection /ionization circuits so it generally wont detect ignition and go to flame failure sounds like no damage has occurred to your pcb

 

[gas man]

Out of interest Are biasi same story....they nothing to do with baxi are they?

yes most boilers suffer the same way,and no biasi are not related to baxi most boilers will have a Honeywell, Siemens,thermowatt pcb honeywells prone to damage with reversed polarity Siemens not so honeywells can sometimes get a soaking,dry out and work,where as Siemens die instantly with the last brand thermowatt just looking at that one will cause it to burst into flames LOL most aristons have this make

 

[Robinson]

phew. !

 

[Robinson]

Yeah i had a job before which the building contractor tryed to stuff me, in fact has stuffed me for a whole load of dosh because he said i fried pcb...WHich is utter tosh. all i done was put a programmer and stat on...it was a combi biazi......But i know for a fact they has serious water leaks just by the boiler into the boiler...anyway the boiler worked fine straight of i done my job , but the Summer mode will not work and he said its because i fried it...the case is still on...i want full dianostic from biasi and fact it was a brand new boiler and he got a dodgey NON biasi engineer out to sort it(or not) is not my prop, tyring charge me for the call out fee of this bloke too....where it all should be under warrenty...

any thoughts

 

[gas man]

tell the building contractor to rotate he is not a gas engineer,water leaks are the likely cause of the pcb damage,tell him to prove you have damaged it(he cant they are very difficult to test)see if hes prepared for you to get a gas engineer mate take a look if he wont allow you to do this he is not letting you get all the facts so its your word against his,any way whats his problem if its in warranty?just get biasi out