Ebized Posted July 28, 2011 Share Posted July 28, 2011 Item: Boiler - Potterton Prima F40 - approx 19 years old. Issue: Being lazy in firing up - fan is running - hear the noise as though it is going to fire up - then clicks and stops and restart the procedure after a few seconds. It will eventually catch after a varying number of clicks and all is well and usually, but will not always ignite first time once it has got going the first time. Sounds like: When you use a cigarette lighter and the flint is on the way out before it eventually sparks and the flame is lit. Checks carried out: I've had two registered engineers look at it. One had a Electronic control module with him that he swopped with the original - made no difference so he put the old one back. Scratched his head and said he would go away and do some research - and that's the last I have heard. Second engineer looked and scratched his head and said he would go away and do some research and yes, you guessed it....... Me googling: Came across this discussion which seems to have worked for many - capacitor change (loose change costs from Maplin) and/or dry joints. Not something I would undertake under any circumstances BTW. http://www.howtomendit.com/answers.php?id=26383 The first useful answer (bottom of the link) prompted all the positive answers: I had this problem, and spent a long time experimenting with various ideas, but the cycling on and off happened everytime that the boiler started up from cold. Sometimes it would cycle the fan on and off for 40 minutes before it finally started. I took the "black box" out and examined it. I clipped the tops off the relays and cleaned the contacts with paper: still the same. I then examined the underside of the PCB, and found several dry (ie badly soldered) joints. This didn't fix it. I then replaced all the electrolytic capacitors on the PCB, total cost £1.50, and Bingo!! it all worked fine. The electrolytic capacitors have a "+" marked on the board, and you must observe this. C4 and C7 were 22uF at 63v and C6 was 4.7 at 63v (but check on your board) The 63v is important don't get any lower voltage. Get high temperature (105deg) if you can, as they get hot, and that's what shortens their life. One of mine was oozing out at the bottom. You can buy capacitors at Maplins or CPC via the internet. This will probably fix most boiler control boards: the electrolytics will always be the first thing to fail on any bit of kit that gets hot. Next Step: Before trying a third engineer do you guys think the results in the link are credible and worth getting an Enginner to try first? I don't want him to think I was telling him how to suck eggs but given two registered engineers have so far not helped I hope it will be third time lucky, with a little prompt from one of you guys perhaps. Any suggestions for a fix as I do hope a new boiler is not required Quote Link to comment Share on other sites More sharing options...
garetgax Posted July 28, 2011 Share Posted July 28, 2011 personally Id get a british gas engineer out. there a fixed cost and when we had an issue they sorted it. Just my opinion though. Quote Link to comment Share on other sites More sharing options...
Ekona Posted July 28, 2011 Share Posted July 28, 2011 19 years old? Tbh I'd consider that good mileage and start looking for a replacement. However, how many PCBs does the boiler have? Sometimes there's more than one, although I suspect that any engineer worth his salt would've checked for this before giving up. It's almost always a PCB error and I've changed my one twice when it was having an issue with firing. Quote Link to comment Share on other sites More sharing options...
Neilp Posted July 28, 2011 Share Posted July 28, 2011 19 years old? Tbh I'd consider that good mileage and start looking for a replacement. However, how many PCBs does the boiler have? Sometimes there's more than one, although I suspect that any engineer worth his salt would've checked for this before giving up. It's almost always a PCB error and I've changed my one twice when it was having an issue with firing. +1. If it's not consistenly getting to ignition stage with fan cycling on and off id certainly be looking at a pcb. The fan proving switch, if faulty, would throw it to error. If the burner catches a flame and then shuts off your looking at an ionisation probe needing replaced but the fact it works sometimes is a funny one tbh. Is it going to lock out at all and having to be reset before attempting ignition again? Quote Link to comment Share on other sites More sharing options...
Leeroy Posted July 28, 2011 Share Posted July 28, 2011 personally Id get a british gas engineer out. there a fixed cost and when we had an issue they sorted it. Just my opinion though. Do not do this, it will bankrupt you unless you subscribe to a 'care scheme' with them. However, we used to have British Gas Homecare(?) which was a yearly scheme and they get you patched up if your boiler fails - the boilers were decrepit and this proved good value for us. It isn't what you want to hear but the boiler is old and probably pretty inefficient....hopefully you can patch it up for another couple of years though Quote Link to comment Share on other sites More sharing options...
Ebized Posted July 28, 2011 Author Share Posted July 28, 2011 If it's not consistenly getting to ignition stage with fan cycling on and off id certainly be looking at a pcb. The fan proving switch, if faulty, would throw it to error. If the burner catches a flame and then shuts off your looking at an ionisation probe needing replaced but the fact it works sometimes is a funny one tbh. Is it going to lock out at all and having to be reset before attempting ignition again? Having been told the Prima's are good boilers and will last ages, blah, blah,... I suppose the fact it has given trouble free service over the 19 years made me hopeful a fix was available. It has never locked out and hs always kicked into life - sometimes almost straight away but at other times it may be the 10th attempt before it catches and 'fires up'. But something is not right and of course I would rather get it sorted before winter arrives Quote Link to comment Share on other sites More sharing options...
garetgax Posted July 28, 2011 Share Posted July 28, 2011 leeroy I thought that but the call out fee includes parts and if they cant fix it they dont charge you so not that expensive an option tbh. Jumt my opinion but it worked for us. Quote Link to comment Share on other sites More sharing options...
350 Russ Posted July 28, 2011 Share Posted July 28, 2011 i would have said it was the pcb, most of the time its always the pcb that goes. given its age i would consider looking into getting a new one im afraid. Quote Link to comment Share on other sites More sharing options...
Ebized Posted December 10, 2011 Author Share Posted December 10, 2011 Result After several visits by 'plumbers' who only seemed to want to flog and install a new boiler found one who specializes in fixing boilers and yes a new pcb, (at trade prices) and clearing the air supply pipe has done the job and being a Gas Safe engineer he was quite confident the boiler would go on for years So he now has my business and quite likely the other 9 houses in my road that all have the same boilers of similar 19 year vintage as he clearly has some contacts for parts with the new pcb costing just £85. Much better than C£2k on a new boiler and bits and needless to say he got a good drink for his efforts on top of his very reasonable charge. Given the time of year the other 'alf is well pleased and got some extra brownie points Quote Link to comment Share on other sites More sharing options...
Neilp Posted December 10, 2011 Share Posted December 10, 2011 Result After several visits by 'plumbers' who only seemed to want to flog and install a new boiler found one who specializes in fixing boilers and yes a new pcb, (at trade prices) and clearing the air supply pipe has done the job and being a Gas Safe engineer he was quite confident the boiler would go on for years So he now has my business and quite likely the other 9 houses in my road that all have the same boilers of similar 19 year vintage as he clearly has some contacts for parts with the new pcb costing just £85. Much better than C£2k on a new boiler and bits and needless to say he got a good drink for his efforts on top of his very reasonable charge. Given the time of year the other 'alf is well pleased and got some extra brownie points i still have an old baxi back boiler about 30 years old and still going strong. Will wait until it fails before ripping it out as its behind the living room wall and is a nightmare to remove Took a while to get it solved but glad you got it finally Quote Link to comment Share on other sites More sharing options...
Grantmitchell Posted December 10, 2011 Share Posted December 10, 2011 Result After several visits by 'plumbers' who only seemed to want to flog and install a new boiler found one who specializes in fixing boilers and yes a new pcb, (at trade prices) and clearing the air supply pipe has done the job and being a Gas Safe engineer he was quite confident the boiler would go on for years So he now has my business and quite likely the other 9 houses in my road that all have the same boilers of similar 19 year vintage as he clearly has some contacts for parts with the new pcb costing just £85. Much better than C£2k on a new boiler and bits and needless to say he got a good drink for his efforts on top of his very reasonable charge. Given the time of year the other 'alf is well pleased and got some extra brownie points Result, I had something similar with my old Potterton, I found exactly the same site discussing replacing capacitors but didnt want to end up making it worse, so bought a replacement from ebay, swapped it out and it worked fine - cost me 30 quid. I then thought ok lets try changing the capacitors on the old board , which I duly did and put it back in the boiler and it worked 100% too So I now have a spare if required. As it happens it was easy to spot the capacitors were at fault on mine becuase they had actually mushroomed up - not the board in question but this pic shows what to look for , the lines in the top of the capacitor are there to allow the top to dome if a fault develops. This then gave me the confidence to replace the capacitors in my faulty Thomson SKY Box , another result Quote Link to comment Share on other sites More sharing options...
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