Dodgy Potterton boiler?

Started this weekend, our boiler sometimes does not fire up on demand. The fan starts and continues to run correctly, and I can hear arcing/ sparking for up to 10 seconds from the vicinity of the PCB I think. Sometimes it lights, other times not. Last night it didn't want to work, but came on automtically this morning on the time switch. It's not overheating I don't think - I haven't had to press the red reset switch underneath, Nothing has been done recently to the boiler, it has been regularly serviced. I know all intermittant faults are hard to identify!! Potterton offered a 170 quid service to come out, identify and fix the problem, but if its a 2 quid part I would be gutted! (And xmas is coming!).
Can anyone identify the likely problem from my description, or suggest further simple tests I can do to narrow down the likely suspect component.
Thanks in advance for your help.
14:23 Tue 09th Nov 2004
 
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I'm not an expert by any means, but we have a potterton boiler which used to do the same thing, and our nice Gasman fixed it (twice!).

 

It doesn't sound like the same boiler as yours - our reset button is read and at the top, but this might help.

 

First, he changed the ignition lead, saying that the original ones weren't insulated properly and the spark often arced out before lighting the gas.

 

Then, he changed the PCB. Sorry can't remember why, but he said it was a common fault, andit did the trick.

 

Hope this helps!!

 

 

Its sounds like the same boiler as mine and i had the same problem. The problem is definitely your fan, mine sounded like it was working but (obviously) wasn't, i replaced the fan at a cost of �42 and its been perfect ever since.
Question Author

Thanks for the suggestions - first thing I'll try is the leads, presumably they are the cheapest and simplest thing to change!

Hattster: I can feel air being pushed out of the flue, so presumably that implies the fan is spinning - am I right in that assumptiom.

Thanks again.

Yes it feels like it is spinning and looks like it is....but it isn't! You can take the fan out if u want, take it to a heating contractor and ask him to test it for you, they usually do this for free.
There will be two silicone hoses coming from the fan assembly, check to make sure they are properly connected and not perished. If this does not solve the problem contact a CORGI registered heating engineer.
have someone check out the thermostat control they do wear out

you say the fan is working correctly and the ignition is sparking but not igniting the main burner, is the pilot light blocked?

Here are a few simple checks first,make sure the hot water&heating controls on your timer are set to continiuos turn on the room stat to on, any change?

turn on the control thermostat to 3 or above,any change?

Do you have a voltmeter,check and see if you have any voltage on test points T2-T3 no?replace electronic control, check also the 1amp fuse on the pcb,the electronic control is the box sitting on a pcb.

check and see if there is any voltage on T2-T4 no?check pressure switch by sucking on or blowing on the plastic tube that goes too the fan and listen and hear any clicking as the switch goes on and off  .

the other control is the gas valve which might have to be replaced,best left to a corgi fitter who will have to do a gas check

Is your boiler a suprima 30/40/50? My boiler is doing exactly the same thing as yours, In13b.

Am I right in guessing the PCB is the circuit board? If so I had this replaced by Potterton 2 years ago at the cost nearly �200!! Yes it did solve the problem but unfortunately I am having problems again.

Can't be the same thing again can it?

Can anyone help?! Thanks

moved house recently and had trouble with my boiler (suprima) after had one gas man out to fumble his way through to try and fix it. I spoke to next door and apparently the full street has had bother with the boilers PCB being at fault every time. i bought new pcb they apparently come modified with new wiring now, fitted it my self ( very easy for a keen diy person) and have had no more problems go for the circuit board ( pcb)  down side the new type card cost me �200 supply only

If your boiler is a suprima these are known for faulty PCB I know i have changed loads it is a very expensive part to replace advise to think about replaceing the boiler is the best option long term some good deals going on boilers replacement cost would be under a �1000.00 for a top make boiler GOOD LUCK.
Question Author

geebit, its a profile 50e. I am still convinced it is the pcb as I can watch small sparks underneath at solder points on it when the pilot is struggling to light. If the boiler doesn't fire, I have found that waggling wires attached to the PCB will generally cause it to light the pilot and all is OK for a day or 2.

A problem for me I think is that even if I source a replacement PCB, I will need a CORGI person to fit it as the ignition lead that comes off the PCB feeds through a rubber grommet into the main part of the boiler which is a front panel off job and something I assume I shoudn't touch.

Anyone out there care to confirm that front panel off = CORGI??

Thanks to all who have taken time to respond with advice.

 

In13b, well would you you belive it I too wriggle the wires/panel and it works for a short period, I thought I was the only one who knew this trick! Anyway as it is now getting ever more colder I called a British gas engineer out and after much deliberation he has said it is the definately the PCB, didn't ask if a CORGI reg needs to install the ignition lead or not. Got to get it done as it is now annoying me, will let you know the results when the task is complete.

Hi In13b, I have a Potterton Kingfisher cfl 50 boiler and I have absolutely the same problem. The flame comes on sometimes and not at others. Amazingly, if I remove the front cover, it starts working.  How did you get the problem fixed, and how much did it cost.

Thanks      

I have fixed my potterton Profile 60F by removing the PCB and re-soldering all the dodgy dry joints on the PCB. These boards are very badly made and the heat causes them to deteriorate. Dont do this unless you are good with a soldering iron and be really careful as the tracks arent stuck on the board very well and come off, especially on the older boards. My boiler has been running fine since doing this for 2 years +!
Oh yeah, AFAIK you can work on the electrical bits outside the main boiler chamber without a CORGI license. Once you open the main boiler chamber you are in to CORGI territory. These boilers are fitted with lots of electrical failsafes and the boilers air intake and gas/exhaust is via the flu. The CORGI engineers remit is to make sure the nasty gasses stay inside the chamber and go outside, not into your house!

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