Potterton Suprima 30 Relay Clicking

[mehstg]

Hi all

I have a Potterton Suprima 30 boiler that has stopped working over the last couple of days. The issue is intermittent and sometimes it functions correctly.

Some times, when heat/hot water is demanded, the boiler fails to start. When this happens, the fan does not start and I can hear a relay clicking on/off repeatedly. I can also hear the grundfos pump in the airing cupboard spinning up/stopping, this correlates with the clicking of the relay. I uploaded a video to show this (http://www.youtube.com/watch?v=SRakdvfmpFI). I have also taken the screw off the front of the pump and ensured that it is spinning freely.

Fearing PCB issues, I have popped the board out to inspect, and cannot see any dry joints under a magnifying glass. I have experience with microelectronics so am more than happy to resolder components if this is the issue, however at first inspection, the board looks OK.

The boiler has the Siemens LMU30.211B159 board, judging by the hand written label on the faceplate, i'd imagine this has been replaced at some point in the past.

Any ideas where to begin fault finding. More than happy to call in a Gas Safe engineer after the bank holiday weekend, unfortunately everyone I have called so far seems to say 'dump it mate, replace with a combi' and has no interest in fixing it. For the record, I have not, and will not open the combustion chamber side of the boiler.

 

[hertsboilers]

Most of boiler repair engineers are only able to diagnose to board level not component level.

Get a new board then.

 

[Agile]

There is a redesigned and more reliable PCB for your boiler.

More expensive too.

The fault is caused by drilled holes which are too large to hold the plug socket pins firmly so all the stress goes into the solder joint.

If you much repair it then resolder all the socket pins along the edges of the PCB and you will probably have found what was wrong.

But it could also be a relay with burnt contacts too!

Tony

 

[mehstg]

What is the latest board with the improvements then? Is the Siemens not it?

Just to update. I took the PCB out today and re flowed/resoldered everything I could get to to with no avail. The issue persists.

 

[steve32]

Have you checked the switched live supply to rule out external faults

 

[Agile]

Sorry the symptoms you described were typical of the old PCB and when you said you had "popper out" the PCB that is a better description of how the old type was removed.

The new type is in a plastic box and is much more reliable. When they do fail it is usually not working and gives a fault code. The only two I have seen have both given a code for a low mains voltage.

It might not be the PCB in your case but one of the possible causes involve a component which monitors the combustion and come within the range of faults which we don't give DIY advice on.

So you could replace any relays you think are possibly at fault, but a new PCB or call an engineer.

You could also measure the voltages applied to the PCB and see if they are all what you would expect to find.

Tony

 

[hertsboilers]

Tony are we talking about Suprima, fault code?

 

[Agile]

Yes, Ming, they have about five different fault codes including the low mains voltage which is what both of the faulty ones I have visited have shown.

Tony

 

[Steelmasons]

Fault lights not actual codes.

 

[Agile]

I would call them codes as they are similar to morse code with series of flashes etc!

But not alpha numeric codes!

 

[mehstg]

Thanks for the help guys. I'll get an engineer round before going any further. Your description of the board is exactly as mine. It's encased in a grey box but came out easy enough.