Another Potterton Suprima 60 fault?

[phillik]

I have a 4 year old Potterton Suprima 60 that has been going well till recently when It started intermittently locking out. This I have read is typically the PCB but got it serviced anyway. The boiler man said that the PCB was discoloured and may need replacing. I am very competent at PCB dry joint repairs but was just putting the job off till I had a few hours to spare. (or just in case I made it worse during the cold spell). But even before touching it, the boiler seems to now have decided to operate constantly regardless of the timer, with the green light flashing. I have even removed the wire off the SwL (Heating Demand) to the boiler and it still keeps going.

I have now removed and refitted the PCB having re-soldered many suspect joints and reseated the chips. It has not locked out yet, but it still keeps thinking the demand is on regardless of 240v present on SwL or not.

Is this another typical PCB fault?

 

[phillik]

Answering my own post! Desperate measures in order to save £150 on a new Potterton Suprima PCB. As detailed in my post I was having intermittent lockout problems, which developed into a permanent demand for heating. PHEW. I re-soldered any suspect joints but still no fix. With nothing to loose now I followed the SwL line via a few components ending up at a chip HEF40106BP. This would be used as the general switch for inputs and sensors. It only cost 51p so I replaced it and BINGO, sorted. I am now waiting to see if I have any more lock outs ( I will reply again if I do.) I suspect that this chip could be another reason for intermittent lock out or death by power surges.

Please be aware that changing chips is a skill requiring a fine pair of cutters, a decent soldering iron, a solder sucker, a steady hand, and good eyes. Using the fine cutters, cut the legs off at the chip and then remove the chip body leaving the legs. Remove the legs one at a time with the iron and then suck the holes clean from the under side. Carefully solder in the new IC the correct way round.

Do this at your own risk

I AM SO COOL!!!

 

[taydo]

make sure you are wearing a permanent earth strap round your wrist also






it helps kill you quicker when you touch the mains lol just joking!!!!!

 

[robh]

Hmm
maybe this is the fix our elusive friend geeza was trying to tell us about in another similar topic. A good tip. Thanks.

 

[breezer]

when changing a chip. it is better to solder in a socket first (for the chip that is)

 

[ChrisR]

That's a cmos chip, as implied by those who mention the earthing measures, which makes it easy to kill by static electricity. As the staying-on fault appeared after the work on the board, it has to be a possibility that the chip was bust while the resoldering was done.

 

[phillik]

The second fault appeared before I even touched the boiler and was not caused by me. It was this new fault that forced me to to have a go and fix it, otherwise I would have put up with the lockout until the warm weather. Research pointed me to this site which the problem of dry joints and was of great encouragement. It did not go away after resoldering the iffy joints, so this was my next best idea.

This is a CMOS chip and great care is needed to avoid zapping it when fitting. I use a wrist strap.

There will always be a dabate as to fit a socket or not. I think they always were a source of addition connection problems.

Meanwhile the intermittant joint problem on my Hitatchi TV is proving a pig to find

 

[Malabar]

I have a Suprima 30. There was a power cut the other day in the area and the boiler failed. Required replacing the PCB at a cost of €350. Some investigations showed it happened to a number of other residents with the same model. More investigations on the web showed a group of residents in Cambourn also had serious difficulty after power cuts and restoration. Seemd the power supplier re-supplied at below 220v. The Low Voltage Directive states the re-supply range should be between 195v and 245v. This is the range that potterton manufacture their PCB to.

Problem occured when the re-supply of power comes in way below these figures in some cases it was measured at 138V. This caused the pump relay switch to switch on and off far too fast and caused the relay switch to melt closed. SO the service engineer says the whole board needs replacing. I say whats wrond with it? he says it's busted and needs replacing.

Anyway, potterton have said the problem is the fault of the power supply company, which technically i suppose it is, and that they have manufactured their PCB within the required specifications. Which I suppose they have (but My TV or Radio dont ever stop working after a power cut). They have also said they have improved the tolerances of the PCB components to avoid this happening again or at least reduce the risk.

My question is: Can I replace this relay myself? Where do i get one? I have soldered some stuff before.

I want to fix the old board and test it so if the problem happens again I can put the old one back in again and re-fix the new one.

Thanks.

 

[breezer]

you can change the realy your self, providing you know the specifiations of the one you have.

do not go by looks, differnt coils have different impedances, and voltages and contct ratings and ...............

 

[Malabar]

Ok, cheers. There are a number of chips, resistors and capacitors on the board. What does a standard relay switch look like ? Maybe I can get a part code from it and find a new one.

Any idea if potterton give more detail on the PCB layout and part codes etc ?

Thanks.

 

[breezer]

not being funny but all these are standard relays, you may try asking "potty" for a new one

 

[Tezb]

______________________________
lynda, moderator

I think its safe to say it has been solved after 3 years look at the date