Another Suprima 50 lockout problem!

6 Jan 2004
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United Kingdom
Hello all.

I have a similar intermittent lockout problem as others have experienced in this forum.

Basically, sometimes the heating and water goes off, and the red LED on the boiler is flashing on an off. As soon as I hit reset it fires up perfectly, first time, everytime and stays on for a day or two (or longer) before locking out again.

I have had the PCB replaced with a new one (previous PCB had thermistors which had broken solder joints) but still the problem persists.

The problem used to be every few weeks but latterly it is every few days. I suspect the safety/overheat thermostat but the engineer says there isn't one, only the thermistors on the PCB itself?!!

Any ideas? As I said, new PCB in last two weeks, so unlikely to be that, and it always resets perfectly happy, first time. And the boiler can run for days quite happily before suddenly locking itself out again.

Many thanks.
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I also have a Suprima 50 with exactly the same fault you describe, only it can trip out within 10 minutes of being reset.

Unfortunately because it is so intermittent I have only witnessed it once, where I think the solenoid may not have energised, as I didn't hear a click, but it alwayts lights as soon as you press RESET.

Do you hear a click when it fails to light?

Does anyone know of a solenoid that only fires intermittently???
:oops: Sorry all
Just did the search on 'Suprima' and realised that my intermittent problems could well be explained by dry/cracked solder joints on the pcb.

I'll let you know what happens.

I had the PCB replaced since there was damaged soldered thermistors etc., but the problem still remains.

My boiler never fails to ignite upon reset, it fires up very happily each and every time.

I had hoped the PCB would sort it, but sadly not. I suspect the safety thermostat is faulty.

Another engineer visit (number 4!) this afternoon!
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:LOL: Success!
Most of the connector pins and half of the relay pins were cracked, re-flowed all of them and now its been working for week without tripping. Thanks for the info. saved me money and hassle.

I also informed Potterton that with this many failures it is a design/manufacturing fault, I'm waiting for their Customer Liaison dept to contact me.
Is it possible that the new PCB you've had fitted, has the same 'design problem'?? Just a thought.
I have the suprima 60L and that does have an overheat thermostat that will cause a lockout if it gets a bit too warm. You could try turning down the boiler stat, to reduce the overall running temperature, and see if it reduces/stops lockouts.
When I had grief with my Suprima, I fitted a strap on temp gauge to the flow pipe to monitor running temperature, this gave me an idea that the boiler was not overheating. My problem turned out to be caused by cracked solder joints on the PCB. In fact, one of the poor joints was on the overheat stat connector pins. That would only have to go open circuit for a second to cause lockout..
Good luck with yours.
did you get any joy with the potterton customer liason dept?
I have had lockout problems with 2 Potterton boilers, Potterton replaced the first one after 6 months because it locked out every few days from the date it was installed and they had replaced most parts to do with the ignition sequence including the PCB without solving the problem. The second boiler worked for 8 months before having the intermittent lockout problem again. Potterton engineers came and tightened a connection on the PCB and it worked fine for 12 months then the lockout problems started again. I contacted Potterton and asked if there was a design fault with the boiler as it seemed very strange for 2 boilers to have the same problem and their response was totally unhelpful. Even though it was the same problem they said after 12 months it would be a chargable visit at £150 per visit. I would be very interested to hear how thwy responded to you as it seems to be a widespread problem with the PCB in their boilers

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