My Potterton Suprima HE 60 is approaching 10 years old. A few years ago it went badly wrong because the metal flue had corroded (known design flaw) and condensate had dripped down through the boiler.

That was all fixed but every now and again it stops working. The programmer is on, the thermostat is calling for heat, the motorised valves have opened but the boiler is dead - no burner, no LEDs lit. And then half an hour later it springs into life as if nothing has happened.

A couple of engineers have looked at it but say there's nothing they can do when it's working - they need to see it when it's dead, but they never arrive quickly enough to see that.

So I'm thinking it's time for drastic action - my options would seem to be new PCB or new boiler. Given the former is likely to be considerably cheaper, is it worth trying, or is there a danger the fault is not on the PCB and it will be a waste of time?

One last wrinkle - this morning the heating was off but when I checked the boiler was showing an "Ignition" fault. However, resetting cleared it and it appeared to fire up just fine...

I don't know what the community is going to make of all this but any advice is much appreciated!

  • Ironically, earlier this week it locked-out with an ignition fault. An engineer diagnosed a failed spark generator which led to a faulty pcb which led to a corroded sump drain pipe connector washer (I think that's what he said). Hopefully that was the root cause and a new washer/pcb/spark generator will see an end to the problems!
    – lane
    Commented Dec 14, 2018 at 8:19

3 Answers 3


I never worked on one of this type boiler, however, my experience with hot water boiler's is that the boiler usually lasts much longer than the PCB. Due to the price difference I would opt for the PCB. One note, any electronic PCB does not do well when exposed to water from any source. They may still work but are usually prone to problems like the ones you are experiencing.


I'm wondering if this is a temperature-related problem, where the trouble (wherever it is) happens when the boiler is hot, and fixes itself when the boiler cools.

The next time this fails, you might try hitting the PCB with some cooling spray and see if the problem immediately goes away. If it does, then the PCB is the problem, and replace that sucker.

  • Interesting suggestion - thanks.It generally seems to occur first thing when the outhouse the boiler is in is cold, so maybe the temperature differential between the cold bottom of the pcb and the warm top could be a factor? I wonder if warming the boiler room would help...
    – lane
    Commented Dec 7, 2018 at 13:37
  • 1
    If this is a thermal issue, then I wouldn't try to manage it; there's no way you could ensure it won't happen again, or get worse, or whatever. Alternatively, this also suggests that local cooling could also trigger the problem, which would be another way to finger the PCB as the culprit. Commented Dec 7, 2018 at 13:42

You may choose to clean the PCB if condensate has dripped onto it Even after water damage has evaporated, it leaves various salts and minerals on the circuit board, enough to affect operation.
Remove the PCB and place it on a folded towel. Use a 1-inch paint brush and isopropyl alcohol to lightly but thoroughly scrub both sides of the board. Don't let the iso enter the plastic relays. Use another towel to remove excess iso, then let it dry or blow clean air onto it. It's a standard repair for contaminated boards.

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