Boiler cut out: problem with Boilermate III?

Hi. I have a Boilermate III (with LED display only - no digital as per manual), connected to a Potterton Suprima 30. A bizarre combination for a 2 bed house and hugely expensive to run. The Potterton has started cutting out before the Boilermate receives a full tank of hot water (usually about 6 green LEDs illuminated). It then will not re-ignite for at least 20 minutes, despite repeated attempts to manually reset it.

When it does work, the water coming out of the taps is if anything hotter than usual.

It could be the boiler, but I've had that checked and everything seems OK. Just wondering whether some temperature sensor might have failed in the Boilermate?

Any suggestions welcome, along with what to replace this system with which would be more economical.

Also, do you have the correct procedure for re-setting the Boilermate system please? It used to be on your site but I can't find it. The Gledhill manual only refers to the version with digital display.

Thanks,
Dan

Edit: just read the post from Steve. At least you have an electronic backup!

Hi Dan,

The Boilermate III matches itself to the boiler electronically. There is nothing for you to do as a user. (I expect you are thinking of the manual matching process needed on a Boilermate II)

Does your Suprima have the new(ish) Siemens control board? If so then this is probably the problem. A fault I've seen many times with these is that they run the boiler up to a different temp every time. Sometimes they turn it OFF at 70 degrees C, other times as low as 40 degrees C. This confuses the Boilermate III electronics totally! A new board in the Suprima (yet again) fixes it. Your current Seimens board in the Suprima carries a two year warranty if you want to get back to the people who fitted it...

Cheers, Mike

Thanks Mike. New temperature sensor and thermistor for boiler on order. Hopefully not PCB as it seems to be the original, which is about 10 years old. Fingers crossed the old Boilermate will keep going.