I have a Potterton Suprima boiler with a Megaflow unvented mains pressure water heater. The pump has been running continuously except for a couple of seconds every minute or two. At the beginning and end of the two seconds the boiler clicks. Usually the boiler's LED flashes slowly green, during the two seconds it's flickering red. Hot water and heating are both off at the controller. The boiler stat is max, the cylinder stat can be anywhere, it appears to make no difference. Judging by the clicks when I turn the cylinder stat, the water temp is 70 degrees.

Disconnecting the cylinder stat makes no difference.

I've just disconnected the pump, the boiler still clicks for the two seconds, and fires up occasionally.

I'd like to get the water temperature down and stop the pump running needlessly. The boiler is 6 years old, with no evidence of any previous repairs.

Help please.
Thanks

MartinB, August 2009

Yet another faulty PCB. These Potterton PCB are notoriously unreliable. I doubt that there is a single Potterton Suprima that has the original PCB still working!

However, help is at hand. It is a dead synch to replace. You can buy repaired PCBs with 12 months warranty listed on eBay for around £55. They come with full, simple, step-by-step instructions. A moron could do this job. It should not take you more than 15 minutes to change it.

Just remember to isolate the mains power first and when disconnection the plugs, be careful to pull the ignition cable by the plug and not by the lead.

Terry Farrell, December 2009

New upgraded PCB for Your Suprima Boiler C/W wiring loom, should get everything tickedy boo again

Job for a RGI though i'm afraid

www.elanar.co.uk, August 2009