Potterton Suprima 120L playing up

Central heating boiler at church causing me grief. It has been OK through the really cold weather. In fact I left it on 24/7 as I thought the pipes might freeze.

Now it will run for an hr or so then stops. The green LED goes off and the red one flashes twice per second. I looked it up in the manual and that just says 'Lockout' You press the re set button and it comes on again.

This is a PITA because the timed settings should make the place warm before people start coming in but as it locks out after an hr, unless someone is there to re set it will remain cold.

Anyone got an idea? failing that a reputable gas heating eng in Blackpool that will come out this week for a reasonable fee?

Thanks

James

The MV must be open as the rads in the church and in the offices get hot. Pump must be running as rads getting hot? or would gravity feed keep them hot. I did turn the control on the boiler down to about 2/3 and it still locks out. Also turned room stat down.

will have a look at the pump and the header tank. If they are OK then I am not sure.

rev, I'll PM you a local plumber I use, he lives not too far from the church.

I checked the pump this aft and seemed to be running. All valves open too. It ran for 4 hrs until timer turned it off. No lockout this time.

Not sure what I've done but it seems OK. Looked on internet and many have had a PCB failure. (Refurbished ones available for