Potterton Suprima 30L - Green Flashing LED

8 Jan 2009
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United Kingdom
I have a Potterton Suprima 30L with a Gledhill Boilermate 2000 thermal store. The system has been running beautifully for the past 2 1/2 years since the PCB on the Suprima was changed for the new version (5111603).

However, in the past few days, the boiler has started becoming 'stuck' with the LED flashing green, even though the required temperature has not been reached. It may stay in this status for hours, with the house becoming colder and colder. The problem is intermittent, and seems to occur when the temperature of the system is below 60 degrees (the magic number the thermal store needs to reach before it starts pumping hot water to the radiators. Hot water is unaffected.

Has anyone had any previous reports of this problem?
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most likely the pcb again. the last versions of the pcb have this fault.
If the HW is working fine, then I cannot see how it will be the boiler :confused:

I would want to check out the BM 2000, as this controls everything on your ch.

The boiler is just told to fire by the BM.

Isn't the flashing green light pump over run? Pump is not connected to the boiler when using a BM, though.
Thanks for the replies, I really appreciate your time and collective expertise. This problem is certainly making me scratch my head.

The hot water is not heated directly by the boiler. Mains water is passed through a plate heat exchanger in the Boilermate 2000 before being fed to the taps so just uses whatever temperature is there (I think this is fixed at 55 degrees).

We (me, my local heating engineer and Gledhill Technical Support Helpline) could not find any fault with the Boilermate, so are thinking the problem may lie with the boiler, although it is also not showing any obvious fault signs (red flashing leds, strange noises etc.)

Have been searching forums for the past 2 days trying to find if anyone else has reported same problems - there has got to be plenty of identical systems out there?
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Oh, and the green flashing LED on the boiler means 'Boiler Temperature Control Satisfied' according to the manual.
I am rapidly coming to the conclusion that the boiler PCB is at fault, especially as I have managed to get the CH going this evening by switching off power to the boiler and switching it back on again a few times. Eventually boiler kicked in, green LED stayed on and my rads are warm.

So need to buy a new 5111603 from somewhere...... great.
In that case I bow to nickso's experience, as I have not come across this pcb fault as yet.

nickso, is this the new pcb assembly's that are faulting or the original pcb's :?:

had this a quite a few times.

the boiler thinks its up to temp no matter what the demand is. everyone changes the thermistor thinking its a temp problem. they are right it is a temp prob but its the pcb reading the temp wrong not the t/m.

this is the only fault i know on the version 3 pcb's. its extremely rare and i know of no other issues with the v3 pcb.
You do not need to change the whole kit.
The PCB can be replaced separately Prt no. 5112178.
nickso.. are you saying theat the newest sup. board has started to go duff. the one with the wiring harness and new earth and ign leads in the box?
yes they have this particular fault but its not common. ive maybe only had to change a few for it.
I'm glad the diagnosis appears to be correct, but I have already ordered 5111603. Luckily there isn't a huge difference in price between that and 5112178 (£10).

Thanks for all your help. This site is a great resource of information.

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