Hi there,
Being not trained at all in boilers, gas or plumbing I generally don't mess when we have issues but this problem seems pretty unusual so before I inve st in a fix I thought I'd seek views.
Last Sunday morning the heating didn't fire up so I went to clear the error , expecting it to be low pressure or something. The error wouldn't reset (c an't remember the code) so I went to scroll through the menus and the displ ay froze. None of the buttons would work, boiler wasn't I firing up so took the main power fuse out and left it for 5 minutes. When putting the power back on the fan fired up for a few minutes and then stopped. Display stil l frozen showing current system temperature. 10 mins later Error 01 came up but buttons still not responding. Boiler wouldn't respond to a demand. Se rvice reset button did nothing.
So with much protestation from the wife I took out the main and display pcb s and gave them a hoover and checked for any blown capacitors or burnt out resistors. Nothing visible wrong with the boards. Put them back in, turne d the power back on and still nothing. Display still showing current tempe rature with no other symbols and buttons not responding. Then, with demand coming from both the heating and hot water, I pressed the service reset ag ain....
And the boiler immediately fired up! Went through start up cycle then rampe d up to 100% and stayed there. Display still showing same temperature with no burner or fan symbols showing and buttons not responding. The whole hea ting system got up to temperature and pump working. With no readout and bo iler running at 100% I was nervous to say the least but it did turn off whe n I removed the demands on it. Next time I left it on longer and kept chec king inlet and outlet water pipe temperatures. When the inlet got too hot to touch I thought it was time to cut it off again but by this time the rad iators were boiling, way hotter than the setting we had previously. So it seems either water temp setting isn't working or there's no feedback from t he temperature sensors.
We're fine with the immersion and oil filled rads at the moment, so not in a particular hurry. To me it seems like a PCB issue and probably the displa y PCB, since the buttons aren't responding and the water temperature settin g isn't working, but a main board issue could possibly cause the control pa nel to act like this too.
Sorry for the long description but if anyone has any thoughts to help diagn ose the problem or has had similar problem I'd be pleased to hear from you.
Many thanks, Phil