Help. My M90F 28s has packed in. Flashing red light. When i press reset the red light goes out and the boiler whirs away ten seconds and then stops again with red light. No hot water neither. How do I put the boiler into diagnostic mode.
I hope I am not just paying to show me how to do a diagnostic?
I am hoping we can find the problem.
Boiler has been working intermittently. What I have discovered is that when i press the reset button, while the boiler is whirring away, if I turn on the hot water tap, the boiler will fire, and keep running hours before locking out again. If I don't turn on the hot tap, the boiler just whirrs away to fifteen seconds, then locks out again.
Yes the pump is definitely running. I think it may be cutting out on high limit. My wife has been turning down the TRV's on the radiators, and I am wondering if it does not have a bypass, and there is not enough flow sometimes to stop the water temperature getting too high. I have turned the stat on the boiler down, slightly, and open all the rads fully, and I will see tonight when I get home if it is still running, (it turns on about 5, and I get home about 6).