hi all, just wondering would anyone know how 2 fix a heating problem. I have a Ferroli optimax boiler, a sealed system and only have it since 2009. however on a few occasions it stopped working and i got the error code F37, most times with a lot of fiddling about....i.e. turning off rads.. .turning on taps eventually it would kick in and start. But not this time I'v looked at the manual but its saying something about the pressure.....but i cant get it back up to 1 or 1.5 cos what i normally do is turn the valve and the guage bar moves but this time doesnt budge at all and btw my first time here sorry if this seems more like an essay any info would be greatly appreciated