hi does anybody know anything about these boilers my sister has one and it stopped working asked me to have a look. on the panel when you turn it on the light goes green as it should but on the part which has the heating symbol above it the light is yellow which shouldnt be on, i had a look and the flow and the return off the boiler were dripping so tightened the nuts (would the boiler shut down if there is a leak of any sort in the system?) this didnt solve it- or is the pressure gone to low and has to be built back up? i turned the valve on the auto fill but the gauges didnt seem to move? any ideas?