Well i got in from work about 5, had a hot shower etc...chilling out and felt a bit cold, radiaters more or less cold, so i checked my combi boiler and the water temp is zero, pressure is zero, i ran the hot water tap and it was freezing and the boiler didn't fire up either. I drained that nob thingy that you twist, re pressurized it to 2bar, turned boiler off then back on and flame kicked up ok, water temp started rising to 40c so i chilled out again. Checked radiaters after an hour still luke warm only, checked boiler again, zero pressure, water temp 20c - anyone any idea what i can try, boiler is a Vokera make, im off bed now and cant get online till tomorrow evening if yer can give us a clue, cheers!!