Hi we have been waiting for our busy plumber to get back to us but we have been running our boiler for 2 weeks now on just the central heating and it is working fine lots of hot water (although not enough to fill a bath so sticking with showers) all the radiators are nice and warm, it is a pain not being able to put just the hot water on though, so Friday I turned off the central heating and put the hot water only back on, the boiler fired up but withing 5 mins the burner had stopped firing, the HL light was not lit but nothing was working, I turned off the hot water and tried to turn on the central heating but nothing was working at all, I decided to do some ironing and try again in 30 mins (I figured it had maybe overheated and needed to cool down) I then turned on the hot water switch and checked the light panel and the HL was finally lit so I reset the HL then ran inside and turned off the hot water and put just the central heating on again and it has worked fine since, so it is definitely a problem with the domestic hot water. Any ideas please ? Our plumber is calling later today I think.