I bled my radiators yesterday as the tops were only getting warm but bottom was nice and toasty. Problem is, I did it with the heating switched on as thats how I thought it was done. The pump started squealing in my combi, and now the heating and hot water doesnt work at all. I switched everything off, and bled it all again, then turned it back on, but as soon as I manually turn the heating on, or turn a hot water tap on, the pump sqeals for a second, and the heater ignites, but then switches itself back off. Boiler is a worcester 28cdi, and was serviced annually until I moved in 3 years ago

Any help very much appreciated, as I cant find a definative answer online. Cheers.