alpha.C28.i can get the radiators warming up but no hot water to the hot tap.i have tried on heating/water setting,and on water setting on its own,no joy
There are a number of us who probably can help you diagnose this and potentially save you a plumber's bill, but we are gonna need more info. What boiler have you got (which will tell us whether it is a Combi system or not)? Or tell us if you have a hot-water tank in the airing cupboard. I assume Apha C28 doesn't mean anything.
I'm having a similar problem with my Vaillant combi. The only way to get hot water to the taps is to set the central heating thermostat to come on and heat the radiators. I've been told it's a problem with a diverter valve that needs replacing. At the moment it's only a slight nuisance but soon I won't want the radiators on at all. Methinks we both need a good plumber......good luck.
Sounds like a motorised valve or cylinder thermostat (not immersion heater stat) problem to me. It would be useful to know what valves you have - either one for heating plus one for water or a mid position valve i.e. just one valve for both. Maybe there is no cylinder stat at all which will rule out one cause.