Hi can anyone assist with my heating problem please, came back off holiday 17th sep turned on the boiler for hot water and it will not heat up, my initial response was that the 3 way valve was not working! well i have looked every where i can think of and havn't found one, the tank stat has been replaced, to no avail, it is an ideal rs460 probably original when house built about 1965, gravity feed. HELP!!! 
