Hi I have a baxi 80 eco boiler which has been working fine but now the central heating is going even when in the hot water only mode the front valve on the diverter comes out when you turn on the taps and goes back in when you turn the hot tap off. The top rear valve comes out and stays out unless you turn off the powere supply then it returns in. is it the diverter valve thats gone or something else . HELP PLEASE