baxi 80e ,water and heating on together problem ??

[keeny]

can anyone help me please. i have a baxi 80e that is about 4 years old . the problem is that the radiators are coming on with the hot water when the switch is set to hot water only ?. when you turn the hot water tap off the boiler stops as it should and 3 seconds later, kicks in again heating the rads. i have to keep turning boiler off, and back on when and as i need it. ive changed the board and the diaghram but still the same ? any help would be much appreciated....cheers keeny

[toscal]

There may be something now trapped in the diaphragm valve thingy preventing it from closing properly. Might be worth dismantling it again and checking. Is there any water coming from the overflow valve.

[keeny]

There may be something now trapped in the diaphragm valve thingy preventing it from closing properly. Might be worth dismantling it again and checking. Is there any water coming from the overflow valve.

I did give it a good clean before i fitted the new diaphram, could it be the smaller diaphram on the unit that i need possibly ? cheers keeny