Hi

My Baxi 105HE has started leaking. I've taken the front off and looked behind the control box, and it looks as though the leak is coming from what is described in the Baxi Installation & Servicing Instructions as the 3 Way Valve Assembly, specifically the DHW Pressure Differential Valve (seems as though the water is coming out of where the small pushrod comes out of the front).
Do you reckon it may just be something like the diaphragm, or will I need a new DHW Pressure Diff Valve, or will I need the whole new unit ?

Any help appreciated before I call out an engineer.
Cheers.

Cheers Andy, I'll try that first.