I think you mean the green bit is plastic - which I confirm by looking at the one I got from BES. That's actually the CH outlet, it doesn't go to the pump.
There are only 3 variations of these diverters really, other than changes to microswitches or rotatable parts. Those three have the inlet/outlet ports in different directions on the brass diverter casting. I don't think you'd be any better off with the part you're thinking of (from BES). Whether the original Giannoni DV's, assuming this isn't one, are any different in their resistance I don't know, but I doubt it.
The resistance is determined by the gap left when the moving parts move (red)
I haven't bought a giannoni of this type recently, but not that a similar DV for an Alpha boiler (£100+) also has the green part in plastic.
Give BES a ring and see what they know...!
SEE HERE
There are only 3 variations of these diverters really, other than changes to microswitches or rotatable parts. Those three have the inlet/outlet ports in different directions on the brass diverter casting. I don't think you'd be any better off with the part you're thinking of (from BES). Whether the original Giannoni DV's, assuming this isn't one, are any different in their resistance I don't know, but I doubt it.
The resistance is determined by the gap left when the moving parts move (red)
I haven't bought a giannoni of this type recently, but not that a similar DV for an Alpha boiler (£100+) also has the green part in plastic.
Give BES a ring and see what they know...!
SEE HERE