To switch the feed to my rads between heat pump and thermal store I need a 22mm motorised 3-port valve. Ideally it would have a centre off position so I do not need a separate 2-port valve as well. Does anyone make such a thing?

Funny thing I just looking at ESBE website vrb140, actually a 4 port, takes a flow from two sources and can mix or isolate and take from one or the other.

 

Not sure how you would control

Thanks. Not sure whether it is suitable, there are pix here and here which I don't really understand. Nor why it would be described as enabling the use of two heat sources. Seems expensive even before you add an actuator.

 

I may have found an alternative way of doing it now. Two people have replied to say the Vaillant HP de-energises the heating valves when it is calling for DHW, so actually the S-plan valve setup I already have should work fine even though Vaillant technical have advised against it.