Honeywell 22mm motorised valve to 20mm composite pipe

Morning.
As per title, plumber few years ago used 20mm composite pipe (https://www.screwfix.ie/p/purmo-per...te/364hr#product_additional_details_container) to replumb part of the central heating. He fitted a Honeywell 22mm motorised valve (https://www.screwfix.ie/p/honeywell-home-v4043h-2-port-motorised-valve-22mm-22mm-compression/31480) onto this 20mm pipe

I want to add an other valve.

How would you connect 20mm pipe to 22mm valve? is there such a thing as 20mm compression olives?

 

He would have most likely used a 22mm x 20mm reducer

 

No, he didn't. He only used 20mm pipe-compression nut + olive - 22mm valve

There are photos in this thread, though may be hard to see the motorised valve connections
https://www.diynot.com/diy/threads/...ge-to-3-4-bsp-male-cylinder-hw-outlet.557158/

Post #14

 

Wow, what a lash-up. A photo of the actual valve would help, but generally you'd use something like this https://www.wolseley.co.uk/product/uponor-compression-adaptor-brass-20-x-22mm/

The difficulty with zone valves is that the cap nuts don't use standard pitch threads, so you might not be able to use the nut from the adaptor.