Advice - 15mm gate valve to 22mm flow

[Ccw1971]

Two will work the 3rd might not

Is that due to going from the 15mm T up to the new 22mm new flow and return. Would it make a difference if it was all run in 15mm from the T off of the existing 22mm flow and return? Is it not possible to T off a 15mm circuit from an existing 22mm?

 

[ShaunCorbs]

Yes it’s like having a valve half shut

 

[Ccw1971]

Thank you