Radiator pipe size

[breakwater8]

Hi
Could someone tell me if you can install a rad with 15mm chrome plated copper pipe from trv and then reduce it to 10mm copper before it get to the flow and return pipeline ( would this change its performance and is it common?

 

[kevplumb]

it's ok
if you are gonna use soldered fittings or pushfit you need to remove the chrome from the joint area