sink plumbing advice

[RstJAB]

Hi,
I am plumbing in a new kitchen sink this weekend and just want to check a couple of things.
Do I need to install a non return valve on the hot water supply if I have a combi boiler (and therefore no hot water tank)

Also as I am doing this myself are compression coupling ok for all the connections or do you recommend something else.

Thanks for any advice

Richard

 

[Nige F]

1..no 2 yes

 

[RstJAB]

Thanks Nige!