Re plumbing fresh water.. push fit, 12mm or 15mm ?

[StefanSG]

I am replacing 15mm copper fresh water system with push fit. Its available in 15mm or 12mm (ID 9mm). 12mm is cheaper and presumably more flexible, will it throttle the volume of water ? Jabsco PARMAX 2.9 pump 11 litres per minute?

Thanks, SSG

 

[Bodach na mara]

My system is 12 mm and, if it throttles the flow, most of the time I don't notice it. I also have a Parmax ll l/min and it fills my domestic size kettle just as fast as I do it at home. However the galley is only halfway along the pipe system and I do notice slow flow from the heads faucet at the end of the run.

 

[Boater Sam]

I would use 15mm, its the domestic standard in the UK and hence bits are available everywhere. There is also a larger range of fittings.
Remember that with push fit you need inserts at every connection which further reduce the flow.

 

[Bodach na mara]

The OP is stripping out a 15mm copper system. I read into his post that he intends to use push-fit. Probably because it is quick and easy, unlike copper. I had to renew bits of mine to repair frost damage. Because the existing system is 12 mm I continued in the same for the bits needing renewed. Had I been starting from scratch, I probably wouldn't have changed.