Ok to increase diameter of pipe in unvented heating system?

[The Plumber Guy]

Hi all, I'm off to Reading this weekend to help a mate out who wants a couple of radiators moving. Unfortunately he's just moved into a newer house with 10mm microbore pipe running down the insides of the walls and for one reason or another the pipes can't remain hidden between the old and the new rad (distance moved will be 2000mm). To make the new piping less conspicuous and nicer looking I want to increase the pipe diameter to the more rigid 15mm. Is there any reason I shouldn't do this or should it work as normal given that it's unvented and therefore higher pressure? Cheers all

 

[Simon F]

no problem with increasing the pipe size.
Pressure in the system is not really a factor, it is all to do with resistance to flow.
there is the possibility that the system could need rebalancing afterwards especially if other radiators are still in 10mm pipe.
up sizing this one could then starve them, something to have in mind.

 

[Phil_Plumb]

TBH why would you upsize? 10mm modern heating systems transfer the heat so much more quickly than 15mm tube, as there is a lot less water to shift!

 

[tamz]

Guy are you really a plumber?

 

[SimonG]

Guy are you really a plumber?

To the point, but true.

Unvented would be a sealed system? Leave it in 10mm.