Pipe Sizes

[johno12345]

I must be having a thick spell. I cant get my head around some pipe size calculations.

I have a studio, 50mm insulation timber framed building that I am going to extend my existing boiler to cover on a separate zone.

The pipe run to the furthest radiator is about 14m

For reasons of space, I'd like to use the smallest pipe possible, so 10mm pex.

I have run a few calculators and seem to get between 2kW and 5kW of heat required. I already have two spare radiators that I would like to use. They are 2.2kW and .83kW I have two of each spare.

the boiler is a 30kW condenser and is plenty big enough for the extra load.

any help here would be most appriciated

 

[BigSnoopy01]

follow the plastic pipe manufacturers guide for pipe sizing. 14m is probably to far really for 10mm pex which has a inside of about 6-7mm. 15mm well lagged min would be my guess.