Feed and return pipes for oil boiler

Torq

Hi Guys,
How do you size feed and return pipes for an oil boiler? 3/4 to 1.5in, how do you decide? Is it relative to the number of rads, the boiler output, distance?
Thanks!
Torq

scudo2

Up to 90,000 BUT is normally 3/4"
Normally everything else domestic is 1"
Unless exceptional big house & boiler.

But saying that, It's critical to have the whole system properly zoned, piped sized and designed.

Simple to get right.
Total disaster if wrong.

corkgsxr

Iv never went above 3/4. But iv never done bigger than average house.

even then id only go inch till the manifold

Torq

Thanks for the replies! The house is a 2 story detached mass concrete construction from the 1930's of around 2k sqft. It will be split into 3 heating zones with hotwater, rads (up to 13) being supplied by manifolds with inbuilt flow meters and most pipework will be plastic. I don't know the output of the boiler, all I can say is that it's heavy! It's constructed in sections like the old Victorian cast iron radiators and has a Riello oil burner, again I don't know it's output but I can check it tomorrow.


The reason I ask is that I want to run pre-insulated ecoplex to and from the boiler but it only goes up to a max size of 22mm + 13mm insulation. Some of the run (8M) will be external to the house and about 1ft underground in a 110mm duct.

scudo2

Torq wrote: »

Thanks for the replies! The house is a 2 story detached mass concrete construction from the 1930's of around 2k sqft. It will be split into 3 heating zones with hotwater, rads (up to 13) being supplied by manifolds with inbuilt flow meters and most pipework will be plastic. I don't know the output of the boiler, all I can say is that it's heavy! It's constructed in sections like the old Victorian cast iron radiators and has a Riello oil burner, again I don't know it's output but I can check it tomorrow.

No need for details on boiler. Get rid of it. Install a "A" rated GRANT Condensing Vortex and save 35% on fuel.


ps. Most of us here are oil & gas installers so we try to give good advice.

Torq

Thanks again! Replacing the boiler is something I will get around to but just not at the moment. I want to get everything else set up and working first then I'll think about replacing the boiler.... once funds allow. But right now I want to get the pipework in so is 22mm +13mm insulation up to the job from boiler to manifolds etc.

corkgsxr

Use armaflex. Much dearer than the grey foam crap but its soo much better