How Many Radiators off 15mm Pipe?

[otronics]

Hello.

A few years back when my central heating was installed, the plumber ran flow and return pipes to the loft for future use (loft conversion).

However, these pipes are only 15mm.

Ideally, I would want to run 2 radiators and a towel rail off these.

How many radiators (or BTU might be easier) could I run off 15mm?

Thanks.

[arco_iris]

I am amazed that no other member has yet answered, I saw this yesterday but did not comment then as do not feel qualified to do so.

As far as I am aware, DIY, you will not have any problem with connecting what ever number of radiators/towel rails you like....

to your 15mm pipes, central heating systems can be piped in 10mm or even 8mm pipes and still work fine. Just keep flow side connections and return sides separate, that is, in parallel not in series.

Its all about circulation, not volume of flow. I stand to be corrected, of course.

BTU calculations are from the size of room to be heated (surface area of radiator) and don't come into this (excepting boiler temperature of the circulating water).

[otronics]

Thanks.

Anyone else have anything to add?

[wine~o]

2 rads and a towel rail should be OK, for a larger run though 22mm flow and return and 15mm tailed off to each rad.

BTW microbore is sh1te IMHO