15mm v 10mm

[dormermike]

What benefit is 15mm CH piping vs 10mm as a heat carrying capacity, if lockshield is only opened a wee bit?

I have a 15000 btu rad supplied by 10mm tails, with lockshield open 1 turn..
Is 10mm the limiting factor or LS?

RGI told me that 10mm is too small for this rad, but it gets proper hot. LS not fully open either .. hence my asking.

Cheers

 

[D_Hailsham]

It all depends on the temperature drop across the rad. If it's 11C, the absolute max you can put down a 10mm pipe is 4Kw (13,600BTU) but if the difference is 20C you can put 7.25kW (24,800BTU) down it.

If the 10mm pipe is replaced by a 15mm you will just have to close the LS valve more to get the correct temperature drop across the rad.

 

[dormermike]

It all depends on the temperature drop across the rad. If it's 11C, the absolute max you can put down a 10mm pipe is 4Kw (13,600BTU) but if the difference is 20C you can put 7.25kW (24,800BTU) down it.

If the 10mm pipe is replaced by a 15mm you will just have to close the LS valve more to get the correct temperature drop across the rad.

Once again a very interesting reply from you d_hailsham - thanks! I think i understand but will google for more info.

Was half expecting someone to tell me i need a new boiler haha

 

[D_Hailsham]

I forgot to give you a link which explains it in more detail.

Read Small Bore heating Systems