Central heating pump size
 

Hello all,

I have recently added a further 3 radiators and an additional 14m
approximately of pipework to incorporate an extension.

I have been to a site where it indicates the flow required and the BTU that
the pipe size can manage etc but there was no indication of the pump
requirements. Apart from a "suck it and see" scenario is there anyway of
calculating the pump specifications? How do builders determine the correct
size pump for a new installation?

Mark

Central heating pump size
 

Mark wrote:
is there anyway of
calculating the pump specifications?

Yes. You calculate the required flow rate from the heat loss
calculations. You then calculate the frictional losses in the pipe work
along the index circuit (usually furthest rad fom the pump) from the
required flow rates, the pipe diameters, the pipe lengths, the number
of fittings, etc.. It's fairly tedious number-crunching.


How do builders determine the correct
size pump for a new installation?

They put in a UPS 15-50 Selectric. If that doesn't work properly, they
put in a 15-60 Super Selectric.

Central heating pump size
 

Aidan wrote:
Mark wrote:
is there anyway of
calculating the pump specifications?

See Appendix H of this:
http://www.cda.org.uk/megab2/build/pub33/33_2000.pdf

It gives data on pressure losses per m for pipes and the equivalent
length of fittings.