Boiler loop circulator pump sizing for "equivalent length of pipe"?

[JohnDS]

I am piping out a hot water condensing boiler that has its own boiler loop and circulator pump aside from the heating system loop and circulator pump. The manufacturer supplied a recommended circulator pump for the boiler loop which is sized for "50 ft. of equivalent length of pipe". The instuctions go on to say that it may require a higher flow circulator pump if you pipe it out more that "50 ft. of equivalent length of pipe". It then gives a chart of how much each fitting and valve is equal to as a length of pipe. My question is, do i size the circulator pump just based on the fittings and valves equivalent length, or do i also add up the amount of actual pipe in between each fitting and valve to come up with the amount?

Please help, im not understanding this. And since it is a condensing boiler with a small heat exchange it is important that it has the correct flow and doesnt overheat so i dont want to ruin it. Thanks guys for any help.

 

[chukar]

I am piping out a hot water condensing boiler that has its own boiler loop and circulator pump aside from the heating system loop and circulator pump. The manufacturer supplied a recommended circulator pump for the boiler loop which is sized for "50 ft. of equivalent length of pipe". The instuctions go on to say that it may require a higher flow circulator pump if you pipe it out more that "50 ft. of equivalent length of pipe". It then gives a chart of how much each fitting and valve is equal to as a length of pipe. My question is, do i size the circulator pump just based on the fittings and valves equivalent length, or do i also add up the amount of actual pipe in between each fitting and valve to come up with the amount? Please help, im not understanding this. And since it is a condensing boiler with a small heat exchange it is important that it has the correct flow and doesnt overheat so i dont want to ruin it. Thanks guys for any help.

A decent pump should be a three speed for a line, but sizing it requires know what is going to be on it, also the size of the piping, also how it's pipe, are you doing primary secondary piping or is there only 1 run. When measuring the length it's total length of pipe plus fittings it will be the same way you determine what size venting to use for the exhaust vent.if you have time there is a book to buy "pumping away" by Dan holoadan.