circulator sizing for outdoor wood boilers

[midcoast]

Hello all
I'm installing a wood boiler 300 feet away from the house. The boiler people say that 1" PEX piping is ok and that a Grunfos 4375F or a Taco 0013 will move enough water for me. I'm looking to use about 150000 BTU/HR. I'm not sure that these circs are big enough to move 15 GPM through 1" pipe. Does anyone have any systems that are this far away and are moving this much heat? Any help would be great.

 

[BrownianHeatingTech]

300 feet away is a 600 foot loop length. At 15gpm through 1" pex, using 30% glycol solution, that's about 200 feet of head. Not going to happen.

1.5" pex would be the bare minimum for that loop, and even then, you'd be looking at a large pump (about 30 feet of head, at 15gpm).

Two parallel runs of 1.25" pex would get you down to about 20 feet of head. There's a good chance that two pairs of 1.25" pipe would cost less than one pair of 2" pipes. Dealing with only 20 feet of head would certainly make your electric meter spin slower, too... (and reduce the cost of replacing the pump, when it eventually wears out)

Joe

 

[Piker]

Brownian,

Where do you get your specs for head loss in pex?

cheers

 

[midcoast]

boiler is water only not anti freeze

 

[BrownianHeatingTech]

Where do you get your specs for head loss in pex?

I have a computer program that does it.

If I recall correctly, Taco has a .pdf file that describes how to calculate it, manually. Some of the manufacturers also have charts for their product.

boiler is water only not anti freeze

Then it's about 160 feet of head for 1" pex, and about 25 feet for 1.5" pex. So, if you get true 1.5" pex (not all brands are sized the same - some use outside diameter, so the actual inside diameter is smaller), you could squeak by with a large pump. A pair of 1.25" runs would get you below 17 feet of head.

Joe

 

[Rick Stanley]

Here is a sizing link , I think Heaterman had posted here, , that's pretty straight forward ..............

http://forums.invision.net/Attachment.cfm?CFApp=2&SelectingCirculators;.pdf&Attachment_ID=34443