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[jdruhnke]

I'm having troubles figuring out the size of pumps i need for my application.  I was recommended Gundfos Pumps because you can replace parts of the pump if it goes bad rather than buying a whole new pump.  However i have no clue what pump to get.

Is there an graph that would show distance with pex size and how much HP my pump should be?  I've tried searching the forums but can't find any related posts, which surprises me.

200ft round trip for the house
70ft round trip for the shed

[caper]

hey pal, no expert here , but I have a similar set up, use a grun 2699 for the 200 ft run and a 1558 for the shorter run, you will have no issues.....

[GCTerpfan]

I recommend looking at this link: http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf

It seems kind of intimidating at first but if you go through it step by step its not too bad.  The TACO pump curves are shown but you can use the head calculation you get to look at any manufacturer pump if you can find their pump curves. 

I have a really long run of 1 1/4" pex, and a TACO 009 pump.  I went through this sheet and calculated I was getting just shy of 7 gpm of flow.  This weekend I pulled a fitting off and timed how long it took to fill a 5 gallon bucket. It took 45 seconds which is 6.66 gpm. So if you do it right it does work.

[RSI]

Unless you have a lot of fittings (especially elbows) or restrictive heat exchangers (such as a 10 plate) Grundfos 15-58 pumps should work for both.
If you have a large house, you may want to go up to a 26-99 for the house. Low speed on the 26-99 is just a little more that high on a 15-58.

[LittleJohn]

If you are going Stainless or Bronze (for open system), here is a suggestion -> Go with a SS Alpha about the same $$$ as a SS 15-58, but you may be eligible for credit from power/gas company.  PLus it has a readout on energy usage and GPM -> can be helpful down the road WHEN if problems arise.

[LittleJohn]

jDruhnke,

Here is my setup and about what I run for GPM;

Main house (3500sf - All in slab, or heat emission plates, and a side arm), no more that 200' round trip of 1-1/4" PEX, with a SS Alpha running between 5-8 gpm depending on which setting
Detached garage (4000sf - ALL IN SLAB), no more than 125' round trip of 1" PEX,with a SS Alpha running between 3-5 gpm depending on which setting

I have FPHE in both building and heating them has never been an issue, once I found a couple of gremlins (STUPID CHECK VALVE, and a little faulty wiring  on thermostats)

...also I tend to stay away from 26-99's just because of the large power draw.  I know they have there applications, and I do have one installed as part of a Snowmelt loop I have installed (haven't turned it on yet, too afraid I will have to stand at boiler and THROW wood in all the time  )