Hi,

 I have been researching for our install this summer, new construction. I am mechanically inclined with electronic/computer skills as well. I understand most of the GSHP terminology but have a few holes in my knowledege. 
3000 ft2 house, super insulated with air to air heat exchange, don't plan on electric backup, wood heat for the extreem cold.

 These are what I am considering. 

http://cgi.ebay.com/2-Stage-Geothermal-Heat-Pump-4-Ton-w-DIY-Vert-Loop-/150572821931?pt=Air_Conditioner&hash=item230ed6edab

4 ton vert loop kit, $7558. 
Is the flowcenter neccessary?


http://cgi.ebay.com/Geothermal-Heat-Pump-4-ton-2Stage-Tax-credit-seer-/220754723425?pt=LH_DefaultDomain_0&hash=item336601c261

Furnace alone, $5589, seems like a very good price. 


I have seen 350 feet of water column for a 4 ton unit on this forum, would that be sufficient in northern Minnesota, or does a water temperature measurment need to be taken?

I'm sure I'll have more qaestions

 thanks in advance
       Steve

Is the flowcenter neccessary?

Did you have another plan for circulating the fluid in the heat exchange loop?

Considering that you are on the raw edge of familiarity with a geo system, you might consider buying an all-in one kit. That way, you would have some minimal expectations that the components would all be compatible.

You also need to find a way to make sure that the system you are buying is properly sized for your heating needs. That would probably entail finding out what your heating needs are. You might ask the place you are considering buying the unit what resources they have available to analyze your home.

Steve, what's your energy model say is the design temp heat loss for the house. For 3,000 sqft and "superinsulated" your selection of a 4-ton system seems twice what ought to be needed. What is it about your house that is "superinsulated?" Did you have a blower door test done, and if so what was the result?

For reference my new (superinsulated) house is about 4,000 sqft of conditioned space has a design heat loss of about 21,000 BTU/hr. After the first blower door test came in at 400 cfm at 50 Pascal depressurization, the heat pump was specified as the CM 2-ton unit (TT series, model 026). Their tables show a capacity of 25,400 BTU/hr with 6 gpm and 50 degree incoming water temp.

When you say you have 350 feet of water column, is that for a standing column well design, from pump inlet to return depth? On a per ton basis, you're in the ballpark. You need to have the water quality tested for suitability for SCW.

Steve you need to start with a heat load calculation.
j