My EWT and LWT were colder than that.  My EWT right now is at 32 today and my LWT was at 29 or 30.  I had the technicians back out today and one of the technicians present worked for the distributor.  He did not like the fact my EWT and LWT were as cold as they were.  He wanted to know specific details pertaining to the length of my loop line in order to calculate if it is sized correctly.  He did say there could be other variables at work since it is a new construction. 

I couldn't afford another $600 electric bill so I did go against the suggestions of individuals in this forum and make the change.  I just received my electric bill yesterday for Feb 14 - Mar 15.  I made the change on March 1st and my bill is now 297.00 and I used 2,773 Kwh.  So for 15 days in this billing cycle my Kwh usage decreased by around 50%.  I would expect my Kwh usage to decrease another 50% if not more since it is getting warmer in southern ohio. 

Now, I just need to work with a few different parties now to make sure my horizontal loop is sized correctly.

Posted By paulmiller on 22 Mar 2011 04:20 PM 
The water temp coming in was 35.5 and going out to the field was 30.4 when the originally tested.

Is my loop undersized? or is this a setting issue on my tstat for why my electric bills are so excessive..

Climate Master design recommendations are 30F minimum. Your installers did you proud by exceeding that.
j

My installer came back out and retested the EWT and LWT. My EWT was under 30 and my LWT was around 28.. I am very concerned that my loop field is not large enough .
Right now I have turned the circuit off to my electric back up heater, as it seems like the electric system is engaging frequently to account for the $600 electric bills.

My installer is planning on coming back out with a manufacturers rep to look into this further.. So far, it seems like this has been a 30 grand waste of money.

Paul, if those are indeed you source temperatures, there is not enough delta between EWT and LWT, suggesting a problem with your refrigerant cycle. Your heatpump is not taking enough heat out of the water!

It appears my flow thru the heat pump was too high.. Today, My installer shut down one of the two goundfus pumps and was able to get the flow rate down to the proper level specified in the manuals. After correcting the flow level, we achieved a 6 Degree separation between the EWT and LWT. 32 ewt and 26 lwt. My only remaining concern is the EWT temp of 30 degrees coming in causes me to think my field is undersized for Mn.
Do I add additional soil on top of my field? extend my loops? Wait a year to see if this gets better?

No, 30 F EWT is good, no matter if Minnesota or South Carolina. So 30F and 6F delta with 1 pump disconnected means you are right on target. It will be much better next year, we see EWT go up 2-3 degrees in the 2nd year.

I have to differ - question this generalization.

30 is a most excelllent EWT for MN. It is a piss-poor EWT for SC. A loop making only 30 EWT in SC in winter will most likely fail miserably at making an efficient EWT in summer.

A reasonable design goal is EWT no less than deep ground temp -20 for winter; deep ground temp + 20 for summer. Occasional excursions to +/- 25 are OK.

I am not sure, geo heatpumps have a wide range of operation, the loops up north are sized for heating, the ones in the south are sized for cooling. So they swing more in SC, not really that detrimental for operation and efficiency.

OK - I'll concede that a system sized for cooling, undersized for heating in a warmish climate, might exhibit lower than design EWTs during a cold snap.