CNYgeo - Good point...come to think of it, I do remember seeing lower COP values on the old GSW units. I can only imagine what kinda COP the THW high temp (up to 145 or so) water units are putting out...probably not that good. I put a TekMar outdoor reset in the buffer tank. My geo unit talks to it, and my thermostats go to their own manifold/pump via a switching relay. I think I have it set for roughly 85-100 degree water...we put in mostly braz. cherry floors, and it's suppose to be about the most unstable wood there is (wife's choice!), so I can't run very high temps. The desuperheater pulls/returns water to the buffer tank, so water is going into it around 85-100, so no wonder it 160 coming out.

Joe - To the average person I probably border on overbearing, but I feel like I'm more working with my installer than bugging him per se. He's not particularly strong at math, whereas I studied the book so as to help diagnose and make sure things worked properly and were in spec when he was done. I'd be more understanding if it was me and my buddy putting this in...I hired a professional so as not to have to be so hands on. It's actually worked out though as I feel as though I have a pretty good understanding of my system at this point. After learning what all goes into it, I have a better appreciation of how many things there are to potentially go wrong...more than meets the eye for sure. One thing I hadn't thought of prior that struck me today was loop field placement. If I had it to do again, I'd have gave more thought to placement. The loop field is to the north side of my house, which casts a shadow over a good portion of it each day. Had it been in the wide open sunlight, it may have given me a bit more efficiency.

TuffLuck - Yep, he topped it off! It is 410A, and it's the same brand as he used before. It's only a 1 year old unit, so I'm not sure if it's as big of a deal as a older model or not. I'm not sure if the leak was from whatever overheated (some sort of pressure release maybe?) or what. It was the radiant unit, so it's not like it had a real long lineset like the forced air to try and find a leak.

HeatlessInHarrisburg, at least in cooling season the shade will help. Hope the blizzard goes around you. :-)

What "curve" do you expect to see? I've got all the other data - I just threw this out there to illustrate how much compressor power can vary for a W-W unit. Correct me if I'm wrong, but I believe leaving temp is most relevant to compressor load as it is most directly related to condensing temp and therefore pressure and compressor power. If you're interested in seeing something else, let me know I can start another thread so as not to hijack this one.

The point of not just topping off a blended refrigerant is not that you don't use the same "brand". Rather, when a blended refrigerant leaks, there's no way to tell that the blend is still the same, and that it won't affect the performance of the equipment it's in. Maybe it's not as critical with 410a...

As a side note...is it just hear say to me, or have others of you heard that 410a is on a phase-out list, too?

OK to top off 410a, just make sure the tank is inverted so as to introduce only liquid refrigerant.

What loop placement factors are worth considering? Say you are primarily interested in heating.

Southern side of a hill
No shade
Dip/trough in the ground (to collect rain water and increase soil conductivity)
Winter ground cover (for insulation), cut short in summer/fall.
Wet area.


Do any of these make much difference?

Interesting question. I know that the frost certainly comes out of the ground in the spring much quicker in areas with full sun. So presumably you might get higher loop temps earlier as winter turns to spring if loop field is in full sun. But maybe at the depth of the loop it's not a noticeable difference.

If it does make a difference then it might have an offsetting negative effect in the summer for cooling.