Moved in to our recently (3 months ago) finished home in southern Utah; HVAC system comprised of a 2 Ton Earthlinked and 5 Ton Earthlinked DX system. I noticed the line returning from the loop field (5 vertical each 100 foot) was running very hot and this evening the unit stopped working. The 2 ton unit continues to work and the line returning from the loop field does not get that hot (typically very cool). First: the line returning from the ground loops shouldn't get blazing hot, right? Second: If it shouldn't get hot, how to diagnose the problem?

my first thought is compaction
Just to be clear the smaller line is the hot one, or are they both hot, or just the larger one

Is there a super exchanger ( hot water ) what temp is it set to .

I would start with getting the installer out there . Second hook a garden hose to the soaker line buried with the lineset , and start to soak the surface above the feild .

Horizontal or vertical loops (do we know)? If horizontal, what is the nature of the soil?
What were the conditions under which this happened (normal or extreme heat, or a long catch-up cycle as you first moved in).
I like the soaker hose idea.
Keep us posted,
Joe

Vertical loops with a ground temp around 55 degrees. The home is ICF construction and it was a warm day, but the house has been at 73 degrees for the past 2 months. The two lines that exit the compressor unit to the loop field: the larger one is ++++ho (too hot to touch) while the smaller one with the inline filter (looks like a fuel filter) was +++hot (could touch). Having the 2 ton unit in the same configuration (vertical loops in same soil) gives me something to compare to; the smaller line with the filter is always cool (subambient) to the touch regardless of long run times (tested last night with the 5 ton unit down.

Do you know what your entering and leaving air temperatures are? Also, what are you doing for ventilation?
J

Your 5 ton unit uses 5 100' vertical loops in series and the 2 ton has 2 100' loops in series?

Not sure what the entering and leaving air temps are, but the house is very tight with the ICF walls and open cell foam sealing the ceiling with blown in on top; the air coming out of the vents is in the low 60s; I imagine the entering air temp is in the mid-70s with the return air vents at the high points upstairs.
The line set exits the building and hooks to the two manifolds with five loops (parallel configuration?).
For venilation, we have ERVs on each system running continuously

Thoughts on using a condenser (without the compressor) interposed between the Earthlinked Box/Compressor and the ground loops to desuperheat the refrigerant? Not require the ground to take as much heat load (measured the hot line to the loops at 170F and the returning line 115F) - ground is sandstone.

Okay,
One thing at a time.
" Your 5 ton unit uses 5 100' vertical loops in series and the 2 ton has 2 100' loops in series?"
Jon R, Earthlinked is a DX system and 100'/ton vertical is one of the installation guidelines. If I remember correctly (don't do vertical DX), the book also permits 150'/ton (either 2- 75's or 1.5- 100'/ton). Can't do single 150' loops/ton as the refrigeration oil would not get recovered from that depth.

"Not sure what the entering and leaving air temps are,"
NTB, please find a probe type thermometer and get the return air and supply air temps at the air handler.

"Thoughts on using a condenser (without the compressor) interposed between the Earthlinked Box/Compressor and the ground loops to desuperheat the refrigerant?"
Let's first establish there is a problem (with the temps I asked for). If there is, then let's consult the installer or if not available the distributor before modifying system.

Earthlink systems act a little different than other systems due to the way they handle refrigerant. Much is designed around using as little refrigerant as possible and then of course recovery of oil from loops. Changing behavior/temp at one point may cause an undesired change/correction at another.

Joe

Sounds like the earth loop may not be correctly connected (grouted) to the earth. Are you sure the earth temp is 55? Where are you located?
It could be a problem in one of the refrigerant controls, too. Better contact the installer and make sure they do their due diligence.

In the St George area. The 2 ton unit is connected to the earth using the same technique and it runs cool (return line), however the two loops are a couple hundred feet away from the 5 ton loops and when we tested for appropriate depth we got into a little bit of water near the bottom; the five loops on the 5 ton unit all start 20 feet higher and we didn't get into any appreciable water, though the ground is moist when you dig down a few feet.
I have been told the ground is typically 55 degrees in this area.

Just so I understand: How does one test the refrigerant controls?

When we hooked up the pressure gauge/test set-up the pressures were: 150ish PSI on the one line and 325-350 PSI on the other line. The temperature of the large line heading to the ground loops was 190F; the return line (smaller) was ~120F.

Have you started soaking yet?
What did the installer say?

After 3 months none of this is your responsibility , I would say that the likely hood that its loop to earth contact or lack there of is over 90% .
A malfunction in the refrigeration controls , I assume was inferring unequal distribution to the loops , which means dig to diagnose .

You measure the charge by looking at the level through the site glass.
When you say we hooked up the gauges, who's we? If that doesn't mean your original installer, you are risking your warranty. Pressures are going to be high if temps are high.
How is it that you can measure pressure, but not entering/leaving air temperature?
My suspicion is the link to the ground (grouting) or loop sizing, but you need your installer involved. It may be that the 2 ton works better simply because it is not as tightly sized.
How many of these has your contractor installed?

Tuffluck,
Do you know the area, is 100'/ton common?

j

The bad grout makes sense - also, your loops are probably in parallel and some of them may be pinched or obstructed.  That creates  flow but poor performance.

jonr....you really should stick to giving advice about things you know.

Earthlinked  loops are supposed to be  hooked in parallel.

Also it would be almost impossible to hook them in series with the factory built manifolds.

Is there some part of "probably in parallel" that you didn't understand?  Or do you think that it is impossible that something was done wrong/non standard on a loop that doesn't work?

If you have no ideas, maybe you should just say nothing.

If the field is to blame,
series would be hard to do, as the the make-up of one loop is 1/4" and 1/2" copper pipe tied together.

Grouting, debris or brazing plug could be the problem.

No advice is better than bad advice which you seem to give a lot of.

You have been asked several times on this and other boards what your back ground and qualifications are.  We still are in the dark.

It is obvious from your posts on this thread that you know very little if anything about DX systems.   If  you want to be taken seriously by the professionals here,  you probably should give some info about who you are and what qualifies you to be giving advice.

No doubt there is something wrong with the OP's loop.    The configuration  ( series or parallel ) is not one of them.

The loops are hooked to the Earthlinked manifolds with each line set/loop 7 feet from the center where the manifolds sit; the installer did the pressure check and noted too much freon in the middle or top site glass and reclaimed it. I have uncovered the manifolds/loops and he will be by to check them. Is there a non-invasive way to check that each loop is functioning? (Temperature delta?). Thank you all for your input - I will keep you updated and will continue to appreciate your expertise.

Due to the limited reach of a compressor to recover refrigerant oil no DX systems are piped in series. Personnaly I've always found the reach impressive (100+ feet) but it is not without boundries. This is why DX systems offer little field design opp to the installer (check 1; vertical, horizontal, 100 or 150'/ton), they simply put as much in the ground as the unit can handle.
Advantage or disadvantage is in the eye of the be-holder, but limits have an impact on uses. This is among the reasons (IMHO) for the continued popularity of the older water source technology.

Jonr, not knowing what you don't know is a limit as well and not without impact. While I confess here and elswhere I often seek your latest contribution first (I'm not opposed to lively debate), there are times when you are so far afield that I worry that a thread author may mistake you for a geo authority. I suspect the suggestions to qualify your comments will get less gentle if you are unwilling to recognize and confess your own boundries.
j