Maryland Integrating New DX Heat Pump into Existing System - my story

Background :
When my new home was being built I specified that the HVAC be a Geothermal DX system. My builder contacted Advanced Geothermal of Reading PA to do the install. It was for a 3 1/2 ton system geothermal Comfort Aire heat pump (r-22) and a Trane Air handler.

The company drilled five vertical holes down about 200 ft, fed copper tubing loops (one side insulated) down each bore hole, and then connected each loop to a manifold - that fed the lines back/forth to the home's heat pump. They back filled each bore hole with sand. Note: at that time, Oct. 2004 they weren't using grout (at least in this area).

Problems - first cooling season - Summer '05

When the AC season got going, our unit' s compressor kept going out. We called our service company. they claimed it was the high pressure switch. They replaced it, but the compressor kept going out. Then one of their Techs came in, and per the owner of Advanced Geothermal, made changes to the units internal piping (not sure what). They also installed an automatic drip line (to moisten the soil in the bore holes) on top of the manifold, plus installed an outdoor access pipe (above the manifold) so we could add water via the hose - if needed). This was toward the end of that summer and appeared to help.

Summer '06
Again we had problems during a prolonged hot spell. It was the high pressure switch again. The tech from year before had retired. New tech ripped out all the new piping old tech did, restoring heat pump. Advanced Geothermal advised them to use a pressure switch with a higher setting.. System now worked, but in September, high pressure switch failed. It appears they just added a Ranco switch for temp control, but I cannot see where they put in new pressure switch. They must have right?

Either way, we had no further problems with the System until December 2013.

December 2013 - three way switch failed (hot water Desuperheater).. We opted to postpone getting it fixed since the estimate was about $1500 for parts/labor.

March 2015 - Compressor fail - told windings bad. Given quote for new compressor. That and 3 way valve fix added up. Wanted to compare to new unit cost with incentives. Received two quotes, one from Advanced Geothermal, another from Earthlinked. HUGE DIFFERENCE! Went with Earthlinked - total cost after incentives wasn't too much more than repairs to old heat pump. .

Of course Contractor then wanted to sell us other things... questioned the vertical loop field. He asked if they tested the soil, used grout, then said we should have anticorrosion system for copper tubing, said we should have grout.

My response - it's worked for ten years with old heat pump. And our soil isn't supposed to be acidic.

He installed new heat pump, integrating it into existing system. Sucked all the old freon and as much of the old oil out as possible. Before adding new r-22. Had everything running back in mid-may. But said the vertical loops were not conducting the heat transfer as well as they should. He said the AC cooling mode was heating the ground up too much, and that in heating it was taking too much heat, said the system would not be as efficient as it should be.

I told him I wanted it to work as well as the old one, that was all. Then he said it might trip the highpressure switch. I told him of tthe problems with existing heat pump, and that somehow they fixed it from reoccurring. This was mid-day. We used the AC cooling mode off and on this Summer with no pproblems until early August - then compressor went out at high temp switch.

I reset the switch. An hour or two later, compressor out again. This time high pressure switch. Now it's time to call contractor. I'm not going to keep resetting unit.

They got the old heat pump working, but how? I really don't think they bypassed the high pressure switch in its entirety, at least it does not say that on my maintenance receipts. And I'm not sure I can call my old company up and ask them - would they even tell me?

I can't afford to dig new vertical bores, nor take the old ones out just to grout them. I've been retired on a Disability and now on fixed income, it takes me mmonths to save up any kind of money.

I know, and apologize for the long post, but what do you all think is my best option?

Thanks,

K. R. N.

 

Sorry to hear, but your story is typical for DX systems. It also does not help if one line is insulated. High pressure is a typical strain on the compressor. I had 7 owners calling me last winter with failed DX systems. Either compressor or loop failure. Unfortunately I cannot offer much help.

 

Thanks for replying.

I've been in contact with their sales rep for my area. He's the one who thought I'd have zero problems with integrating the Earthlinked unit with my system. He still believes it should have worked. So I asked him to get me a second opinion and he's going to check it out for me. I also want a second estimate if they insist on doing new ground loops. I don't want to depend on one contractor, especially if I don't really trust him to treat me fairly.

I do want to say that the original system, once they ironed out the bugs, worked flawlessly for 8 years. Where neighbors and friends were paying over $1000 in electric bills during the coldest months, ours were under $250. So yes, I was very pleased, even though it was not as efficient as I thought it could have been. The same for high cooling season, we saved a lot. But now all those savings are going to another new system. Sigh....

 

The difference is that buried HDPE pipe is have a 100+ year life expectancy, and we give a lifetime warranty for the homeowner. something which is not the case for DX.