Seems as though another DX Manufacturer is proposing a 2-stage series. Earthlinked unveiled its new series of DX HP's last week, and promotes 2-stage technology. Now without any real performance specs in front of me, I am left having to make some assumptions on the equipment. It seems as though Earthlinked took a page out of Maritime Geothermals/Nordic technology and now oversize their earth loop systems coupled with undersized compressors. What I mean is that no longer is there a 2 ton, 3 ton, 4 ton, 5 ton, and 6 ton size, rather we are dealing with 020, 030, 040, 050, and a 060 compressor. From what I can gather, they will be specifying that the 020 has 200' or more of loops, the 030 have 300' or more of loops, etc... My understanding of 2 stage DX compressors was that they failed in the field. The refrigerant simply would not travel at a high enough velocity at part loads to keep the oil entrained. Compressors failed, and had to be replaced with single stage compressors. Notwithstanding the general opinion of DX that is out there, what is the forum's thoughts on another DX manufacturer attempting to produce 2-stage compressors?

With computer controls to occasionally step up the speed to move the oil, it might be OK. Or valves to briefly isolate portions of the loop (forcing higher velocity in the remaining loop). Or perhaps new refrigerants and oils stay mixed better.

R-410a refrigerant is being used. Interesting to see if they have computer controls integrated.

I'd rather they started with fundamentals like getting their product recognized by the code.

I agree Joe with your sentiment regarding the code.
but since no one has held their feet to the coals to do so, I think it will remain a mute point.

I am very interested in seeing how they plan on integrating this technology using DX loops. I can't help but be afraid that they are ignoring some fundamentals of refrigerant properties in trying to do this.

I know you are one of the good guys and I don't want to beat a dead horse, but I think the problem is more systemic (DX manufacturers at large not just this one): Ignore code protocol, ignore refrigerant properties, apply universally in spite of limitations, ignore that they used to say the loops couldn't be longer due to oil recovery and now they have to be longer, ignore best practice and put it in the field at consumer expense.....work out bugs later etc.

I know Nordic was using an electric TXV to get over the hump into multi stage DX and didn't really follow them do you know how or if they performed?

Nordic did not have great success with the two stage compressors. Some are still working, some had to be changed out due to burnouts.

I agree that there should be some code protocol regarding the mechanical spaces/basements where these units are installed.

The Earthlinked product look appealing, but like I have said, until I get performance specs and engineering data with a cut out of what they are using to control their refrigerants, I will be conservative.

Makes sense. I would be careful.

Industry in general doesn't like to publicize their failings (heat pump manufacturers included). I contemplated dropping Climatemaster last year when I had a problem with a 2 month old unit and without much data the rep told me to replace the TXV. This made it clear to me that they were aware of frequent problem with TXVs but told me about it only after I had several units on the ground (they since came out with the Re-Nu solution that fixes most systems).

I actually discussed changing brands privately with contributing contractors on another forum and was more or less persuaded that making a change did not insulate me from such things. The upshot is in water source systems I don't remember any fatal designs with 2 stage compressors but I am aware of a variety of fatal designs with DX systems (1 and 2 stage).

I often recall a comment made by a geo aquaintence of mine "The road to bankruptcy is paved with the bones of DX dealers" and I actually know one distributor that appears to be out of the business entirely (he used to contribute here). I'm also aware of DX success stories and more than one dealer such as yourself that installs them with confidence.

All is interesting to me as I have been very vocal in criticism of the DX manufacturers and the way they conduct their business. I have not, however, been particularly critical of the technology itself (or the dealers by and large). In fact I have suggested that we may all end up DX one day.

In our charity band we discuss risk/reward in song selection i.e. low risk/high reward: "Shout" (Isley Brothers) get close to the notes and tempo and eveyone loves it and says "wow we never hear that live" (and only three chords) vs high risk/low reward: "Desparado" gotta hit the notes gotta get the chords right and people may or may not remember it by the next set. In the context of DX I just wonder about risk v benefit for dealers and end consumers.

See ya on Linkedin sometime John,
j

I had an Earthlinked sales guy call me last week all excited about getting me on board with their new product, being unaware that I have lost serious money on the three Earthlinked jobs that I did a few years ago.

He said there were others dealers in Utah who are having great success with Earthlilnked systems. When I asked him who, he mentioned two who are now out of business, Clark being one on them.

I laughed out loud and said he was a typical salesman... all B.S. and no truth. That pretty much ended the conversation

I dont see 2 stage systems making any difference for DX. A sound pumping strategy and properly designed loops take all the wind out of DX sails. The potential rewards are false and the risk is very real.

I think application is one of the problems with DX. By that I mean their usefulness is not universal. I think the East and mid west seem to have conditions and soils that agree much better with shorter DX loops than the West.

I would agree Joe

I don't argue whether or not DX can work. Of course it can and does work. I agree that some locations are better than others. It's just that I take issue with salesmen and sales literature that promote DX as heads and shoulders above water source technology. They promote that there is an operating cost benefit that really does not exist. The fundamental problem with DX loops is that they extract heat at a greater rate than the ground can keep up with.

I agree with dude as well....I am just an agreeable guy

Geo dude I think many water source heat pumps extract heat faster than the ground can keep up with (aside from open loop). I also think literature for most products tends to embellish capabilities. So I'm not critical of DX for these things.
In fact it's hard to quickly sum up why I take issue with DX which is why my "trouble with DX blog" is about 3 pages at a 12 font.

Got the performance specs today, utterly confusing.

Even if I make sense of it all, I will probably stay away from the technology altogether.

I don't wish to be a beta tester.

There's the problem, it's one thing to try out a new one or two hundred dollar something but geo systems are not cheap. I know folks fantacize that all of us geo dealers make ten thousand bucks on every job, but having to eat a system or two would be a terrific burden on most any contractor I know.

For what it is worth, the manufacturer Maritime Geothermal "Nordic" DX line is no longer going to be manufactured.

Turns out that their margin was 3% of their entire business, and what with AHRI testing being what it is, they were having to spend in upwards of $50,000 a year in testing.

But Joe.AMI you are correct, a couple of failed systems can only lead you down the road to bankruptcy. I need to have performance testing data in hand before I even humor specifying these components into a design.

And as I hear of one manufacturer leaving the DX arena, another quickly takes its place.

http://www.nortek.com/news/nortek-global-hvac-launches-earthdirex/

That's a shame, I always felt that as a manufacturer of both, Nordic lent credibility to DX systems. The were also perhaps the longest line of DX in existence without out a name change.

Eeesh Nordyne in the DX business......not very impressive EER/COP if it is peak.