Earthlinked DX, conversation with rep

[gbig2]

I filled out their dealer locator form and someone contacted me just now. I've had 3 watersource guys out to the house to give estimate. I'm debating about having a DX guy come out also. It seems people are pretty negative on the DX. Here's some things he said:
1. Even though the posted docs on their COP % show 3.6 or lower, their actual COPs are five or higher. He says my ground temp is 51 degrees so he says I can get a 5 COP at that temp. He says DX can be %25 more efficient, less pumps, etc. He says their COPs are hurt by the criteria used to test COPs, that the testing is more favorable to watersource since the testing agency or company requires the water to be 32 degrees, which is why DX shows COPs of 3.6 instead of 4.6.
2. Warranty on loop is 20 years. I believe watersource loops are 50 years? He said they haven't had a loop leak since 1980. I said why not warranty it to 50 years then like watersource? He didn't have a very good answer to that.

I'm debating if I should even have someone come out. The 20 year loop warranty is a deal breaker, right? Is what he says about COP's correct?

Thanks
Greg

[Mark Custis]

of AMI Contracting fame is playing email tag and ignore with the DX folks you might want to look up his thread. They will not last in my AO of Ohio unless the are coating the coils in pex or HDPE.

I can not address the testing issue. I did fight long and hard about tax credits for water to water units.

Mark

[Looby]

He says their COPs are hurt by the criteria used to test COPs, that the testing is more
favorable to watersource since the testing agency or company requires the water to be
32 degrees, which is why DX shows COPs of 3.6 instead of 4.6.

A steaming pile of Meadow McMuffins, because:

1) The 32 degree crap is pure technobabble. DX doesn't have anything to do with water.

2) The 32 degree requirement for water-source closed-loops is a highly UNFAVORABLE
and very conservative test condition. It doesn't inflate COPs -- it deflates them to yield
pessimistic, near-worst-case ratings.

.

[Palace GeoThermal]

He says my ground temp is 51 degrees so he says I can get a 5 COP at that temp.

Thanks
Greg

As soon as you start taking heat out of the ground, the temp will drop and be down to 30° or less by the end of the heating season.

[AMI Contracting]

Fact is 32* soil around loops hurts all systems (or I should say drops their COP), so by the same criteria water source systems would have a higher COP with higher surrounding temperatures. Further Earthlinked training encourages heavy loading to allow greater down time during ground freeze as the soil moves heat more slowly than their loops. This is not a quote but paraphrased from the comments of the Earthlinked distributor for my area who went on to say the only failed loops he'd found were had radial cuts from ground freeze caused by poor sizing.

I also know of a system in my area that has been running since the '80s. I agree that properly installed loops will not fail any time soon. Properly installed means (among other things) avoiding soil such as Mark sees in his AO. That said not only have there been loop failures since 1980, but Earthlinked is a 5 year old product name, previously ECR, and prior to that I'm reaching, but American Geothermal or US geothermal or..... it escapes me. The product bares resemblence to the original, suggestion that it is the same manufacturer is less than candid.

DX dealers often feel picked upon by water-source guys, and I agree that in some instances both sides deal more in emotional propaganda than rational debate. I can tell you a respected manufacturer in Canada, however, offers both products (DX and water source) which suggests they think that both are viable technologies.

You only need to drop about 5 titles in "General geothermal heat pump discussions" to read my reservations on DX. There is little comment on the efficiency issue as I think all manufacturers exaggerate theirs. In fact I mention that virtually everyone claims rights to the crown of most efficient. The reality is operating cost differences regardless of what you buy will likely be less than $100/yr difference at 10 cents/kwh if you employ a competant installer.

The most important questions you can ask are the ones I have there.
First determine if you are governed by the ICC. If so.....

"is he ignorant of the code- following the code- subject to a different code or ignoring the code?" and "why is the aggravation of selling the least popular product worth it to him". There can be very good answers to the questions, but you won't know until you ask.

I personally do not offer DX products at this time but continue to watch with interest to see if they resolve my concerns.

I would invite the individual offering DX to you to join us here for a healthy debate.

joe

[docjenser]

Said it before saying it again. The amount of heat you need to extract out of the ground is the same with either system, the DX now has to do it with much lesser amount of pipe and pipe surface area.
That means that the ground cannot keep up in transferring enough heat into the pipe. In order to work at all, now the refrigerant has to get much colder to increase the delta T between ground and pipe, resulting in much higher refrigerant pressures and less efficiency. I would argue that the ground around the loops drops actually way below 32F.The test conditions do not account for that reality and actually favor DX. The published COP actually paints a nice picture than the much colder sub 32F ground temps will render in the installed system.