The trouble with DX..........

Discussion in 'General Discussions' started by AMI Contracting, Mar 11, 2012.

  1. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I have continued to gently (uncommon for me) voice my DX concerns but feel obliged to sum them up given recent rebirth of the topic.

    Want a DX system? Ask yourself these questions:

    1) Do I want a system that is not recognized by the International Code Council?

    It is true, in Michigan for instance if you install a DX system the code requires a hydrostatic test of loop of hands, who wants to run water in a refrigerant circuit hundreds of feet long? How do you get it all out to avoid damage to the compressor?

    2) Do I want a system in my home that (often) the same code requires an industrial type machinery room for?

    Also true. Though the International Mechanical and Residential Codes apparently haven't heard of Direct Exchange Heat Pumps, they do identify that once over X lbs/ft3 of X refrigerant, one must have a machinery room with ventilation, refrigerant leak alarm etc. Let's say it again, the quantity of refrigerant in your DX system if leaked, could be injurious to the occupants of your home- therefore industrial measures (and related expenses are required).

    3) Do I want a system that eliminates an inexpensive circulator pump, simultaneously increasing the workload of an expensive compressor?

    While seldom mentioned, don't you think adding (sometimes) 1,000 extra feet to a refrigeration circuit might tax a compressor a little more?

    4) Do you want to put geo loops in the yard that very seldom corrode (if proper protocols are followed) or the ones that never do?

    I grow weary of water source guys hype of loop corrosion or refrigerant leaks in the ground. A Good DX installer will mitigate the possibility to almost nothing. That said, HDPE fears only impact and sunlight.

    5) Do you want a system that is 3% of the market, or 97%?

    Seriously if you were buying a car- one to take you to work everyday, are you going to get the one that often costs more, has a smaller dealer/tech/part network just because the salesman says you might save $90 a year in gas (based on laboratory tests not actual driving)?

    6) Do you want a system where most manufacturers, license holders etc have not held the product line for 10 + years?

    Go ahead check some domain registrations etc. and please don't bring up the sale of FHP to Bosch, I don't think Bosch is in the same catagory as XYZ DX, LLC.

    7) Do you want a system where most dealer/installers have spent less than 5 years with the product?

    8) Do you want a system that attracts more new guys since they don't have to buy new tools?

    Watersource manufacturers aren't particularly better at vetting new dealers, but extra tools and less finicky installations suggest greater financial security and less opportunity for mishap on installation.

    9) Do you want a system with 5 times the refrigerant in it?

    Things made by people and installed by people do fail. If you get a leak on a your system do you want the one that has less or more- like maybe $800 more to leak out?

    10) Do you want the system that tears up more of your lawn?

    While DX boasts of smaller foot prints, what they mean is less pipe. Sometimes this is more holes however or longer trenches etc.

    11) Do you want the system with less loopfield flexibility?

    DX loopfields are refrigeration circuits that ave a prescribed length and pitch- coloring outside those lines may interfere with compressor's oil recovery harming the equipment. Water loops can follow the grade (saving excavation on hilly lots) or be increased where dry soil is present.

    Do you have DX in your home now? Do not despair.

    Systems in my AO have been up and running more than 20 years.

    Efficiency while ultimately hindered by ground thermoconductivity is still quite good.

    Everything that has refrigerant in your home is potentially Injurious to the occupants. That a DX system has more suggests no greater risk of leak occurance, and injury is unlikely.

    Greater sales today will hopefully keep some of these guys around for parts etc.

    Who sells DX? With all this in mind why would anyone want to sell DX equipment? There are essentially 3 types of companies:

    A) Tax credit band wagon guy-

    Often low bank prefering system with less business start-up costs (i.e. fusion tools, flush carts etc.)

    B) Marketing minded guy-

    "everyone is selling those systems for X price, if I'm the only one selling this system I can charge a more premium price."

    C) Old geo guy trying out new technology, perhaps thinking of a distributorship opportunity down the road.

    Or it may be some combination of the 3. My decision after training in 2 different systems (kinda a combination B and C guy)? I made friends in that industry in MN that I trust and would like to support but for now I must wait and see. I have not decided not to ever sell DX.
    I had to ask myself "why is the biggest dealer of the biggest distributor of X brand, dropping the product in favor of water source?....and why did that same distributor just take on a water source product?" Geo systems are fairly expensive, eating a few lemons can really hurt a small shop.

    About your DX dealer you will have to ask yourself:
    "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.

    Then of the manufacturer you have to ask why an organization as big as the International Code Council is not worth approaching to get the equipment recognized and maybe the refrigerant detector waived by exception or at least a reduction of measures required for compliance.

    All that said, the best geo heat pump is still "whatever is sold by the best dealer in your town." This does not rule out DX.

    There are always exceptions.

    I welcome rebuttal from a DX manufacturer.

    I think I may contact the ICC myself to see if they have been approached and if there is something new in the pipe line.

    Joe Hardin
    Last edited: Mar 16, 2012
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Thanx for this post. It is the best summary and overview that I have seen in one place. A word of warning, when you ask th hard questions, you get hard replies:)
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I would add that there are large claims being made for higher efficiency of DX by many manufactures or installers, but the data where these claims supposedly come from is no where to be found. Not even a single case report.
  4. GCI

    GCI Member


    This is awesome. Well put sir.
  5. GCI

    GCI Member

  6. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Doc I think higher efficiency would be easier to achieve with DX in a given time and space but quickly mitigated by surrounding soil TC. Water source manufacturers certainly aren't strangers to elevated performance boasts.

    People I respect are in the industry however (one I miss around here....anyone heard from Clark?) and I spend little time splitting hairs on peak efficiency. I'm interested in averages and cost effectiveness for my customers. With my local electric rates ROIs are impacted more by lower install cost not lowest op cost.
    I still install single stage equipment after all:eek:

    I mentioned elsewhere that CSST found it's way into our code books in less than a decade.
    I am awaiting further conversation with ICC and will hopefully have more to share.

    Thanks for the kind words Ryan, Dewayne, Eric, every time we find ourselves in the debate I find myself hesitating to sum up all my reservations at once (as it is folks probably think I'm paid by the word around here).:D
  7. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Would not have predicted verticals had that big a market share Ryan, are you sure that survey wasn't completed exclusively by well drillers?;)
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I refer to real world performance, running the system for a month, or even better for a year. The main reason why I have trouble following the efficiency argument is the fact that Dx is extracting the same amount of heat from a smaller volume of ground. After time, ground temps drop fast and kill efficiency.
  9. GCI

    GCI Member

    I would say that the number of people who responded to this survey so far isn't large enough to be considered a representative sample. It could very easily be skewed by a higher number of well drillers completing it relative to the other trades that were surveyed.
  10. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I am trying to focus on issues exclusive to DX. Nobody sustains peak efficiencies yet all brag that they are highest.....take excerpts from their own brochures.

    Water Furnace:

    WaterFurnace Envision systems are rated number one in energy
    efficiency because they can deliver an astounding five units of energy for every unit of electrical
    energy used. Compare that to even the best ordinary system that delivers less than one unit
    of energy for every unit it consumes. That translates into an efficiency rating of 500 percent,
    compared to the most efficient
    gas furnace, which rates only

    94 percent."

    So does WF sustain 5 COP? Even if they don't they are rated #1 in efficiency.


    The Tranquility Series provides you the highest energy
    efficiency of any space conditioning system available.
    Efficiency equals savings, and geothermal heat pump systems
    substantially reduce operating costs over even the most​
    effi cient traditional systems.

    Oh... so Climatemaster is the highest efficiency no matter the conditions.


    "ENERGY STAR® Most Efficient
    Bosch TA Series Geothermal Heat Pump has been awarded ENERGY STAR® ME -the only complete geothermal line in the industry to meet such criteria."

    So wait a minute, Bosch is the most efficient and Energy Star says so.......

    How can everybody be "the most efficient"?

    I can not indict DX for exaggerated claims without indicting the entire geo industry.

    I also expect DX probably is the most efficient for the first few minutes of operation just as sure as WF gets a 5 COP sometimes.......

    Of all the criticisms I have about DX, this really does not rank near the top ten.

    Rgausman likes this.
  11. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I din't read all the way through, but does it distinguish between resi and commercial geo? I find it hard to believe DX is even close to resi open loop systems.
  12. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I found it hard to believe that only 2% were open loop??? The sample group may be in alot of states where it is not allowed??
  13. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    FYI still waiting on ICC.....maybe I shouldn't have said I wished to post their replies.
    Perhaps I should write Earthlinked for their opinion.
  14. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    CC my Email to a DX manufacturer-

    To Whom it may concern,
    I have trained in 2 different DX products and consider yours the front runner but have not pulled the trigger based on reservations I have itemized on blogs at both geoforums and geoexchangeforums.
    I sell 100s of thousands in geo each year and am confused by the DX industry as a whole in not legitimizing the product.
    Among the most pressing of my questions is why the industry has not found it necessary to present the product for recognition with the ICC. How DX manufacturers intend to compete when ICC inspectors enforce the requirement by current code that the product be placed in an industrial type machinery room due to lbs/refrigerent/cuft. How ICC inspectors not require hydrostatic tests of ground loops etc.
    Please respond on the forums or privately (though I will share your replies).
    Joe Hardin
    AMI Contracting
    Michigan Mechanical Contractor
    Michigan Mechanical Inspector
    Michigan Boiler Installer
    IGSHPA Certified Installer
  15. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I hope they notice.
  16. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    yeah well my email to them (and the code council) apparently arent worthy of reply.
  17. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    The truth is out there

    ^^^^^sends more beers, will bring more steaks.
  18. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    ...and fine steaks they were!
    Note from ICC tells me the engineer assigned my question has been reminded of the question. DX manufacturer yet to respond (didn't expect anything, not sure how they can win unless its to tell us they are meeting with ICC).
    Im suprised DX flag waiver on another site hasn't chimed in.
  19. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Email to another DX manufacturer. FWIW I spoke to the president of this company a year or two back about DX among other things. As a manufacturer of both technologies (water source and DX), this outfit seems to add legitimacy to DX industry.
    If you go to the DX section of the Nordic website you will see that they seem to stand alone in manufacturing DX package systems and they do a good job of summing up and solving previous shortcomings. They also do a good job of touting all the alleged DX advantages that I (and Doc especially) bristle at.
    I have reffered them to our questions and hope for a reply.

    I've spoken with you folks before and hoped since you manufacturer both DX and water source equipment you could share in a dialogue. DX manufacturers in the states don't seem to want to.
    Can you tell me if DX systems are recognized by any code in Canada or are you aware of a movement afoot to get it recognized by codes in the states.

    Here is the blog in which specific concerns are voiced about DX.

    (link deleted)

    I'm a fan of the technoloy but find the absence of clarity in the codes a deal breaker.

    Joe Hardin
    AMI Contracting
  20. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Sorry guys- just reluctant to let this go.

    FWIW- ICC responded this week.
    I was referred to the latest "Green Code" for testing loop efficiency. I replied that my concern was with the "hydrostatic" pressure test required by the IRC and was told they'd get back to me................72 hours ago.

    Still no response from DX manufacturers.....or installers.

    Not trying to bust anyones chops but for cryin' out loud, does no one care enough about the product to make it mainstream?

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