Pennsylvania Higher than expected electric use

Discussion in 'Maintenance and Troubleshooting' started by AndrewL, Jan 22, 2015.

  1. AndrewL

    AndrewL Member

    Here is the HVAC Load calculation from my contractor.

    Attached Files:

  2. AndrewL

    AndrewL Member

    Here are details on Geo loops:

    Horizontal loops (3 ea)
    • They are made of four 200’ long twister pipes hooked up in series. The twisters themselves are laid out sequentially, like 1,2,3,1,2,3,1,2,3,1,2,3 See this image: Horiz Layout.png
    • Twisters are connected to each other and to the pumps using 1-1/2” diameter HDPE. Approximately 400’ of 1-1/2” is used in each loop. No grout was used in horizontal loops.
    Vertical loop (1 ea)
    • Four Twisters are installed in two 125’ bores and two 150’ bores. The twister in the bore is grouted. The remaining length of twister was looped around horizontally (and not grouted).
    Each Twister is made up of 4 separate loops of ¾” diameter HDPE ; each twister package is approx. 5 ½” diameter. So total length of ¾” pipe in each twister is 1600’
  3. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Twister pipes are new terminology for me. Anybody have more info?
  4. AndrewL

    AndrewL Member

  5. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

  6. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The temperatures and the difference between incoming and outgoing water (delta T) you posted suggests that your loop field is performing absolutely fine, for both flow requirements and heat capacity.
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I hate dry wall in basements. It makes it very difficult to change things.

    The insulation below the pex and plate needs a higher R-value the the sub-flooring and finish flooring above it. If that is not the case, it is still a radiant ceiling. Heat water and air take the easy way.

    Do you have any data Andrew on what was installed?
    Last edited: Jan 31, 2015
  8. AndrewL

    AndrewL Member

    R-19, paper up, and they kept space between the paper and subfloor.
  9. AndrewL

    AndrewL Member

    Here are some recent loop temps taken with a thermometer at the test ports on the HPs. (#2 not running)

    #1 35.7 / 40.4
    #3. 26.1 / 30.6
    #4. 29.0 / 33.8

    Outside temp 15F
  10. dgbair

    dgbair Just a hobby Forum Leader

    I bet your outside loop picture isn't quite correct... those sets of 4 are most likely hooked up in parallel, otherwise your head pressure would be way too high for the pumps. (1600' in series would be around 70' of head)
    As Doc said, your loops seems to be doing fine; and based in the info you provided (and my somewhat limited waterflow math skills) it seems like the 8 loop+4 HP pumps are size just about right.
    I'm about 2 hr north/west of you... 2F here this morning, my EWT is 32.5 LWT 27.6. (unit has been running since 3:45AM)

    How are your run times since making the adjustments?
    How do you have the units staged now? (guessing that unit #2 isn't a primary unit anymore)
    Have you taken a look at the on time of the steam humidifiers?

    Inside zones: Do you have all the details on the install? - Pex diameter/length of each zone. (I'm thinking that is what Mark is asking for)
    Palace GeoThermal likes this.
  11. dgbair

    dgbair Just a hobby Forum Leader

    Any chance of making that area semi-conditioned?
  12. AndrewL

    AndrewL Member

    I'm nearly certain that the horizontal loops are in series, but I will double check.
    Run times are better, but the load is not well balanced among the HPs. Is there a control that I can add to handle it? (Tekmar 284 The 406 is set to Rotate and HP2 Delay is 20 Min. It seems that it's not rotating, just using HP3 first and then HP1. Consequently, HP4 gets more use and HP2 hardly any.
    Only two of the three Steam Humidifiers are operational, and they seem to run non-stop. I think this isn't a whole lot of energy in comparison, though.

    I don't have any lengths on the inside zones. Pex is 1/2" under the floor and 1" to the manifolds.

    I may be able to make the space where the two attic Air Handlers are semi-conditioned.
  13. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    The HBX Eco-1000 can deal with 14 heat pumps (with the EXP 0100s).
  14. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    The magic length not to exceed when using 1/2" pex in radiant panels is 300' on each manifold loop. When calculating head loss one only needs to count one loop.

    With 1" feeds, and a 20* delta T, the maximum BTUH is 71,000.

    R-19 should turn the radiant ceiling into a radiant floor depending on floor covering. The R-value below the pipe and plates wants to be greater than the R-value above them.

  15. AndrewL

    AndrewL Member

  16. AndrewL

    AndrewL Member

    Yes, the loops on the individual Twisters (sets of 4 3/4" tubes) are hooked up in parallel, but the four 200' sections are in series.
  17. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    Tekmar is Tekmar. HBX is HBX. They are competitors. Both out of BC, CA. They might talk to each other but not in my life time. I speak Tekmar and am learning HBX. I have a 406 in service here in Ohio.

    Where are you in the learning curve on this? Has your power bill gone down? Are you still comfortable?

    I am falling in line with Chris and Dewayne, that you issue is the control system and not so much in the physical plant. Your graphs I let go in one eye and out the other except for the spikes and the frequency of the repeated spikes. Not a good way to run a railroad or a four unit geo system. Low temperature lift and steady state operation is the best result for fuel costs and comfort.

    Yeah! Stephanie, the great, just returned with enough pre-storm Linus provisions to last until Tuesday here in Cleveland. Other than a few loop head losses and materials lists I can type with you guys for three days. Sorry Tamar and any other female folks here.

    I have seen graphs, that I have not looked at deep enough for them to be meaningful. It is something I can learn, but like looking at my own EKG, the line is not flat. I saw the staple-up photos, and that looks to be good workmanship on the installation, if what they told you about the insulation added is true and installed well. My next question is what is the R-value of the material above the pipes and plates on a square foot basis. I can send you an RPA R-value chapter on floor covering.

    I think your home has a few more bells and whistles than it needs, but that is not to say they can not be controlled to your better advantage. Help me understand the piping.

    Each geo unit has its own loop system?

    All systems are water 2 water?

    They all feed that little bitty 80 gal tank?

    All of the loads pull off the tank?

    You are using a 406, what else do you have by Tekmar?

    Do you know what Tekmar plumbing diagram they fashioned the system after? From the 406 design manual.

    Where is your installing personage in all of this?

    Geothermal design and control engineering is not for the faint of heart, but what does an old retired hippy with a degree in journalism and history know about engineering and heat transfer, much less plumbing.

    I think, Andrew, you bought what you wanted, and I think it will make you happy. If you can get someone there that knows the piping and the control system.

    We go up to 600 miles in any direction from Tower City. Let me know if I can help.

  18. AndrewL

    AndrewL Member

    Power consumption isn't noticeably improved. If I plot kWH / Heating Degree and add a trend line, it is decreasing, but I don't know how valid this measure is. The house is still comfortable.


    Sub floor is 3/4 plywood with either oak, carpet or marble on top of that.
    Yes, each Geo HP has its own loop.
    All systems are water to water.
    Yes, all feed one 80-gallon storage tank
    All loads pull off of that tank.
    Thermostats are Tekmar. In addition to the 406 there are three 314s and one 483.
    In the 406_d_02.pdf,i dont see any models that are all that close.
    Install / design company is trying to wash hands of the project, so I'm basically on my own.

    So in a nutshell, Mark, what do you recommend?


    Last edited: Jan 31, 2015
  19. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    The issue is there is no nut shell for me at this time, yet. I know the control system. You are not happy.

    Tekmar goes out of its way to make drawings for the logic they program into their controls. Follow the drawings and one lives happily ever after. Do you have a copy of the 406D manual? I know what 317 wiring moduals are I will go look up the 483 modual.

    I think what you have can do what you want at a lower electric bill.

    I think you need more tank(s).

    What is the number on the stats? Do they communicate with the rest of the system?

    I can fix this system.

  20. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Can you just tell us your load? I opened your attachment and nothing was there.

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