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  1. #14
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    Jul 2008
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    Poestenkill, NY
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    769
    Quote Originally Posted by griz7674 View Post
    I believe the water temps in the line were at 88 and 87 degree's which he said was a bit warmer then he wanted but not surprised given the system is not even 2 months old. He said that this number would drop as the system matured.

    Bob
    I don't see why it would drop as the system "matured" -sounds like a red harring.

    If the well field is not reverse return (which requires more pipe), you may have balancing issues in the wells - which is to say much or most of the flow is going through only a few wells. This really inhibites the overall performance of the well field as a heat exchanger. This will result is higher well temps in the summer and colder in the winter, reducing system efficiency on both ends.

    Another issue - how far are the wells from each other? 20' is sort of an industry standard, but may not have been used because the layout went from 5 to 11 wells. The closer they are together, the more linear feet of pipe you would need to do the same job.

    I would ask about both of the above if you're not sure... Especially since the delta t is only one degree.

    This all being said - 88 deg F is within normal operating limits -but if it continues to climb the rest of the summer, I would start to strongly suspect the well field as being deficient as I described. Again, know that as the source temp approaches the upper and lower limits, efficiency of the heat pump suffers.

  2. #15
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    Jul 2008
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    8
    What are the normal operating temps for the midwest (Illinois) for summer vs winter months? Also, is there way for me to check myself on the reverse return?

    Bob

  3. #16
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    Jul 2008
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    Poestenkill, NY
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    Quote Originally Posted by griz7674 View Post
    What are the normal operating temps for the midwest (Illinois) for summer vs winter months? Also, is there way for me to check myself on the reverse return?

    Bob
    It's not so much a regional thing, it's an equipment thing. GCHP's have upper and lower limits on the source water temp. 90 or 95 is usually a good cut-off for design purposes on the upper end. Temps above this won't shut the unit down or anything, it will just run less effieciently.

    Let me clarify. It will cool with source temps approaching 120 deg F (this depends on the specific equipment, but generally speaking), but the EER may be half of what it is with 80 deg F source water.

    What I am driving at here: If the well field is less than ideal the source water temps will fluctuate more. The linear feet of well is only one metric, others things to consider are: the space between wells, piping configuration (reverse return or not), ground conductivity, water movement, thermal diffusivity, and more. Since we have no power over the ground characteristics, the well needs to be designed properly.

    You will have to ask the installer about the reverse return and spacing between the wells. It is his buried secret!

    I don't mean to send you into a tizzy thinking the well field is all messed up. I'm giving you some info to be better informed about the system. The fact that the well field went from 5 wells to 11 makes me take notice because the cost went up for the installer, which results in shortcuts being taken.

    If you have one well-field that is reverse return piping, 11 wells 20 or 25' apart, and another well-field that is not reverse return, 11 wells spaced maybe 10' apart, both the same linear feet of well piping, the former will outperform the later 10 fold. A better performing well will have "steadier" temperatures.

    Make sence? I hope this isn't too much confusing info...
    Last edited by larobj63; 07-29-2008 at 05:00 PM.

  4. #17
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    Aug 2006
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    Dallas (Plano), TX
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    168
    Quote Originally Posted by griz7674 View Post
    it's good to know that I am not going crazy here but am actually using more power then what I should.

    ... you have one inch pipe at 600 feet (down and up) per hole with 8 holes total?

    I believe the water temps in the line were at 88 and 87 degree's which he said was a bit warmer then he wanted but not surprised given the system is not even 2 months old. He said that this number would drop as the system matured.
    Bob, put together some kind of KWH monitor, and during the day, run a test. Turn off your HVAC and everything not normally used - lights, ceiling fans, televisions, XBox360s, Wiis, cable tv set top boxes, etc. What's left will be refrigerators, security/fire monitoring equip, computers, communications equip, etc. Get average watts consumed, multiply it by 24, and now you've got your 'base load' in KWH. My 'base load,' at 1500 watts, or 36 KWH/day, says that we should consider using laptops and getting rid of one of our old refrigerators.

    I have 8 holes at 300' each. My pipe is 1" HDPE - down and back is 600'. My well field was designed at 1 hole per ton.

    I've learned that EWTs are very dependent on the borehole field's performance. 88° EWT is getting pretty close to 90°, where the GSHP's EER starts equalling the higher SEER conventional air-to-air HPs.

    I don't know how a borehole field can 'mature,' unless it has something to do with the thermal performance of the grount and earth as it settles back in closer to the pipe.

    I don't understand the thermodynamics of borehole fields. For example, for my well field, my EWT is quite variable these days, and even depends on the time of day as if it's influenced by outside temp. My chart of EWT for the past 20 hours is confusing to me, seeing EWT vary from 77 - 83° ( http://welserver.com/WEL0043/EnteringWaterTemps.gif)

    I wonder if you were to measure your EWT at 6 AM, if you'd get the same 87 - 88°?

    Looking at some of the other comments:

    My hole spacing is at least 20'. I don't know what 'reverse return' is or if I have it at my loop pipe manifold.

    Best regards,

    Bill

  5. #18
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    Aug 2006
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    Dallas (Plano), TX
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    Quote Originally Posted by griz7674 View Post
    I believe the water temps in the line were at 88 and 87 degrees ...
    Bob, when I responded above, I missed the signifance of your comment quoted above.

    If you meant to say that your LWT is 88° and your EWT is 87°, and you're confident that you understood this to indeed be the case, then I'd recommend you have the temperatures tested again.

    A 1° DeltaT doesn't make sense for a big, powerful Envision 5 ton unit. You'd have to have an incredibly high flow rate (GPM).

    My DeltaT for my 5 ton Envision averages about 5° (see http://welserver.com/WEL0043/DeltaT-...Exchangers.gif ). And my flow rate is 'off the chart' at 21 gpm (yielding about 51 KBTU/hr heat rejection capacity).

    If you do believe your 1° DeltaT is accurate, I can't imagine how you'd have much heat rejection capacity / cooling performance. And in this case, I'd get it checked again, along with your flow rate.

    Best regards,

    Bill

  6. #19
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    Jul 2008
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    8
    On the front bottom right of my waterfurnace, there are 2 "pipes", one right above the other, that the installed inserted a temp probe into. I believe the top one said 88 and the other said 87. I don't know if that helps explain where the temp readings were taken from. I do know that the water coming into my home has the copper pipe hot enough that I don't care to leave my hand on it. I would say it's in the 125 degree range if not hotter. So, if that is the indicator then I am from 88 degree's to well over 125 degree's. As you can see, I know nothing about hvac but I guarantee you I am learning daily!

    As for my well field, my line of wells run for a minimum of 20 foot, probably closer to 25. I would like to believe that the installer did not take any shortcuts as this one project literally took him from the middle of March to the first week in June! His drilling rig simply was not what he was promised.

    With regards to maturing, both the installer as well as what I've read online, a geothermal system takes time to run at peak performance. The dirt has to settle back into the holes and a whole host of other things. I was told that it could take up to 2 years before the system was truly running at optimal and predictable performance.

    Bob

  7. #20
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    Jul 2008
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    Poestenkill, NY
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    Quote Originally Posted by griz7674 View Post
    On the front bottom right of my waterfurnace, there are 2 "pipes", one right above the other, that the installed inserted a temp probe into. I believe the top one said 88 and the other said 87. I don't know if that helps explain where the temp readings were taken from. I do know that the water coming into my home has the copper pipe hot enough that I don't care to leave my hand on it. I would say it's in the 125 degree range if not hotter. So, if that is the indicator then I am from 88 degree's to well over 125 degree's. As you can see, I know nothing about hvac but I guarantee you I am learning daily!

    As for my well field, my line of wells run for a minimum of 20 foot, probably closer to 25. I would like to believe that the installer did not take any shortcuts as this one project literally took him from the middle of March to the first week in June! His drilling rig simply was not what he was promised.

    With regards to maturing, both the installer as well as what I've read online, a geothermal system takes time to run at peak performance. The dirt has to settle back into the holes and a whole host of other things. I was told that it could take up to 2 years before the system was truly running at optimal and predictable performance.

    Bob
    Hmmmmm...

    A few basics:

    Your heat pump has a source water side and a load side (or building side).

    Source side: The water coming in and out of your house is going to and returning from the well field. As noted, a 1 deg delta t is either wrong or alerting a major problem (is this when the unit is running?!).

    Load side: The load side supplies and returns to and from a hot water coil in your furnace (I assume at this point we are talking a water to water heat pump? -only because you mention 125 deg water???).

    What do you mean your line of wells "run for a minimum of 20 foot"? 20 feet between each well, all around?

    The settling and such you speak of will not result in overtly in-efficient system performance for up to 2 years...

    I'm part ogf the problem here, maybe there is nothing wrong with the set-up, and you just have a high base load electricity use.

  8. #21
    Join Date
    May 2002
    Location
    arkansas
    Posts
    27
    the 125 degree copper line you speak of is the dhw hot water line which preheats your water before it goes to the water heater. you need to look into the 1 degree delta T if its correct then theres a problem. oh and the spot where the installer checked the temps are called PT plugs.

  9. #22
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    Jul 2008
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    Poestenkill, NY
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    Quote Originally Posted by hangingduc View Post
    the 125 degree copper line you speak of is the dhw hot water line which preheats your water before it goes to the water heater. you need to look into the 1 degree delta T if its correct then theres a problem. oh and the spot where the installer checked the temps are called PT plugs.
    Good call. De-superheater?

  10. #23
    Join Date
    Aug 2006
    Location
    Dallas (Plano), TX
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    Quote Originally Posted by griz7674 View Post
    On the front bottom right of my waterfurnace, there are 2 "pipes", one right above the other, that the installed inserted a temp probe into. I believe the top one said 88 and the other said 87.

    ... I do know that the water coming into my home has the copper pipe hot enough that I don't care to leave my hand on it. I would say it's in the 125 degree range if not hotter.
    Bob, since you and I have the same Envision model, here's a picture similar to what I think you have:




    Bottom two pipes go to the loop field - these are the 2 pipes that have the connector (PT Port) that a temp probe and pressure probe can be inserted into. My EWT and LWT are 83° and 87° at the moment.

    Upper two pipes go to DSH loop - temp of either of these pipes could be upwards of 125°, depending upon what kind of tank you're connected to.

    Best regards,

    Bill

  11. #24
    Join Date
    Nov 2007
    Posts
    86

    Get another installer!

    I’m sorry to have to say this, but your installer sounds like an idiot! Get another installer (ISGHPA Accredited) in there that knows what he’s doing and have him measure the systems actual COP, among (many) other things. You may also need a lawyer…

    SR

  12. #25
    Join Date
    Jul 2008
    Posts
    8
    I do plan on paying to have another installer come check his work. It will be interesting to see. As part of the install, he had to cover up my attic access in order to get the entire unit where I wanted it. So, I just cut a new access and decided to double check the insulation instead of taking the contractors (the one's who first bid the project) and the installers word for it. Here is what I found. I have insulation that equals a total of 6 inches. It is kraft paper insulation without the paper. From what I have read and been told, I need to be around 18 total inches. So, the phone calls have been made to get more put in. My buddy insists on kraft paper insulation vs spray in. Thoughts there?

    Bill, you and I do have the exact same unit. I have taken 2 pictures of my install. When checking it right now, my copper pipes were both very cold to the touch. My geo has been off for awhile as I set the temp a bit higher about an hour ago. Should those pipes ever be cold or do they only get warm when hot water is being called for?

    Bob


  13. #26
    Join Date
    Aug 2006
    Location
    Dallas (Plano), TX
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    168
    Bob, in general, the DeSuperHeater option on your GSHP unit is only operational (i.e., heats water) when the your GSHP unit is running - i.e., water loop pump(s), compressor and blower.

    The temp of those copper pipes, near the GSHP, will be little different than ambient temp after some time has expired from when the GSHP was running.

    Best regards,

    Bill

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