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decafdrinker
Basic Member
Posts:420
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| 23 Nov 2010 09:49 AM |
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The problem is going to be getting it to stay in Stage 1 for longer than 10 minutes right now. If I jack up the temp too much, it goes into stage 2, otherwise, it get's satisfied in stage 1 in fewer than 10 minutes usually. I almost need it to be colder...or physically disconnect the stage 2 wire from the thermostat and then turn the system up. |
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docjenser
Veteran Member
Posts:1400
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| 23 Nov 2010 11:02 AM |
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Posted By stuart.wyss on 23 Nov 2010 09:49 AM
The problem is going to be getting it to stay in Stage 1 for longer than 10 minutes right now. If I jack up the temp too much, it goes into stage 2, otherwise, it get's satisfied in stage 1 in fewer than 10 minutes usually. I almost need it to be colder...or physically disconnect the stage 2 wire from the thermostat and then turn the system up.
That always seems to be the problem with those damned geothermal units, they heat things up too well! |
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| www.buffalogeothermalheating.com |
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geome
Advanced Member
Posts:987
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| 23 Nov 2010 11:51 AM |
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You could try temporarily setting the thermostat to a 1-stage system in the installer setup. Remember to switch it back! |
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| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
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decafdrinker
Basic Member
Posts:420
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| 23 Nov 2010 03:58 PM |
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Ok. here's what I did today.
Indoor temp 71. Thermostat set to stage 1 only, system ran for approximately 30 minutes in stage 1. House temp got to 72.
Flow gauges indicated 4 gpm per loop, or 16 gpm through the system.
DAT sensor reading (sensor in main supply plenum) 95 F
Assumed return air temp 72 F Delta of air temp 23 F
Manifold temps: 52.7 F and 45 F, Delta of 7.7 F
DSH temps: 93.7 F and 108.1 F, Delta of about 14 F across DSH coil.
Google Powermeter indicated that during the system run, my power usage went form 371 watts to 2.91 Kw. At the end of the test, power use dropped back down to 371 watts. The test lasted 30 minutes.
I also found out some interesting info about my installation. My installer claims I have two 300-foot boreholes with 2 loops in each borehole. The driller agrees that he drilled two 270-foot deep boreholes. However, the supply house that shipped the material to me says the loop material that was ordered was only 150 feet long (300 round trip). Is 150 feet per ton ok? Would that explain the aux heat usage last winter? Am I screwed? Should I start a different thread?
Would that also explain why 1 loop pump might be sufficiently pumping 3 gpm/loop? Less pipe to pump it through?
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joe.ami
Veteran Member
Posts:4377
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| 23 Nov 2010 06:54 PM |
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Not sure there is a problem to begin with.
In our area 150'/ton is common.
Make sure you don't begin to threaten warranties with experiments.
Joe |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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decafdrinker
Basic Member
Posts:420
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| 23 Nov 2010 07:42 PM |
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Yeah, especially any warranties with the original contractor! I'm gonna run some ideas by the new contractor tomorrow. |
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docjenser
Veteran Member
Posts:1400
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| 24 Nov 2010 02:01 AM |
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Posted By stuart.wyss on 23 Nov 2010 03:58 PM
Is 150 feet per ton ok? Would that explain the aux heat usage last winter? Am I screwed? Should I start a different thread?
Would that also explain why 1 loop pump might be sufficiently pumping 3 gpm/loop? Less pipe to pump it through?
That would put a different twist on it. In my area,150ft/ton is fine, but not when 2 loops are in one borehole. If I remember correctly, that does not even add 20% loop performance versus 1 loop per borehole. Check your facts, and check your contract what was promised. Get it in writing what is supposed to be installed, may be as an email. Next thing is that you want to measure loop performance. May be you are in an area where that kind of loop design supports a 4 ton heatpump (dense rock, great grout, spacers?, much water. So document EWT through the heating season, probably a WEL is something you could need. Yes, given this twist, a new thread would be appropriate.
PS: one thing you could do is drain the system out and measure the amount of fluid in there. With 1200 ft of pipe, you should have 27.5 gallons in the outside loopfield. I assume you have a non-pressurized flowcenter, since you header is inside. Or have your contractor do it to prove his point. If he is correct, you could pay him for it, if not, it should be on him. May be his hesitation will give you a hint. If a customer would ever accuse me of such thing, I would be there the very next day, doing this exercise with him. |
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decafdrinker
Basic Member
Posts:420
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| 24 Nov 2010 06:46 AM |
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The contract doesn't specify what depth...just says 2 boreholes. And communication between myself and the original installer have broken down. |
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engineer
Veteran Member
Posts:2749
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| 24 Nov 2010 08:07 AM |
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How would one drain a U-tube?
Is it possible the tube supply house made two shipments but only came up with records for one?
Do you have EWT data from last winter?
I'd like to see a new thread on this issue so we can start from scratch |
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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Palace Geothermal
Veteran Member
Posts:1609
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| 24 Nov 2010 08:47 AM |
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Posted By engineer on 24 Nov 2010 08:07 AM
How would one drain a U-tube?
I was wondering the same thing. Was your geo system functional last winter? If so, how did it perform? |
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Dewayne Dean
<br>www.PalaceGeothermal.com<br>Why settle for 90% when you can have 400%<br>We heat and cool with dirt!<br>visit- http://welserver.com/WEL0114/- to see my system |
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decafdrinker
Basic Member
Posts:420
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| 24 Nov 2010 09:04 AM |
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**********************************************************************
I'm going to let this thread continue to be about 'ideal' gpm flow rates, and start a new thread about my install.
I'll call it 'Boreholes don't add up"
********************************************************************** |
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docjenser
Veteran Member
Posts:1400
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| 24 Nov 2010 09:46 AM |
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Posted By engineer on 24 Nov 2010 08:07 AM
How would one drain a U-tube?
Is it possible the tube supply house made two shipments but only came up with records for one?
Do you have EWT data from last winter?
I'd like to see a new thread on this issue so we can start from scratch
We blow pressurized air in. May be "draining" is not the correct word... |
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engineer
Veteran Member
Posts:2749
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| 24 Nov 2010 11:25 PM |
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I thought about that, but wondered if you can get enough air at high enough pressure into the tube to be certain of entraining all the water. I would think the compressor needed to do that would come on a trailer and use quite a bit of Diesel fuel
I also thought about dying replacement water and waiting until that color appeared out the other end...with a long skinny tube there wouldn't be much mixing at the new / old interface.
Both of the foregoing thoughts are just that - not based in any experience. |
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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docjenser
Veteran Member
Posts:1400
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| 24 Nov 2010 11:57 PM |
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Posted By engineer on 24 Nov 2010 11:25 PM
I thought about that, but wondered if you can get enough air at high enough pressure into the tube to be certain of entraining all the water. I would think the compressor needed to do that would come on a trailer and use quite a bit of Diesel fuel
Not if you have headered inside, have 0.75 pipe and can isolate each circuit.It actually works pretty well. |
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| www.buffalogeothermalheating.com |
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decafdrinker
Basic Member
Posts:420
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| 06 Dec 2010 10:55 AM |
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Well, I disconnected 1 of the 2 circulator pumps in the Flow Center for the weekend. Unit had no trouble maintaining temperature.
Delta T across the coil was about 7 degrees.
Air delta was 25 degrees
Pressure drop was about 4, which at EWT indicated a flow of about 10-11 gpm total. Gauges show a total of 12 gpm. I'm guessing measuring flow by pressure is more accurate? Or is it really 6 of 1, half-dozen of the other? |
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TechGromit
Advanced Member
Posts:634
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| 06 Dec 2010 12:39 PM |
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Posted By docjenser on 03 Nov 2010 02:09 PM
I do not see any reason for reducing GPM manually, all the manufactures data shows that the heat extraction (heating) and the efficiency increase with the increased source flow.
I can, if the system requires 9 GPM for optimal efficiency, why pump 20 GPM though it when the Cost / Benefit ratio is minimal. While a higher source flow may be beneficial, I doubt it makes up for the increased pump load. For my open loop system, I have it set to 9 GPM, according to the Water furance documentation I have, that's the ideal setting for my system. |
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Looby
Basic Member
Posts:401
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| 06 Dec 2010 10:29 PM |
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Posted By TechGromit on 06 Dec 2010 12:39 PM
While a higher source flow may be beneficial, I doubt it makes up
for the increased pump load.
Most closed loop systems use small fractional horsepower pumps
such as Grundfos UP26-99. In this case, pumping power is mainly
dependent on the number of pumps. Regardless of GPM or delta-P,
each UP26-99 consumes about 245 watts. Period.
Throttling down decreases GPM but increases delta-P across the
pump -- and power consumption remains essentially unchanged.
(Actually, wattage might either increase or decrease (slightly!) --
depending on where you are on the pump's efficiency curve.)
power = (flow x head)/efficiency
...not just a good idea, IT'S THE LAW!
Looby |
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| One measurement is worth a thousand expert opinions. |
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docjenser
Veteran Member
Posts:1400
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| 06 Dec 2010 11:43 PM |
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Posted By TechGromit on 06 Dec 2010 12:39 PM
Posted By docjenser on 03 Nov 2010 02:09 PM
I do not see any reason for reducing GPM manually, all the manufactures data shows that the heat extraction (heating) and the efficiency increase with the increased source flow.
I can, if the system requires 9 GPM for optimal efficiency, why pump 20 GPM though it when the Cost / Benefit ratio is minimal. While a higher source flow may be beneficial, I doubt it makes up for the increased pump load. For my open loop system, I have it set to 9 GPM, according to the Water furance documentation I have, that's the ideal setting for my system.
Just to clarify, is it good to save one pump if you do not need it? Yes! Does it make sense to reduced or throttle back the flow manually but keep both pumps running just to get down to less than 3 gpm/minute? Not much at all. |
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| www.buffalogeothermalheating.com |
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joe.ami
Veteran Member
Posts:4377
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| 08 Dec 2010 10:01 AM |
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Posted By TechGromit on 06 Dec 2010 12:39 PM
Posted By docjenser on 03 Nov 2010 02:09 PM
I do not see any reason for reducing GPM manually, all the manufactures data shows that the heat extraction (heating) and the efficiency increase with the increased source flow.
I can, if the system requires 9 GPM for optimal efficiency, why pump 20 GPM though it when the Cost / Benefit ratio is minimal. While a higher source flow may be beneficial, I doubt it makes up for the increased pump load. For my open loop system, I have it set to 9 GPM, according to the Water furance documentation I have, that's the ideal setting for my system.
TG, With your open loop system, I agree that a lot of extra pumping is extremely undesirable. The discussion of whether higher GPM matters with closed loop is a different one entirely. RE: one or 2 pump centers; folks you can imagine from a contractor perspective of cutting it close versus spend $200 extra now- what the contractor will choose. We are not going to sweat the extra fractional kw pump as it will be unnoticable with new heat pump. Homeowners trying to get consumption down to net zero might worry about it, but few else will. Remember greater flow has a miniscule COP advantage, so the .5kw you save on pumping might be spent on lost COP. Only years of data can answer that one. j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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jonr
Senior Member
Posts:5341
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| 09 Dec 2010 10:35 AM |
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Throttling down decreases GPM but increases delta-P across the
pump -- and power consumption remains essentially unchanged. I used to think this was generally true until I saw actual data. The reduction in flow exceeds the pressure increase and a throttled pump usually uses significantly less energy. For the specific pump in question - I have no idea. |
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