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Looking for help with a Waterfurnace system that does not work
Last Post 03 Mar 2011 01:32 PM by TechGromit. 132 Replies. |
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arkie6
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Posts:1453
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| 10 Feb 2011 10:34 AM |
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Posted By docjenser on 09 Feb 2011 09:46 PM
Then you are supporting 8 tons of heatpumps with an 8-9 tons loop...
Did you really mean to type "8-9 tons loop."? Was that a typo? 765' of bore hole looks more like ~5 tons of geothermal loop @ 150' / ton. Maybe as much as 6 tons under optimum conditions. |
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arkie6
Veteran Member
Posts:1453
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| 10 Feb 2011 10:43 AM |
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Princeton,
I never did see where you replied back with how you arrived at 2200 sq ft for your house. How did you come up with this number?
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Princeton N.J.
New Member
Posts:39
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| 10 Feb 2011 10:46 AM |
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I made a mistake I think, because on the Manual J it has my house listed as having 3000 sf. I guess my measurements weren't exact. Sorry. |
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docjenser
Veteran Member
Posts:1400
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| 10 Feb 2011 11:04 AM |
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Posted By arkie6 on 10 Feb 2011 10:34 AM
Posted By docjenser on 09 Feb 2011 09:46 PM
"But in their opinion (and Charles'), nothing is really going to work correctly until we drill another bore hole."
Then you are supporting 8 tons of heatpumps with an 8-9 tons loop...
Did you really mean to type "8-9 tons loop."? Was that a typo? 765' of bore hole looks more like ~5 tons of geothermal loop @ 150' / ton. Maybe as much as 6 tons under optimum conditions.
I kept saying that right now they have 5-6 ton loop capacity. This was in response to the comment to drill another borehole, which would give them about 2-3 tons more capacity....However, it would not fix their inherent problem. |
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| www.buffalogeothermalheating.com |
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docjenser
Veteran Member
Posts:1400
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| 10 Feb 2011 11:10 AM |
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Posted By Texas Cooler on 10 Feb 2011 08:19 AM
Posted By docjenser on 09 Feb 2011 09:46 PM
Then you are supporting 8 tons of heatpumps with an 8-9 tons loop. May be it is not the most favorable thought here for you, but given your house size, that is a huge load. None of your problems will go away by drilling another hole, the pumps might work 5% more efficient by raising the the EWT from 25 to 30 degrees, but they will still have a similar run time to put the BTUs in your house. Thus your operating costs will not go down! The problem is in the house from the data you have given us, not in the loop primarily. It is my belief that the problem is not the equipment or the loop. If this was installed with a razor thin margin for error, any problem will be magnified.
This is a direct quote from Manual D Residential Duct Systems, Section 3 first para. "...It is not uncommon for poor heating and cooling performance to be attributed to insufficient equipment size when the actual problem was caused by a restrictive duct system...." Emphasis added.
To me, either excess btu's are being lost (house issue) or not enough btu's are being transferred from the equipment to the house (duct issue)
If the issue would be the distribution system, the heatpumps would not be able to reject the heat into the house, and thus extract lesser heat from the ground. However, the amount of BTUs were extracted from the ground given his EWT of 25 F right now, and they had to go somewhere, so it is unlikely the distribution system.
Inefficient ductwork would not explain the low EWT, a large house load vs a small loop does. |
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docjenser
Veteran Member
Posts:1400
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| 10 Feb 2011 12:09 PM |
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Posted By Princeton N.J. on 10 Feb 2011 09:46 AM
So you mean that if everything were 5% more efficient, the cost of running the system would be the same? Wouldn't 5% increased efficiency translate into smoother operation (fewer lock-outs) and less expense? And if our loop-to-ton ratio is OK, I wonder why shorter loops aren't more common, because they do save a lot of money at the outset. I'd appreciate your thoughts on that. Your point is very interesting to me, because I would like to think that my basic system is workable, if not idea. Thx.
The entire purpose of the loopfield is to get the EWT within the operating range of the heatpumps. The heatpumps are rated at 32 F, and when they standardized geo designs they were coming up with min EWT of 30 degrees which would give them enough safety margins to account for all occasions, differences in grouting material, different thermal conductivities, prolonged times of extreme cold outside temps etc. That way one would have a loop which would pretty much work all the time, under most variables and circumstances. As a rule of thumb, each degrees of delta the heatpump has to make up between the EWT and the output gives you 1-2% more efficiency. So by lowering your return air temperature, or in hydronic applications the water temperature, you can gain some efficiency by increasing your COP.
Most installers use those rule of thumb, they were developed to allow a widespread utilization of geo heatpump technology without complex design parameters. Now, once you divert from that standard setup, you need to know very much what you are doing, that is why commercial jobs usually need a customized geo design with ground conductivity testing, and the grouting is exactly specified by the loop designer. There they run the algorithms and balance upfront cost versus increased efficiency.
I tend to be generous with loop sizes in residential horizontal applications because it allows me to speed up install time, and does not cost me as much as drilling. With vertical loopfields, we sometimes shortloop on purpose, because dropping the EWT down to lets say 28 degrees will costs you maybe 4-5 percent in efficiency, may be increase your operating costs by $80-$100 annually, but also may be allows for smaller circulation pumps, saving you $80 per year. In addition, a shorter loop might save you $5000-$6000 in upfront drilling costs. It would be economical a bad choice to invest $5k to save $100 per year.
Usually I advise people not to touch the formulas which have worked, and I had lively discussions with Joe here about the subject. If you are skilled and know what you are doing, you can touch those safety margins and actually do your customer a favor.
Conversely to your thought your installer might have been someone who knows all that and saved you a lot of money upfront by shorting your loop, at the expense of may be a $100 (just a guess here) higher operating costs annually).
So in summary, in order to allow a widespread use of residential geothermal application, they standardized the installment parameters in order to allow bulletproof geothermal application, if you follow those standards! You can tell that some people do not do that, and that is when problems surface. In your case, you feed us a pieces information, this is the first time you mentioned lockdown. Manufacture's operating range is usually down to 25F EWT, most of them publish specs down to 20F EWT. The operating range is quite large. |
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| www.buffalogeothermalheating.com |
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Texas Cooler
New Member
Posts:22
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| 10 Feb 2011 05:26 PM |
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Posted By docjenser on 10 Feb 2011 11:10 AM
Posted By Texas Cooler on 10 Feb 2011 08:19 AM
Posted By docjenser on 09 Feb 2011 09:46 PM
Then you are supporting 8 tons of heatpumps with an 8-9 tons loop. May be it is not the most favorable thought here for you, but given your house size, that is a huge load. None of your problems will go away by drilling another hole, the pumps might work 5% more efficient by raising the the EWT from 25 to 30 degrees, but they will still have a similar run time to put the BTUs in your house. Thus your operating costs will not go down! The problem is in the house from the data you have given us, not in the loop primarily. It is my belief that the problem is not the equipment or the loop. If this was installed with a razor thin margin for error, any problem will be magnified.
This is a direct quote from Manual D Residential Duct Systems, Section 3 first para. "...It is not uncommon for poor heating and cooling performance to be attributed to insufficient equipment size when the actual problem was caused by a restrictive duct system...." Emphasis added.
To me, either excess btu's are being lost (house issue) or not enough btu's are being transferred from the equipment to the house (duct issue)
If the issue would be the distribution system, the heatpumps would not be able to reject the heat into the house, and thus extract lesser heat from the ground. However, the amount of BTUs were extracted from the ground given his EWT of 25 F right now, and they had to go somewhere, so it is unlikely the distribution system. Inefficient ductwork would not explain the low EWT, a large house load vs a small loop does. I don't know the dimensions of the ducts, but I believe they are standard: running through the attic, we have two main trunk lines, with flex duct offshoots. It's all pretty new, too. The attic is insulated. But the heat does blow through diffusers placed in the celing, which his very ineffecient because our ceilings are high and heat rises. So I know that's part of the problem.
I agree that this system is short looped and losing more heat than what is delivered. The above paragraph posted by the OP causes me to want to check off all the easy, cheap fixes before commiting to another loop. Since the the duct is "running through th attic", it is possible that he is losing some btu's through leaky connections or a less than optimal configuration. As an example, assume a 66* EAT and a 86* LAT (just assumptions as the OP has never posted these). The TD would be 20*. After flowing thru all the ductwork in the attic, the temperature at the supply ductwork is now only 84*. The ductwork is losing 2* during its run. Divide the duct loss (2*) by the original temperature rise (20*) and you can see that the system has lost 10% of the heat that was produced. Secondly, as others have advised, a blower door test would be money well spent as would an infra-red temp loss audit. IMO, I would try fixing the house before handing over money for additional loops. |
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joe.ami
Veteran Member
Posts:4377
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| 11 Feb 2011 08:31 AM |
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Posted By Princeton N.J. on 10 Feb 2011 09:46 AM
So you mean that if everything were 5% more efficient, the cost of running the system would be the same? Wouldn't 5% increased efficiency translate into smoother operation (fewer lock-outs) and less expense? Don't recall mention of lock-outs either.....that points at the loops. j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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TechGromit
Advanced Member
Posts:634
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| 14 Feb 2011 01:10 PM |
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Posted By Princeton N.J. on 05 Feb 2011 08:13 PM
It seems to cost a lot to run the system. Our most recent electric bill probably contained about $600.00 worth of heating costs. We have a meter that allows for off-peak/on-peak metering, and we try to use that option well. We keep the house at an even 65 degrees and have sealed up windows, doors, cracks. Nonetheless, it's not as though we have an extremely tight or efficient house. But $600 is so much to pay for geo heat, I think it's probably a sign that the system isn't running as efficiently as it could.
Just out of curiosity, how warm is the air coming out of the heating vents? I ask because I had a Geothermal system installed by a contractor that wasn't familiar with the Water Furnace product line. They connected the AUX heat and the blower motor to the electrical panel, but completely neglected to run a separate circuit for the compressor. I only realized after the heat season began (it was installed in October) that the output was way too hot for a Geothermal system. Having experience with them before, I know the air coming out of the vents should be Luke warm, not warm or hot by any means. Warm/hot air means you running on AUX. I had the installer return and run another circuit for the Compressor and it's been fine for the past 2 years now. A $600 electric bill indicates to me your running on AUX heat, I have a 3300 sq ft house and my highest bill so far was $480, and it was only this high because I use a Heat Pump for my upstairs zone and a ASHP is worthless when the outside temperatures are below freezing. I can't imagine your Compressor isn't connected, I would think you would have noticed you didn't have any air conditioning, especially this past summer. > Our most recent electric bill probably contained about $600.00 worth of heating costs. What is you base electric bill, How much is your bill in say October when it's cool enough to do without air conditioning and warm enough to do without heat? P.S. I live in New Jersey too. |
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docjenser
Veteran Member
Posts:1400
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| 15 Feb 2011 01:39 PM |
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If his compressors would not be running, his loop would not be at 25F EWT. That indicates that his compressors are running heavily..... |
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| www.buffalogeothermalheating.com |
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GeoJohn
New Member
Posts:12
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| 15 Feb 2011 02:43 PM |
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Princeton NJ - Before you drill that extra hole...
Since you have more than one bore hole, before you drill another bore hole I would check two things.
1.) Have the company who installed your system flush the loops to make sure that there is no air blocking flow in your loops. It is possible that you are only working on two of the three loops (maybe one of the loops is air blocked)
2.) While uncommon, it is possible that the grouting in the bore hole/wells has dropped. Meaning your loops (or a loop) may not be getting much of any thermal conductivity. While this is rare, you could have them ask the well driller for specific notes on conditions. Did they have to use more Bentonite or thermally enhanced grout than they normally do? When the grout of a well drops it is easily visible when they clear dirt away from the top of the well. This is less expensive than drilling another well.
3.) As a contractor it is difficult to work with existing duct work, especially if they added a second system and especially if the duct work is hidden by drywall.
To include my two cents, with your house being on stilts/pilers and having a large amount of glass, you do have a different load situation that Manual J may or may not calculate effectively for and to me would be more suspect as a factor to your inadequate conditioning. But with out all of the numbers and facts it's merely conjecture.
If they flush the loops and there is no air blocking flow then that narrows it down to the loops.
Good luck with this situation. |
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engineer
Veteran Member
Posts:2749
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| 16 Feb 2011 12:55 AM |
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Man J will accomodate those construction details, but not if it is crippled by GIGO by the operator (garbage in, garbage out)
Glass is entered by exposure direction, overhang, shading, insect screens, SHGC and U-factor
Floor load arising from a house being on stilts would be reasonably approximated by specifying the floor as being ove an open crawl space. |
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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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joe.ami
Veteran Member
Posts:4377
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| 16 Feb 2011 07:55 AM |
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GIGO........10 pages of symptoms before first mentioned lock-out.....  j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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engineer
Veteran Member
Posts:2749
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| 16 Feb 2011 08:15 PM |
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Details, details...what's a lockout or two among friends?
That bit about stilts is a potentially substantial load detail. |
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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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WF_Inc.
New Member
Posts:88
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| 17 Feb 2011 04:55 PM |
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Princeton N.J.,
WaterFurnace is an equipment manufacturer. We sell to HVAC contractors and distributors, who are independently owned and operated, and not under our control. As for recommending a contractor; unfortunately, we are unable to do this. We would suggest that anytime you hire a contractor, you check with the Better Business Bureau, and request references from their customers.
In reference to your utility bills, we have requested a copy of the WaterFurnace Energy Analysis, which provides the estimated operating costs of the WaterFurnace equipment. If you do not have one, any WaterFurnace dealer can provide this.
We have also requested actual copies of the past 24 month’s utility bills. At this time, we have only received 7 months of bills from 2007-2008. Please forward the utility bills for 2009 and 2010. Unfortunately, without this information we are unable to get a clear understanding of your annual electric costs.
WaterFurnace International, Inc. |
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Princeton N.J.
New Member
Posts:39
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| 20 Feb 2011 10:10 AM |
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WaterFurnace,
But you did recommend a contractor. That's the issue. In searching for an installer, we first thought to contact WaterFurnace. And from WaterFurnace, we were given the name of the contractor we used, who was highly recommended by WFI. That was how we made our decision in choosing an installer.
Any contractor can supply a consumer with good references. Even the worst, have at least one or two satisfied customers (or friends) willing to speak positively on their behalf. Again, we thought that the most unbiased and valuable opinion would come from WFI. We thought WFI would give us the gold standard opinion that we sought.
If at any time WFI had said, "sorry, we can't recommend," we would have understood. That was never the case. Our question now is why doesn't WFI stand behind its recommendations? Behind the work done by its "authorized" dealers?
We have been very patient in asking for your company's help. We have resisted posting our consumer complaint on the many online forums where a company's reputation is at stake. But it is insulting to ask us to accept the assertation that "we don't recommend" anymore. It simply is not true. If a mistake was made, we expect a reputable company to take responsibility and help its customers.
Please respond at your earliest convenience. More electric bills will be sent. But suffice it to say that we use more electricity to run our geo system in two cold-weather months than the average American home uses in a year. And our heat is never set above 64 (frequently much lower). We have a lemon of a system.
Please don't ignore a good customer with hopes of being a satisfied one as well. Thank you. |
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joe.ami
Veteran Member
Posts:4377
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| 20 Feb 2011 10:49 AM |
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Flushing the loops sounds like a good next step......
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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WF_Inc.
New Member
Posts:88
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| 21 Feb 2011 12:31 PM |
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Princeton N.J.,
We would be interested to know who you spoke with at WaterFurnace. As for authorized dealers, we do not authorize or certify anyone to perform work on our behalf. We do not have any intention of ignoring you or your concerns; this is why we contacted you. We are interested in looking into your concerns; however, we will need the requested information in order to do so.
WaterFurnace International, Inc. |
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docjenser
Veteran Member
Posts:1400
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| 22 Feb 2011 01:06 AM |
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Princeton,
You keep ignoring the fact that your heatpumps had extracted a large amount of out of the ground, nothing points to significant flaws from the installer or WF. Where did the heat go? And what did WF or the installer do wrong? Why makes it a lemon of a system when you house is so inefficient. I have no relationship with WF, although I put a few of their pumps in. But you seem to ignore the obvious, |
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| www.buffalogeothermalheating.com |
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Princeton N.J.
New Member
Posts:39
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| 22 Feb 2011 08:02 AM |
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I see your point. But I have two questions: how do you know we extracted a lot of heat from the loop? I've been told that the loop is cold because it's too short, not because heat has been taken out of it. I'd like to know the other side of the argument.
Second, it's true that our house is not as "tight" as it could or should be. But no matter, wouldn't it be somewhat better if we had a system built upon the right loop-to-tonnage proportions? It may not be perfect, but it could be better.
Thanks for your honest opinion. |
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