I've recently contracted for the installation of a WF 2.5 ton Envision system in my home and am awaiting issuance of the required permit from the state to drill.

In my initial discussions with the contractor (experienced and reputable) he stated he was going to dig 2 wells, each 280'. Last week he came out with the driller and advised that it was going to be 1 well, 300' with 1 1/4" pipe. The contract does not specify the number of wells or their depth. I have just emailed him and asked him to explain the reason for the change, which seems pretty substantial to me.

I'd appreciate any feedback from the members of this forum as to questions I might ask the contractor as to his reasoning behind the change as well as any other comments you might care to make.

Thanks in advance.

PLEASE NOTE: I received a reply from the contractor after I posted this message. He states that there was some confusion since several people were involved in the quote process and his initial statement to me that my system would have 2 wells, each 280' was made in error. The 2 wells were part of a different quote for another customer. My system was always calling for the one well.

I will ask him for the design particulars the next time I see him.

Sorry for any confusion (other than mine) I may have caused.

kind of slim on info provided, but one 300' well for a 2.5 ton system is on the short side of average.

__________________
Dewayne Dean

www.palacegeothermal.com
"dean@palacegeothermal.com"
http://welserver.com/WEL0114/

We heat and cool with dirt.
Why settle for 90% when you can have 400%

Geothermal, the reliable renewable.
The sun doesn't have to shine,
The wind doesn't have to blow.

Thanks for the reply.

Sorry about the info being slim, but that's exactly my quandry.

How do I go about educating myself so I can ask intelligent questions of the installer?

Bidder should be able to provide a design document to support a particular loop configuration.

It should account for soil composition and moisture, design heating and cooling load, max and min loop temps, loop GPM, maintaining turbulent flow, and what pump is to be used.

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Curt Kinder

www.hoviscustombuilders.com

Without data, you have but an opinion.
No thing done well is as simple as it seems

Our 3-ton Envision (NDV038) is running on a single 450' well + 50' trench, 1.25" pipe.
That comes to nearly 1100' total pipe (including indoor plumbing). A single Grundfos
UP26-99 circ pump (245 watts) is just enough to satisfy WF's recommended flow rate.
I'm getting 8 GPM w 20% methanol antifreeze. Online 15 months, works as advertised.

I kinda like the unbranched single-bore approach (if you can get away with it). SIMPLE,
minimum # of welds, easy flushing, no manifolds, high turbulence (Reynolds# = 5890).

Regarding total bore length, you'll have to rely on the experience of local drillers/installers.
(Thanks to extremely favorable geology, 150 ft/ton is more than adequate in my location.)

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One measurement is worth a thousand expert opinions.

We run ~150'/ton of 3/4" in my area. 11/4" certainly would offer more btu transfer.
If installer's references are good, you may be worried about something that simply was a mis-statement.
There are many things a geo installer can goof up, but vertical loops are generally (not always but it appears to be true in your case) subcontracted to drillers who may have more installs (due to working for multiple contractors) than the HVAC bidder. I tell customers flat out that they are the expert and "I think that they'll do such and such", but I will always yield to their expertise if they have a different idea.
In my area there are not a lot of geo drillers so someone may get 3 bids on a job and have the same driller regardless of who they hire.
Curiously, the most common geo problems I see are poorly sized equipment and poorly sized ductwork. Loop sizing goof ups are among the least common.
Yet people always focus on the loops.........
How did your installer's references check-out? What did other bidder's suggest? These are better measuring sticks.....
Good Luck,
Joe

__________________
Joe Hardin
AMI Geothermal
"We Dig Comfort"
www.amicontracting.com

Thanks for the replies. This is a great forum!

I've known the contractor I'm using for 10 years. He installed the HVAC when I renovated this house 10 years ago. He's one of the best in the area. I got two quotes last fall but don't remember the details. I got a fresh quote (lower than the one he gave me last fall) from the one I'm using and told him to go ahead so I've got nothing to compare his bid against.

I will ask him for the design document to satisfy my curiousity and if I have any further questions I'll post again. He did take me to see one installation he's doing now for one of our local celebrities and I've spoken with 3 others that he's done installations for. Everyone says he's great.

I tend to be a worry wart, especially when it comes to something this significant. I'll feel better when the system is up and running. I got another $500 propane bill just today so I'm all the more eager to get this thing going.

Thanks again for the responses.

Installed the 2.5 ton WF NDV026B and have had some unexpected, and yet to be accounted for, problems.

First, my electricity consumption for the initial months usage was significantly higher than the other similar periods in the last 3 1/2 years. 1230 kwh as opposed to the usual 700-800 kwh during the previous 2 prior periods. Granted, it's been a hot summer but this seems inordinately high to me and very disappointing as well. I previously was running a 2.5 ton Carrier central air unit installed in 2000.

Second, there's a constant whine coming from the system when it's running. I compare it to the sound of a wood chipper running at full speed (but with no wood being fed) in the distance. At first, that's actually what I thought it was. I hear the noise equally when I put my ear to either of the circulating water pipes, but not in the ductwork. I believe it's being transmitted from the pipes through the metal brackets that support them into the floor joists. The intensity of the sound varies in different parts of the house. It's actually loudest in the corner of the house that's the furthest away (~50 ') from the WF unit and at least 20' distant from the nearest incoming and outgoing pipes.

The contractor is coming next week but I wanted to educate myself as much as possible prior to his visit.

Thanks in advance for any and all input.

We hear some noise telegraphing through our loop pipes in the crawlspace below our master bedroom (20 -25 feet away from the pumps) with our system. We mainly notice it at night when things are relatively quiet. Fortunately the sound isn't too obtrusive for us. It sounds like your noise is a bit louder.

In the main section of our house, we have Armaflex pipe insulation on our loop pipes, and the hanger straps go around the insulation (to the floor joists). This may give us some insulation from the vibration/noise. In our crawlspace, the pipes are not mounted to the joists.

Are your thermostat settings the same as with the old system?

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WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon.

Thanks for the response. I'm in the process of looking up and compiling CDDs for our area for the last couple of years so I can come up with some sort of meaningful comparison. We barely used the AC last year since it was a cool summer, so I have to go back to 2008.

Good question about thermostat settings. As I recall, we kept the t'stat at 78 degrees in 2008 and, with the new system, are keeping it at 74-75 degrees. Would that be enough to account for the dramatic increase in kwh?