I just started up a new system that I installed myself it consist of:

Horazontal field with 6 1000 Foot 1" HDPE loops 6 feet deep in solid limestone, Bedded with limestone fine screening type material and back filled with topsoil and broken limestone.

I have 1-5 Ton and 1-4 ton units  connected now there will be 1 other unit that is plumbed but not wired yet. They are FHP Aquarius 27 systems

With 98 deg outside temp with the units running on 1st stage only all day long my temps are as follows:

Leaving Water Temp    111.5 Deg
Entering water Temp   101.5 Deg

Measured at the In and Out of the Loop pumps

Total Flow with both units running is 28 GPM

Return air Temp 85 Deg
Supply air Temp 64 Deg

This is on the 5 Ton Unit

No DSH connected yet.

The workers have the garage doors open all day and there are no doors to the attic only plastic covering the openings

The house is Totally insulated with Open Cell Foam Roof Deck, All walls, Between Floors, All interior walls etc. Closed cell under slab ( 9 Sets of foam, )

The house is over 9600 Sq Ft

I am only running the system to test it out and cool things down to be able to work inside with the 108 Heat Index here in Oklahoma.

Question is at this point are the LWT and EWT to high for the system to work correctly?

I have done 2 other systems with deep wells so they have lower EWT and LWT just not sure of the temps with the horozontal loops.

Thanks
Ed

If you just started this system, there is no way that your EWT should be 101°!

You will never last two more weeks, forget about the summer.

How long has the loop been backfilled?

I think something is definitely wrong with the loop.

Is the 6000' of pipe in slinkies?

Who designed the loop?

Was is purged well? Can you get access to each loop to check temperatures?

I would try soaking the loop field. I could be way off but isn't 1000' per ton normal, meaning this loop field is undersized? Isn't limestone a bad conductor, especially when dry?

1.26-1.33 limestone
1.5 dry earth

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

we use it all the time with dx as another way to protect the pipes , because it neutralizes acid . and certainly never had issues .

101 EWT is not good. You might as well be running air source units at that temperature

System sounds underlooped for 9+ tons (you didn't tell us the tonnage of the 3rd as-yet-unconnected unit)

Of course you are conditioning space that is hotter than the outside. I'm interested in loop sizing as well, but will be curious about the performance if you take the free communication with the attic and out doors out of this equation.
j

That's a good point. If the communication with normally unconditioned spaces is causing the units to run 24/7, that's an unnaturally heavy load on the loop.

OTOH Ed stated that the units were running in low stage only, and that a 3rd unit (tonnage unknown) has yet to be operated, so I'm betting he has or will have a loop problem.

Ed - what is the tonnage on the 3rd unit? What are the calculated Manual J building loads and what are the design conditions for the loop?

I was thinking the same thing, but if the soil was 90 degrees outside when he backfilled, I am wondering house long it would take for it to bleed off that heat with the ground surrounding it.  It's solid limestone surrounding the trenches? I wouldn't think the heat transfer be all that good between the two.   

Thanks for all the comments,

Sorry for the delay I could not log on to reply.

A few more details, The original Purge cart I used was a new design that had a pressurized tank with a air relief valve, I purged again today and got lots of air with an old style open top tank type purge cart.

When I left a couple of hours ago my EWT was around 65 deg I think a couple of loops were not flowing correctly due to air before.

I have 75 deg temprorary stats on both units and they have the house cooled down and they are cycling a couple of times a day to maintain temps even with the air in the loops.

The house can be left closed up and only lose a couple of degrees all day long with 98 deg outside temps, It is super Insulated and sealed well if the garage doors are closed
attic temp is about 85 deg now and will continue to cool over the next few days with the system running.

The 4 ton unit is upstairs and has 8 zone dampers, all are open now but will be operating in the next couple of days.

The 3rd unit is a 1.5 ton ( Smallest I could get my hands on ) It is for the master suite only and it is pretty cool there with no unit running at all.

The home automation system will be able to control the units if needed to allow only 1 unit to run at a time. so even if the loop is undersized for the full load I think I will be ok. ( I used Software from Climate Master to calculate and came up with the 6000 Feet number )

The Maunal J called for 15 Ton I think, it was about a year ago when I ran the numbers and have the papers filed away, I derated to 10.5 due to the insulation I put in and the zoned system upstairs.

I also own the Foam Insulation Company so I filled it up with foam, Under slab, Roof Deck all exterior and all interior walls, and a 2" layer over the sheetrock in the attic over the bedrooms.

I will have my WEL setup in a month or so when we get closer to finishing. So I can monitor a little better.

I am also installing a perforated pipe over most the loop field that will take the discharge from my Aerobic Septic system and keep the field moist.

Thanks Again
Ed

65° EWT is more in line with what it should be.   Glad you got it figured out.

EIGHT zones?? My God man!!  I've never seen eight zones on water to air system.


Bergy

All the kids seem to want different temperatures and one zone is for Temperature controlled Storage.

All the duct work is sheet metal with 1.5" of Closed Cell foam on it, The entire house is 99.9% Fiberglass free ( Fire Boxes have internal fiberglass I cant remove! )

A lot of this is to see how energy efficient I can make a large luxury home, A lot of builders don't seem to care what the end operating cost will be on a home.

My neighbor has a 7800 Sq Ft house with 10 seer HVAC Fiberglass Insulation, Poor Energy Seal, Etc. his electric bill in February was over $1200.00 ( Builder saved him lots of money up front! ) Can't get upstairs below 80 Deg with the current 95 Plus temps.
His units run non stop.

Two doors down I Spray foamed a house that is a little over 7000 Sq Ft it has High Efficiency HVAC Good Quality windows,doors Tight weather seal, Highest electric bill was $144.00 It probably cost 10,000.00 more to build it right
Payback will be pretty quick.

Ed

Sorry, I'm with Bergy. 9 zones (counting master) indicates poor knowledge of duct systems. Should have gone water to water.
J

Ed, take a look at http://welserver.com/WEL0043/ for an example of setting up a WEL monitoring system for multiple units.  This is my site, and I'd be happy to answer any questions you may have.

Best regards,

Bill

I am interested in seeing the WEL results when just one of the 8 zones is calling for cooling.

agree 8 zones is a disaster waiting to happen

I dont like 4 , 3 is my usual line

My 3 ton unit has 3 zones.  Considerable effort was spent getting the airflows to be proper and within spec, particularly in single zone situations.  Additionally, my zoning controller is set to not allow 2nd stage at all unless all 3 zones are calling for heating/cooling.  With the 3 zones dedicated to a master bedroom, 2 more bedrooms, and a study, it's rare that all 3 zones are simulaneously on.

See the later charts at http://welserver.com/WEL0043/ for the 3 ton unit's operation (WaterFurance water-to-air Envision 2 stage variable speed) with a 3 zone controller in place.

It's hard to imagine it being possible to design an 8 zone system to be within manufacturer specs for airflow across the coil, or for enough air velocity to the rooms if airflow is maintained to spec across the coil with extra large duct sizing.  I'll look forward to seeing how it's done.

Best regards,

Bill

I have 4, spread over 3 levels, but I need (and now have in hand but not installed) a small bypass damper.

Geo Fan, Joe.Ami - What do you see as a potential problem with multiple zones IE: more than 3 ? please explain what I am missing.


I see It as a simple matter of using an electronic bypass damper and controlling the Variable speed fan to maintain required airflow, and never needing the 2nd stage unless multiple zones are calling for air and that just won't happen.
There will be an air flow monitor in the supply duct to make sure there is proper airflow across the coil.

The system will operate 1 heat strip and open a large zone to dehumidify if needed.

Keep in mind this is a house over 9800 Sq Ft, with large rooms so the zones all have 2 12" Ducts plus 1 8" minimum, Most have 4 12"

All zones have 14" or larger dampers So I have good air flow even with 1 zone only in use. Air velocity is low if all zones are open
but that will really never happen except for a few days while I finish wiring all the dampers and stats.

I think it will prove to be an extremely efficient system, I may be wrong but It's my House and my Money so I am the only one out anything if it has to be redesigned.

Ed