Hot Geothermal loops!! Can we use our pool to cool??

Homemom

This is how we pipe from the loop field to two Geo units.

Bergy

 

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Sorry, some of the photos are sideways.

 

Re: Homemom

Is it normal and customary to use two pumps with the two units if there is only one loop field? Thanks for the pic, it helps.

I only have 1 "flow center". Ok, still learning, does the 3 ton need a different flow rate than the 5 ton? And, is there more than one way to skin this cat?

What do you think of the plumbing job currently? (This was re-done last year by the good commercial Geo contractor - only one pump was supplied by the original GeoContractor.)

 

I'm stumped.

 

I think we can fix this

It does not look like we have enough flow or check valves. I am blowing up the photos to see what is going on.

Where do the black pipes coming out of the flow center go?

 

Flow

There is not enough flow, as both units need more.

The near unit piping will not allow enough flow.

Each unit looks the same size and/or equal they are not so internally. One is 5 tons the other is 3 tons. A total of 8 tons nominal delivery is 12,000 BTUH X 8 = 96,000 BTUH. The piping to and from the units is only 3/4" copper. That is not enough. They tie together in Bergy's bull head T diagram with out flow check valves, then go off to lots of money in the landscaping.

Flow centers are not about flow. They are about non-engineering. If one is good two are better, one pushes and the other pulls. We spend days and weeks here debating thermal transfer when we should be talking about flow.

We need to look at flow, as without flow there are no reynolds numbers.

This system is under piped and under pumped. I will walk from Cleveland to LV and north to prove it.

I had a great day Friday, 5/08/09, I met the guy that invented CPVC. Bob is a gentleman.

I will work the pictures to get numbers off the pumps, I am sure they are not enough to pump 8 loops and the machines.

We need 3 GPM/ton on a colmax chassie running R-22 plus all the pipe in the ground. I pray that it is not all 3/4". If it is we can still fix it without digging.

 

BTW, homemom

thanks for the pix. Call me anytime. I will work up your fix and post it here if it is ok with you.

Mark

 

More PIcs of system

MORE PICS - Color Coded

Pics:
IMG_1714.JPG Green is freon to Air Handlers
Pink is Hot water - To and from the water heaters.

IMG_1715.JPG Orange shows loop cycle There is a T split.

IMG_1716.JPG More Orange loops cycle

IMG_1717.JPG More pics

IMG_1720.JPG Temps L to R.
1- Water coming IN From loops. (In am temp is in the 80's)
2- Water OUT from 5 ton
3- Water OUT from 3 ton

And it's only May....

FYI - Just remembered, the freon was "EXTREMELY" low the first summer we used it....Guy said he filled it up... Could there be a leak??

http://www.geoexchange.org/forum/attachment.php?attachmentid=205&stc=1&d=1242089738Hope this helps - If I can get other numbers etc. Please let me know.
Thanks!

 

Homemom

HomeMom,

So, you only have one flow center for two heat pumps. I don't see any wiring that would allow the circulators to run separately. This means they both run when either heat pump is calling, over-pumping the three ton when only it's calling. (Assuming the circs are sized to provide the proper flow to the units.) Yes, the three ton needs less flow than the five ton.

As far as the piping goes....OMG!!!!!!!!!! This was from the GOOD contractor?? Let's start where the flow starts...

The rubber hose laying on the floor, I assume, is the supply and return for the loop field. NO! NO! NO! The hose kit connects between the flow center and heat pump. There should be no more than 12 Ft. TOTAL of flex hose BETWEEN the flow center and the heat pump. The headers should also be insulated.

NEXT... The heat pumps should NOT BE STACKED!!! I would not want to be the service tech that has to work on that! God forbid the lower compressor ever needs to be changed.

The Tranquility 27 is R 410-A (Is it not?) and the copper fittings should be brazed not soft soldered!!!!(EDIT...Looking closer at the pictures it does appear like the refrigerant fittings are brazed.)

It's hard to tell but I think the copper between the flow center and the heat pumps is 1". IF it is, it is not large enough. It should be 1 1/4" up to the point where it splits to the separate units then it can be reduced to 1". Actually, it should not be hard piped between the unit and the wall mounted flow center. Too much of a chance to transfer vibration into the structure.

I only see Peets Ports on the "Water In" side of the coil. There should be service ports on the incoming AND outgoing water piping.

The desuperheater pipe needs to be up-sized from 1/2" to 3/4" where the two join into one.

I hate to be SO critical but this is NOT an example quality craftsmanship.

Bergy

 

Hey Guys!!

What is the device by the yellow "out 3 ton" tag? It has Peets ports on each side of what looks like a union. Is that some sort of circuit setter? I've never seen one before.

Bergy

 

Looking at your temps ( which may not be accurate), I would say:

1) the flows are not balanced properly between heat pumps (LWTs should match)

2) the temperature delta is typical (which suggests flow is adequate)


Maybe the circuit setters are there so someone could measure the flow rates?

 

IMG_1724.JPG Under the 2 units - loops

IMG_1730.JPG More Temps (10pm)
These are just outdoor thermostats I picked up attached to the piping
- fairly accurate. But Not perfect

IMG_1731.JPG Front/side view shows some electrical.

The Good contractor has been doing commercial Geo for a long time.
He sent his tech to do the plumbing. I found the ClimateMaster installation book... Think I'll do a bit of reading.

It's late. Thanks again- I'll see you later.

 

Device by 3 ton tag - I'd guess (and it is a guess) by the P/T plugs that it is a flow control valve of sorts.

 

I'll stick with your loops being your main problem. Maybe just too small, some are plugged, air in the lines on some of them.

If you can get access to the lines that feed each vertical loop, you can figure it out.

 

4 are under the driveway. 1 near/under walkway. 3 accessible apox 3 feet under dirt in the front yard.

Climatemaster installation manual
http://www.climatemaster.com/downloads/97B0047N01.pdf

 

Let me

crunch the numbers and look at the new photos. Then we can run the loops without the heat pumps to check their opperation. I have a real life system to solve this am.

 

I understand that the vertical loops themselves are hard to access, but is there a manifold that you can get to?

 

How to fix this system

I am going to break the solutions into chewable parts, which will be co-dependant for success in getting this system to work.

The way I would go about solving the over heated loop issue:

The first issue I see is there is no way to know if we have air in the loop field. Looking at the photos I see no way to attach a perg cart nor any way to isolate the machines from the loops. If there is still air in the loop field those little pumps can run all day and not move any or much water. Given the delta T in heating found on page 40 of the I/O manual we are moving water through the machines, but my guess is we are not moving much. That is shown by Homemom's thermostats, (Good solution and good job, BTW) we are moving water through the machines. We do not know what is going through which machine when.

Addressing the loops, I would plumb in a set of loop servicing valves and hose connections. I would include ball valves so I can control where the flow goes. I would add pressure gauge tees with service valves, screw in pressure gauges and leave them there. At this point we can add temperature sensors to allow us to see what is going on with the geothermal exchange in the loops. I do not think I would add weighted or spring checks and their servicing valves between the flow center and the loop field yet.

Once we are sure we have burped the loop and Homemom finds the loop material size, we can use our pressure gages and or piping tables to learn what the head pressure drop is through the loop field.

We can now determine if the loop will work, not guess if it will work.

I wish I could see what size pipe is coming and going to the loop field. If it is 1" the system might work. 1 1/4" would be sweet. Homemom can you measure the pipe or read a size off the fitting.

Most of you folks following this thread have heard me rant about flow and pump sizing so we will pretend the little pumps will do what we need. What we need them to do is push water out to the end of the field and then back. I feel two small pumps, one pushing and the other pulling is not saving anything over one properly sized pump. We will do the pumps in another post to this thread.

Now lets look at what is happening the way this system is plumbed. Bergy put up a nice drawing showing how he would do this idea. I would say his idea is much the same as mine, as he uses a pump for each machine. As built we have no way to control where the water goes as it leaves the flow center.

The big brass looking gizmo's, the first item in the piping as it comes out of the machines, are flow controllers the likes of which I am not familiar. I found them in the I/O manual around page 10. They are followed by smaller brass things which may be spring checks. So the plumber was trying to do two things with these parts, control flow and which way the water goes. From Ohio it looks like they should work.

The problem is we need to stop the water going to each machine if it is not running. Unless there is an internal zone or solenoid valve in the machine the water can tour a non-running heat pump at will. It will be going the correct direction, but is not needed if the machine is not calling for operation, so it is not going back to the loop field to heat up or cool down.

I am running out of time and page, (I really do do this stuff for a living) so I will continue later today.

 

Mark

If you look closely at the flow center pics you can see it's upside down from "normal". There are three way T valves on the side and some sort of port on the front just under the circs.

The HDPE pipe from the loop field looks to be 1 1/4" with 1" flex hose kit going to the flow center. My question would be...Is 1 1/4" large enough for 8 tons? 8 tons X 3 GPM/ton = 24 GPM.

Bergy

 

Bergy:

Page 40 or so of the I/O manual says we need a delta t of 9 to 12* F at 3 gpm per ton.

So taking my B&G systemsizer in hand I set for the delta T and for 24 gpm and the slide rules says, we need over an inch and under 1 1/4" using type L copper plumbing. So this system will work if that is 1 1/4" under the equipment stand.

I will run numbers and type the piping corrections to the machines later today.

I think we can make this work with the correct pumps and an air free loop field.

Edit: "It is a damn narrow minded man, that can only think of one way to spell a word", Andrew Jackson. I was on my way out the door when Bergy typed back, we type at another board together, so I did not edit this post before this edit.