Help, leaking horizontal loop, what do I do?

I am a homeowner who has a pressurized horizontal closed loop that loses pressure over time. My contractor used to have to add water to the loop every 4 to 5 months, just yesterday it was only a month since the last refill. When water is added, the contractor only needs to add a very small amount, approx. less than a quart to bring the loop back up to pressure.

The contractor has searched everywhere inside the house where the loop is exposed and also inside the unit for leaks, but has been unable to find one. We are both of the opinion that the leak is somewhere underground. The loop is about 12 years old and began losing pressure about 5 years ago.

The contractor has suggested installing a B & D non-pressurized flow center instead of digging to try to find the leak. Does anyone have any ideas on how one might find a pinhole size underground leak? Anyone ever try installing a B & D non-pressurized flow center on a leaking loop and how did it work out?

I plan to be in this house for many years to come and want to fix the problem right and still have a cost effective fix. Two other suggestions he has had was plumbing in an autofill mechanism to the loop or using Geothermal Fix-a-Leak. I don't like the autofill mechanism because you never know what the mix ratio of methanol/water is and eventually the loop will become diluted with water. I don't like the Geothermal Fix-a-Leak solution because I believe it will hurt the efficiency of the system having slimy stuff coat everything inside the loop. My geothermal system is little undersized for the house to begin with and I need all the heat I can get out of it.

I have also read about evacuating the loop and putting helium in it and then using a helium detector above the ground where the pipe are laid to find the leak. With the leak in the loop being so small, I am skeptical about whether this would work or not. It is said that helium is such a small atom that it will leak up to the surface of the ground and be detected.

Any suggestions or advice you have on this matter would be much appreciated.

 

With a leak that small, any kind of detection will be very hard to find.

I would try the fix a leak product. We have used this once and it seemed to work.

Then if the leak persists, or your system performance degrades significantly, you can think about replacing the loop.

When you say that your system is a little undersized, are you referring to the heat pump or the loop?

How cold does the loop get in the winter?

 

The geothermal unit is small for the size house it was put in. The contractor should have put a larger geothermal unit in. The loop seems sized properly. The coldest I have ever seen the loop get is about 30 degrees F.

Thank you for the reply.

 

One other option to the non-pressurised flow center would be an auto fill with check valve. It would maintain the system pressure at what ever you choose and would be less costly than changing your system over from pressurised to non.
hope this helps
Eric

 

I have the same problem and here is how I handle it. Can't find the leak after years of looking. So small that I only lose a couple ounces a year. Like to keep 30 PSI so when it gets low (5 -10 PSI) I take out my gallon insect sprayer that I modified. It has a tip used to inflate basketballs or footballs, a pressure guage and a couple of valves. Have a gallon of -20F Methanol car windshield washer solution on hand from Wal-Marts, fill the sprayer, pump up to fill the hose and remove the air. Put needle valve in P/T port at unit and pump away. When you hit 30 PSI or so just close valve and let unit stabilize. If you are happy take out the needle remove the pressure on the tank. I like to put the fluid back in it's original container and put the cap on tight. I don't know how fast the methanol will leach out of the plastic bottle but I'm guessing it stays fresh for a long time this way. All the parts came from either HD or Tractor Supply. If you run glycol then you can get -25F at Wall-Mart instead.

Get a good quality pump so you can get the 30 PSI. Some have pressure release spring that will not allow you to get to the 30 PSI before it opens. The SOLO brand is good I have one that gets to 45 PSI before it pops.

good luck

Walt

 

Loop Leak

For all practical intents and purposes the leak should be fixed. You don't want to get dirt into the system.

There is a product called "Geo-Loop Conditioner" available from Geothermal Supply Co., Inc. - Geothermal Supply Company

We have used it for many years on small leaks. The product must be added to the loop fluid and the system circulated for 24 hours. Your geo contractor should be able to set this up for you. Like the auto radiator stop leak product. Well worth a try. May or may not be perminant.

Americal Leak Detection is a national company that specializes in finding leaks in many kinds of pipelines. We have used them on commercial GX applications and in our oil and gas partner company. About aa 90% success in finding leaks. I don't know how cost effective it is for residential but if they are in your area it is worth a call.

Unpressurized flow center is a band-aid. Fluid added to the flow center should be monitered to give you an idea of the magnitude of the loss but is an easy way to add fluid to the system.
Good Luck

 

Geothermal Loop "Fix-a-Leak"

Has anyone seen any indications of lower efficiency after using the Geothermal Loop "Fix-a-Leak" or any other side issues? My concern is that the "Fix-a-Leak" compound could also gather in corners and small spaces in the heat exchangers, thereby lowering efficiency. I have always heard that after putting fix a leak in a car's cooling system, that the stuff collects in all the corners of the engine block and creates "hot spots" within the engine.

Anybody tried the "Fix-a-Leak" and had it not work for them?

Thank you to all that have replied to my posts. I have been researching a lot, but I am just a homeowner with a problem geothermal system, I lack the invaluable experience and knowledge with these systems that many of you have.

 

Loop Conditioner

We have not seen any notable efficiency changes. Remember, this product is also a band-aid. There is a precipitate formed by the product that resembles a carbonate scale or the type of scale formed by the “Growing Rocks” children’s toy. It may or may not work on the leak in your system. We have not had any problems with pumps, impellers, valves, or heat pumps in the systems where this was used as a first solution. Similarly, we have not had any problems with the systems that had the product injected and it did not plug the leak. We have had several systems where the leak was cured for several months but had to add a second bottle later – also mixed results.

It’s a good first try.

 

After "Fix-a-Leak" fails.

To the contractors;

How often do you find loops that leak? Is it 1 in 10, 1 in 50, 1 in 100?

If you have used the "Fix-a-Leak" in the loop, and it hasn't worked, was is the next step that you take?

I would like to here fthe opinions from all the contractors our there. Thank you for your comments.

I have talked to American Leak Detection and they seemed to be very familar with finding and repairing leaks on horizontal loop installations, but after discussing my case with the sales representative, it seems like it could easily take $3000-$6000 to find the leak and repair the loop. The sales representative explained that they evacuate the fluid out of the entire loop, then pump helium or hydrogen (think it was helium) into the entire loop and use a detector to find the leak. If the loop goes under concrete like in my case, they may have to drill small holes in the concrete where they believe the leak may be. This seems like looking for a needle in a haystack, but the sales representative seemed confident they would find the leak if allowed to spend enough time on it.

I have a five-ton system, and I would seriously consider installing a new loop before spending this type of money with no gaurantees on how long it is going to take to find the leak. I am not the original owner of the house, so the company that installed my loop will not cover the problems I am having under warranty plus the loop is 12-13 years old.

 

I'm not a contractor, but I asked our installer about how he handles a leaky loop at the time of our installation.

If there was a leak, he said he would dig up our manifold and narrow down the leak to one of our three trenches. He said he would then dig a new trench next to the leaky one and install a new loop there. I don't know if this is a common approach or not.

 

In my experience, leaky loops are ~none-in a hundred.
Don't know history here or if 'fix-a-leak failed' you, but there is much more info needed to advise you.
J

 

I would dig up the manifold if you can. For two reasons.

1) this is the most likely place for the leak to be

2) then you can isolate the loop that is leaking.

3) once you know which loop is leaking, then you can decide whether to repair or replace.

4) the only times our loops leak ( we have 1000's installed ) are when the loop is damaged by other activity.

 

Leaking Loop

Try the Loop Conditioner first - it is reasonably simple to put into the loop. If it doesn't work and you can last to spring (and yout loop is staying above ~40F in cold weather) with small additions of fluid (antifreeze mix) then the advice from geome/palace is good. If you have to get into major repairs, you may want to upgrade to an new, energy star efficent, heat pump and take advantage of the 30% federal tax credit for GX systems. You may also want to check state and local incentives as well - go to dsire.org

Leaks on systems installed by trained contractors are rare but can happen with any system. We are a design engineering group and have designed and inspected (litterally) millions of installed vertical and horizontal feet of HDPE. Not counting the pipe's alergy to backhoes and gophers, we have seen very few installer related leaks. Half of those were due to assemby by untrained contractors and most from "do-it-yourself homeowners.

 

As other members have suggested, we would dig up the manifold, separate the individual horizontal loops and test each to determine which loop was leaking.

 

I do not like fix-a-flat either

I might try the band aide, I do not think the finding leaks r us quote will include repair once the leak is found.

Try find a pro here and ask about loop field replacement.

 

Reading the fine print on conditioner

"Do not use if a strainer is installed in system"

So I'm not sure what adverse effect this might have on a air and dirt eliminator. (assuming you have them)

 

Remove the strainer guts during the 24 hour initial circulating period and then replace. Clean as necessary. You may need to bump the fluid volume up a bit after replacing the strainer. If that is not practical, go back to digging up the field.

 

Same problem - needs recharged bi-weekly now. Here's my history... system is 19 years old, no problems until a few years ago it needed recharged, then the tech had to keep coming back more often, repairing bad PVC fittings and recharging, and finally, this past summer, discovered the return line PVC had a large droop. Obviously the line was subject to temperature over 200F, so system was running in cooling mode with no or low circulation. Replaced PVC, then had to replace the unit because of leak in the exchanger. Everything inside is new now, including pumps. The furnace company has installed a pressure switch on the line, so the system stops when pressure drops too low and unit goes to aux heat. The company says they have never seen a leaky loop except where someone dug into it. I'm hoping my leak is from the overheating and is just outside. I will be attaching a hose to keep pressure up (my January bill was 3X normal!). I might try stopleak. Any suggestions are very welcome!

 

Not sure how much you're willing to spend, but rather than a hose, you might consider an automated makeup system like this. You can have the proper mix in the makeup tank and spend little time monitoring it.
http://www.supplyhouse.com/Axiom-MF200-MF200-PRESSURE-PAL-Hydronic-Mini-System-Feeder-6-Gallon

 

Thanks. It's cheaper than a new ground loop. I'll keep it in mind as we think through this problem.