Typical pressure of ground loop

zepfan

Is there anyway to tell what the approximate loop pressure should be on a geothermal system? This is with the pumps in the flow center off. The system in question I am not sure if it is a vertical, or horizontal loop, but I have worked on the equipment connected to it for the past 15 years and have never had to add fluid to it. I have had two pumps fail this year, and another one that is starting to become noisy. My fear is that the loop may have developed a leak in it. thanks to all

hot_rod

Can you isolate the loops and pressure test them. The tube should hold 30 psi or more.
Is there a manifold somewhere?

Mad Dog_2

What is the Geo  loop material? Mad Dog 🐕 

zepfan

There is no manifold, the loop comes directly from the ground to a flow center. The piping is schedule 40 pvc, the piping that comes out of the ground is a flexible black material that adapts to pvc. Thanks for the

Jamie Hall

There should be very little pressure in a ground loop, although it should be slightly positive. A few pounds per square inch at the circulating pump return is ample.

ethicalpaul

Thanks for that answer, Jamie, I was always curious about that too, because with mine I chose a loop pump that was open to the atmosphere so I didn't have to deal with that whole "charging cart" stuff

hot_rod

Do you know what type of fluid us in the system? You should not have any type of glycol in PVC

GEO fluids are some times a brine solution in plastic pipe. Or plain water if all the piping us out if freeze hazard

zepfan

I believe the fluid is some type of brime or alcohol solution. The fluid is clear, and we had it tested and it definitely not glycol thanks for responding

hot_rod

Is there a pressure gauge on the system now? A accurate one. Somehow you need to get it pressurized to determine if there is a leak. If nothing obvious in the room, it is underground. Somewhere there is a manifold, I doubt it is just a single loop based on that pipe size, and dual high head pumps?

Any history on who or how it was installed, wells or trenches?

You need a starting point, pressure test, then excavating if there is no info available for locating the loop ends.

zepfan

thanks for the responses. Currently there are no gauges. Each unit does have a pete's plugs on them and I was going to attach a gauge there just to get a reading. I have asked the homeowner about the history of the loop and unfortunately they do not have any information. The whole system was done in 2003

pecmsg

zepfan said:

Is there anyway to tell what the approximate loop pressure should be on a geothermal system? This is with the pumps in the flow center off. The system in question I am not sure if it is a vertical, or horizontal loop, but I have worked on the equipment connected to it for the past 15 years and have never had to add fluid to it. I have had two pumps fail this year, and another one that is starting to become noisy. My fear is that the loop may have developed a leak in it. thanks to all

If you're measuring at ground level than standing pressure of "0" is possible.

Get gauges on the system. A small amount of air to build pressure 5#'s and see if it holds!

leonz

zepfan said:

Is there anyway to tell what the approximate loop pressure should be on a geothermal system? This is with the pumps in the flow center off. The system in question I am not sure if it is a vertical, or horizontal loop, but I have worked on the equipment connected to it for the past 15 years and have never had to add fluid to it. I have had two pumps fail this year, and another one that is starting to become noisy. My fear is that the loop may have developed a leak in it. thanks to all

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The best way would be to visit the local building inspector first to dig out any permits to find out what you can about the place.

If you already know the acreage etc., you can hire a pipe locating service to find the pipe runs or well if any after that.

coby

What you showing is a pressurized system. the system should be pressurized to 30 to 60 psi for best results. You need that pressure to create turbulence. A non pressurized system is o until the pumps start.

Jamie Hall

Note that while the system static pressure may be one thing,, the pump -- just like a heating circulator -- is only working against the head loss in the loop, which may be much less than the static pressure.

hot_rod

Its common to find high head circs in loop fields, so you want some static pressure to prevent cavitation

Typical 10-12 psi as you see in hydronics us adequate. If you increase pressure, assure the expansion tank pressure matches and that the tank has enough capacity 

Since loop temperature can drop below the fill water temperature, it wise to lower expansion tank 2 psi below fill to allow some fluid to enter the tank