Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Typical pressure of ground loop

Options
zepfan
zepfan Member Posts: 398
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

Comments

  • hot_rod
    hot_rod Member Posts: 22,258
    Options
    Can you isolate the loops and pressure test them. The tube should hold 30 psi or more.
    Is there a manifold somewhere?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,110
    Options
    What is the Geo  loop material? Mad Dog 🐕 
  • zepfan
    zepfan Member Posts: 398
    Options
    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
    Jamie Hall Member Posts: 23,439
    Options
    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.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2
  • ethicalpaul
    ethicalpaul Member Posts: 5,735
    Options
    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
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    Mad Dog_2
  • hot_rod
    hot_rod Member Posts: 22,258
    Options
    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
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2
  • zepfan
    zepfan Member Posts: 398
    Options
    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
    Mad Dog_2
  • hot_rod
    hot_rod Member Posts: 22,258
    Options
    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.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    zepfanMad Dog_2
  • zepfan
    zepfan Member Posts: 398
    Options
    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
    pecmsg Member Posts: 4,883
    Options
    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!
    zepfanMad Dog_2
  • leonz
    leonz Member Posts: 1,159
    Options
    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

    =================================================================

    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.




    DerheatmeisterMad Dog_2
  • coby
    coby Member Posts: 17
    Options
    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
    Jamie Hall Member Posts: 23,439
    Options
    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.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    zepfan
  • hot_rod
    hot_rod Member Posts: 22,258
    Options
    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
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream