Michigan pump is making noise sounds like air

Discussion in 'Maintenance and Troubleshooting' started by Matthew Miska, Aug 22, 2017.

  1. Matthew Miska

    Matthew Miska New Member

    My WF geo loop was installed in 2003 single pump on a WF 4 ton unit. I noticed the loop pump making noise. No noticeable drips, unit is cooling the house.

    Loop static pressure is Zero, running it is 10 psi to the unit and 6psi back to to the horizontal closed loop.

    It is quiet for the first 2 minutes then air sounds start, not extremely loud but I notice the difference.
    Never worked on a Geo loop before please advise.
    Matthew
     
  2. arkie6

    arkie6 Member Forum Leader

    It sounds like you just need to add some water to your loop and bump up the static pressure to >20 psi to insure sufficient Net Positive Suction Head (NPSH) to prevent cavitation at the pump suction. As the unit runs in cooling mode, the loop temperature starts increasing the longer it runs which causes the plastic loop pipe to increase in temperature and expand in size which results in a drop in loop pressure which then causes the pump suction pressure to drop below the minimum NPSH which results in cavitation on the pump impellar which makes the noise you are hearing.

    Pump cavitation explained: https://blog.craneengineering.net/what-is-pump-cavitation

    If you have Pressure-Temperature (PT) ports where your loop pipes enter the geo unit, you can add water / raise pressure from a garden hose using a tool like this found on ebay: http://www.ebay.com/itm/GEOTHERMAL-...455990?hash=item3d44186af6:g:rLQAAOSwzXBZggql
     
  3. Matthew Miska

    Matthew Miska New Member

    Thank you , i can put that together, i will post results.
    Matt
     
  4. Matthew Miska

    Matthew Miska New Member

    should I consider adding any freeze protection?
    I know the loop has Environal anti freeze in it now. I am in Michigan
     
  5. arkie6

    arkie6 Member Forum Leader

    I doubt it is necessary. It will probably take less than a quart of water to pressurize the loop.
     
  6. Russ Lickteig

    Russ Lickteig New Member

    Anyone here had water level drop with a leak in the line? My Flowcenter (pumping station) water level is low. Had it filled yesterday for $425 big ones and today the level is low again. Called the guy who put the lines in the ground and they are going to come out and run a conditioner through the pipes to try and clog the leak. Wondering what the odds are that they can fix it???
     
  7. mtrentw

    mtrentw Member Industry Professional Forum Leader

    I had a very slow leak. Maybe a gallon a year. I put loop conditioner in three years ago and have not had a problem since.
     
  8. J Ali

    J Ali New Member

    Im sorry if this is an old post, Im scouring everything I can find to educate myself on this old system. We've had three different people out and Im not sure any of them actually knew what they were about. I have an older system without these PT ports but with short garden hoses coming off 2 of the 3 lines going to/or coming from pumps like they've been used to add water to the loops prior to us moving in 4 years ago. Pressure on this particular pump is up to 5psi when running and zero when off. Just had leak fixed 24 hours ago(small hole found at connection on bottom of 300foot loop) on pump number three cooling the upstairs. Company said this pump had only 5 psi when they were working on other one. Just coincidental? now the grinding sound seems to be coming from different area and zone to main living area not cooling or blowing much air. We have 3 vertical loops servicing three zones in house. Above problem seems to possibly be what we need? but how does one actually add water to the loop without PT ports but with the side ports where short hoses attached?
     
  9. mtrentw

    mtrentw Member Industry Professional Forum Leader

    To refill my pressurized system which had garden hose thread drain fitting I bought a pump up sprayer in garden section and a garden hose thread to barb fitting. Replaced sprayer wand with fht to barb adapter and one hose clamp.

    If environol (ethanol base) you could get a quart of cheap vodka cut 50/50 with water to maintain 20% ethanol.
     
  10. J Ali

    J Ali New Member

    I put one of these loop fill tools together. Turns out I actually do have PT ports. Newer comfortair heat controller units, just old suction pumps. I’ve added water via PT ports but seems to keep losing pressure. Is it possible that there’s air in the line? Introduced when they fixed the other loop? Seems they are all connected even though I have only two heat controller units but three closed vertical loops. Couldn't find a manifold. Can’t seem to figure how to purge the air without a flushcart.
     
  11. J Ali

    J Ali New Member

    Thanks for all the info and input! Really appreciate all the help.
     
  12. geoxne

    geoxne Active Member Forum Leader

    If it sounds like air than it is probably air. Whenever a loop system is opened for repair or leak, it must be purged of air before the system is placed back in service. More often than not this requires a purge cart and proper procedure especially with multiple units.

    In your case it sounds like there is air in your loops and moving around to different locations depending on what pumps are running.
     
  13. J Ali

    J Ali New Member

    Thanks geoxne. Any idea who would be best suited to do that, as far as type of company? Called “geothermal HVAC” company and they don’t work on “wells”, only the heat pumps, called a well and pump company and they don’t do geothermal wells or loops.
     

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