Michigan New Geo-Flo GPM circulation pump noise

Discussion in 'Maintenance and Troubleshooting' started by d_rek, Dec 5, 2016.

  1. d_rek

    d_rek Member

    Hi everyone,

    First: I've read a ton of information on this forum and it helped me greatly in deciding to go with geo for my new home. Thanks for the great community!

    I had a new home built in the summer this year. Decided to go with geo for a number of reasons. New system was sized and installed without issue: Bosch Greensource CDi series heat pump, Geo-Flo GPM model 1333-1169 circulation pump setup with two pumps (GPM-2 setup) with a closed ground loop.

    The unit was running at lower temp throughout the month of October (65F), so it wasn't kicking on very frequently. I did a number of projects at the house before we moved in but didn't notice any noise we are currently experiencing.

    After we started living there (since nov. 20th) I noticed the circulation pump was very noisy - lots of sputtering and occasional mechanical squealing - like a high pitched whine - sounds. The heat pump itself is quiet with the exception of the blower. The geo lines are also very quiet, and I cannot detect any noise coming from them (I've read that gurgling or other noise can be air in the lines).

    The noise seems to be coming from one or both of the circulation pump motors, and seems to be getting worse as we are now living in the home and running the furnace more frequently and at a higher temp (70-73F - that pesky wife likes to bump it when i'm not looking).

    I've had the HVAC installer out once now and he made some adjustments to both the backup water heater (for heat recovery) and the circulation pump and said if the noise persisted he would probably have to order a new circulation pump. He said the noise was coming from the pump, and not the lines, so he didn't flush the lines as I initially thought it was the lines making the noise. I called him this morning and said he was going to have to order a new circulation pump.

    So now I have the following questions:
    • Opinion: Do you think it's possible I got a bad circulation pump or pump motor? Or was it an installation issue?
    • What do you think the underlying issue could be with the pump and what could be causing the noise? I've read through the Geo-Flo literature and they identify a number of items that could be causing the noise.
    • Is it common for circulation pumps to have issues out of the box? Seems like a brand new pump shouldn't be making any noise, unless it was installed incorrectly.
    The good news is that the system is working great and keeping the climate very comfortable in the home, though I guess i'm really disappointed that for a $20k+ geo system i'm experiencing noise issues out of the gate. To contrast my grandmother has a geo system - Waterfurnace circulation pump, not sure of the heat pump brand - that is going on 25 years old that with the exception of the blower on the furnace you would never even know it's running. It also only has a single motor on the pump.


    Here are some picture of the system:



  2. d_rek

    d_rek Member


    New circulation pump very noisy; sputtering sounds and mechanical squealing coming from one or both of pump motors.
    • Opinion: Do you think it's possible I got a bad circulation pump or pump motor? Or was it an installation issue?
    • What do you think the underlying issue could be with the pump and what could be causing the noise? I've read through the Geo-Flo literature and they identify a number of items that could be causing the noise.
    • Is it common for circulation pumps to have issues out of the box? Seems like a brand new pump shouldn't be making any noise, unless it was installed incorrectly.

    Sorry here is some of the information from the troubleshooting checklist. I can probably capture temps myself when I get home:

    1) Where you live - Michigan
    2) Heat loss/gain calculations for your home - n/a but the installer said the system was sized correctly. I'll have to use one of the calculators to provide this info.
    3) Brand, size (model) and type of heat pump - Bosch Greensource GDi heat pump, Geo-Flo Flo-Link GPM-2 1333-1169 circulation pump
    4) Type of loop field (open/closed/vertical/horizontal) size and design parameters - Closed. Approx size: 100ft (W), 40ft (H), 16ft below grade (D)
    5) Average cost/Kwh of electricity and consumption - n/a
    6) Entering and leaving air temperatures (EAT, LAT) measured immediately upstream and downstream of the heat pump - n/a
    7) Entering and leaving water temperatures (EWT, LWT) measured at the heat pump(s) - n/a
    8) Percent of load to be covered by geo and balance point - n/a
    9) Installers assessment of your systems operation. - Bad circulation pump motor(s)
    10) Projected operating costs, actual operating cost and previous heating and cooling costs - n/a
  3. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Air in the system. It does this to pumps. Or a small rock or such. I'll let you judge whether that is an installation issue.
  4. d_rek

    d_rek Member

    If it is air or some other debris in the system I would most definitely judge it to be an installation issue, as I would have expected the lines to be bled of air and debris cleared as part of the install.

    If we're tossing judgements around, would you deem this installer competent based on the info above and the noisy pump? There have been a few red flags already with this installer, though since the system seemed to be working well I was willing to forgive them.
  5. d_rek

    d_rek Member

  6. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Hi and welcome!
    You have a failing circ pump. Wet rotor pumps like the ones you have demand anal attention to purging-cleaning of all debris from system prior to running. Replace the pump now, and ensure the contractor has some type of filtration on the purging set up to catch and remove, sand, dirt, pipe burs, ect.
  7. d_rek

    d_rek Member

    Thank you for the reply! I feared that was the case. I have given this installer the benefit of the doubt thus far but now I will need to play bad cop. I have a wife and two young children at home and temps are starting to dip so we can't be without HVAC for any extended period of time.

    Hypothetical: If this was your system what are steps you would take to resolve the issue? I want to be be armed with as much info as possible. Thanks again!
  8. Dinnerbellmel

    Dinnerbellmel New Member

    I don't understand the issue. Based on your first post, the installer mentioned replacement of the bad pump(s) as a likely outcome if the noise doesn't improve. Pumps arent that expensive where the installer will ruin this set-up (and their reputation.) Address it with them and follow waterpirate's advice above. I would also question what went wrong and how they can ensure your system will be humming after the fix.

    BTW, I built a new home too with geo and we had a circulation pump (Grundfos also) replaced in the first month or two as well. We've had no issues since (knock on wood.)

    I'm curious why your basement isn't insulated or if the insulation is on the outside of the house?
  9. d_rek

    d_rek Member

    It's an unfinished basement. There is 2" foam insulation on exterior of foundation which I think is code now. The rim joists have also been sealed with caulk and rigid foam per my request, but the GC said they would have done it anyway to satisfy code. The basement is fairly comfortable for a basement, though I have all the ductwork shut down there.

    Sorry to hear your pump failed soon too. Is this a common issue? I am not terribly impressed with this installer thus far. Hopefully he makes it right.
  10. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Your grandmother's installer 25 years ago had more wisdom than your installer.
    Your (2) 26-116 pumps use 400 watts each, 800 watts total. In my opinion, 26-116 pumps do not belong on a geo system. What size heat pump do you have? Model number?

    A pump can be defective, that is not the issue, parts can break and can be replaced. But usually geo systems should be designed to energy efficient.

    If this is my house I would check the pressure drop and flow, you are likely over pumping right now, and throw out the entire flow center. Do the math, wasting all that pumping energy for the next 25 years will cost you thousands of $$$....
  11. Dinnerbellmel

    Dinnerbellmel New Member

    To follow-up on Doc's post, our particular house has 26-99 pumps. I don't have the specs but they use close to half the energy with only a marginal decrease in flow compared to 26-116 pumps. I'm sure I will be corrected if the above is incorrect...
  12. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    You are correct. In the last 4 years I have not installed a single system with more than a single 26-99 pump. Not more is needed if the loop field is designed correctly with low pressure drop.
  13. d_rek

    d_rek Member

    How do I know if my field was designed incorrectly or not? I know the approx dimensions but that's about it.

    I left this all in the hands of my GC who, admittedly wasn't knowledgeable about geo systems, but ensured it would be designed and installed properly by a reputable installer. It is seeming like that is no longer the case.

    Are there other questions I need to be asking both the GC and the installer?
  14. d_rek

    d_rek Member

    The installer mentioned they usually don't use two pumps but didn't elaborate.

    The heat pump is a Bosch Greensource GDi sm036. Here is a picture of the sticker on the unit.

    https://www.dropbox.com/s/2jvi7w0eydyyf92/File Dec 06, 11 30 47 AM.jpeg?dl=0
  15. d_rek

    d_rek Member

  16. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    It is only a small 3 ton heat pump, rated for 9 gpm flow. I sometimes feel bad putting a single 26-99 on 3 ton since they use 230 watts and are over pumping. You are using 800 watts. Have them trow out the flow center, and have them put in a flow center with a single, much slower pump. I am not in favor of bashing other contractors, but this is bad.
    Ask them for the commissioning sheet with the flow and the pressure drop documented, and details about the loop field. How many circuits, how long is each circuit, what is the pipe diameter, how long is the header pipe and its diameter coming into the basement. 3000 hours run time multiplied by 500 watts are 1500 kwh per year more. For nothing.
  17. d_rek

    d_rek Member

    Thank you for the detailed reply. I will request that Information from the installer. I called another local company and they said I could probably just disconnect the bad pump for the time being, but also mentioned that particular pump was oversized for my system. What they said seems to align closely to the recommendations received here. I will report back after I speak to the installer again.
  18. d_rek

    d_rek Member


    I've called the installer twice and they have still not been out to address the issue.

    Ironically, the noise has subsided. The pump appears to be running so I am not sure what this means, though it still occasionally makes sputtering noises.

    I did speak to them they did order a replacement pump, though claimed they were busy helping people without heat(cry me a river). I also asked about the electric use and the installer claimed this pump would only draw .7amps when running, or 160 watts. I have no way to verify this though, and was going to reach out to manufacturer for more info.

    After the installer replaces the pump I am washing my hands of them. Have not had a good experience at all with them.
  19. d_rek

    d_rek Member

    The installer was wrong regarding the amp draw on that specific pump model. Here is the submittal data for those pumps. He was right about the amp draw but that is for the smaller pump.


  20. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    We measure around 1 amp for the 26-99, and around 1.9 amps for the 26-116. Both on 230 volts. No matter how you twist it, the 26-116s should not be on any geo system. Especially not on a 3 ton system needing only 9 gpm.
    Adding insult to injury is then putting (2) 26-116 on a 3 ton system.

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