Ohio Loop pressure rising

Discussion in 'Maintenance and Troubleshooting' started by geo_time, Mar 12, 2015.

  1. geo_time

    geo_time New Member

    I have a system that is slowly rising the loop psi upwards of 150 psi. It has blown the hoses off of the system. It is doing so in heating mode. I thought it was from the coax leaking into the loop, but have proven this not to be the case. It is a pressurized flow center with 2 pumps. When I disconnect the water in pump the pressure build-up seems to stop. Any thoughts? These circulating pumps cannot build up that kind of pressures. Any input would be great. Thanks
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Lots of thoughts in my head. Lots of questions I could ask. But I'll go with a gut.

    There is a blockage between the two pumps on the heat pump side.
     
  3. geo_time

    geo_time New Member

    I have re-flushed the loop field. I have replaced the hoses from the flow center to the heat pump. I didn't see any signs of any blockage. The pressure slowly builds up over run time, then slowly drops when the unit shuts down. I found one other person dealing with this issue in the forums. Waterfurnace tech says he has heard of this problem before but doesn't know the cause. It seems to be a rare case. I am at a loss. Eng. at willo circ pumps tells me the pumps can't produce these pressures. Says I need to be looking for a heat source. Pumps are cool. I want to get to the bottom of this one badly.
     
  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Ice can cause these pressures.
     
  5. heatoldhome

    heatoldhome Geo Student Forum Leader

    Expansion tank in this loop??
     
  6. geo_time

    geo_time New Member

    No expansion tank. I install closed loop systems for a living .Vertical/horizontal drilling. I have never put an expansion tank in as a part of my loop field. Why would you do this? I am asking just to learn what other people are doing. It would balance out pressure yes but I don't see the need. This particular case is a system we did not install. My fear is that the piping was not deep enough for this severe winter in ohio, and the pipes have froze. I have to believe that the system has been compromised. I was hoping that someone here in these forums might have encountered this problem before. It is looking like nobody has. Any input would be great.
     
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Is the loop freeze protected? How low?

    Is it a push/pull flow center?

    Could you be loosing refrigerant into the loop?

    Where in Cleveland are you located?

    How do you measure the increase in pressure?

    Mark
     
  8. geo_time

    geo_time New Member

    Loop was existing. It had been re flushed this year. I re flushed and added a gallon of methanol. I can smell the mixture and can tell it is methanol. So I believe it should be well enough freeze protected. It is a push pull flow center. There is not refrigerant getting into the loop. I am sure of that. The psi increase is measured with a pressure gauge in the p/t ports. I"m thinking it might be the viscosity of the water. Could be turning to slush. Hard to say. This is the problem with dealing with loops that others installed. Who knows what they did.
     
  9. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Pull a sample of the loop fluid and put it in your freezer with a thermometer.
     
  10. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    can use hydrometer or put in freezer/thermometer, to be sure of freeze point instead of the "smell test". We have had ice form in the coax before, on more than one occasion we did not install. we flushed the entire loop and started from scratch with all new methanol as we were not positive on initial install. I believe I actually received a "bad" 55-gallon drum of methanol this past year, so even though our data showed we were protected, it did not perform as it should have, so started all new. Put unit in cooling and see what happens to pressure.
     
  11. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I must have gotten that "bad" drum, too! Hydrometer showed the correct percentage, but the water was freezing.
     
  12. Keith Walters

    Keith Walters New Member

    I'm the homeowner in question that had the above issues last year. If not, dead on with the issues I had. Anyway, we installed n expansion tank (or open cylinder next to the furnace, etc) so I no longer have pressure building however I do have water building and overflowing a bit outside of the tank , not a big deal , but more importantly I have ice forming on hose portlets (can't recall exact name) and the furnace runs constantly when temp drops below 20 degrees. It's 2,300 square ft home with 4 150 ft verticle loops, or 600 in total. Maybe the loop field is " undersized" and the system is overcompensation and I need more loop?
     
  13. arkie6

    arkie6 Active Member Forum Leader

    Ice forming on the outside of the Pressure-Temperature (PT) ports isn't an issue in heating mode if the system is sized appropriately for sub-freezing loop temperatures and the loop water is properly freeze protected. Is the ice forming on both the water inlet and outlet ports?

    The unit running constantly when the temp drops below 20 degrees may not be an issue either. Where are you located? Do you know your design heat load? Do you know the low temperature assumed when your unit was sized? If the unit is operating near the design temperature, then it would be expected to operate continuously or nearly so. What size unit do you have? Single stage or two stage or variable speed? Variable or multi-stage units will often operate continuously when conditions warrant. Do you have auxiliary heat strips installed? If so, are they turning on during the very low temperatures? Again, this may not be an issue either if your system design temperature is near 20 degrees.
     
  14. Keith Walters

    Keith Walters New Member

    Ice just on the outlet port. I'm located in Cleveland and temps this week have been sub 20's. I have a 4 ton unit (I believe), it's a 2 stage unit but don't know some of the other "specs" that you reference. Aux does kick on but seems like only for a brief period when temps below 15 or so. Also, after posting this, I spoke with another Geo expert and our thinking is that the loop field may be a bit undersized, but that by and large, as you say, everything is mostly working correctly. I'm overly sensitive this heating season given the issues I had last winter (i.e. pressure building and hoses blowing when I used to have a pressurized system). Again, have since installed an " canister' next to the unit, which among other things, relieved the pressure situation so now I am just wondering if the system is operating efficiently overall. Thank you for getting back to me so quickly! More to follow as I monitor the unit this month.
     
  15. arkie6

    arkie6 Active Member Forum Leader

  16. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    There is a reason that the loop side pressurized. You have reduced the symptoms, but not cured the illness. I can come look.

    Mark
     
  17. Keith Walters

    Keith Walters New Member

    Mark, my cell is 330-990-4100 and I live in Cleveland Heights OH. Any chance you can at least give me a call and then potentially check out the system? Seems to be working OK but I have a couple of questions - things that don't necessarily make sense. Thanks
     

Share This Page