New York Short Cycling?

Discussion in 'Maintenance and Troubleshooting' started by Steve Toorongian, Mar 17, 2016.

  1. Steve Toorongian

    Steve Toorongian New Member

    Anyone have any thoughts on why my Geo system "short cycles" in the Spring and Fall when the outside temperatures are transitioning? By short cycling I mean the compressor comes on and runs for a very short time < 5 min and then shuts off. I doesn't happen all the time and the system seems to be running fine all winter. Its just when there is a warmish day but the temp drops in the evening or sometimes in the morning. The secondary loop temp (radiant) has dropped to ambient in most of these cases so a couple minute compressor run does nothing but wear the motor and start capacitor. I have an outdoor reset controller to throttle the water temp based on the outdoor temp. I'll be happy to give more specifics on the system if needed. I just was wondering if this implicates any obvious problems to knowledgeable pros. Thanks for any and all help!
     
  2. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    less heating needs, the capacity is high versus the heating need in warmer weather, thus the thermostat gets satisfied quicker. Variable speed heat pump mitigate that problem by reducing their capacity. Water-Water heat pump use buffer tanks and the thermal inertia to reduce short cycling. The fact that you have an outdoor reset speaks for your installer. Nothing you can do with it. Some manufacturers are developing variable speed technology for w-w applications.

    In other words it is normal for the current state of the technology.
     
  3. Steve Toorongian

    Steve Toorongian New Member

    Thanks for your reply. I do indeed have a large buffer tank. I just don't understand how a 5 min run time on the compressor does much of anything at all much less satisfy the demand from a thermostat in the house. Or are you speaking of the thermostat in the buffer tank? Even there its hard to believe such a short run does anything to the water temp at all. Thanks!
     
  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    You can increase the temperature differential to allow it to run longer.
     
  5. Steve Toorongian

    Steve Toorongian New Member

    I guess I see the dilemma now. More temp differential means burning power for no other reason than to satisfy a setpoint. I guess I'm stuck unless I could retrofit a variable speed motor into the existing compressor if that would work. Hopefully I'm not in the market for a new Geo Heat pump for a while so I will stand pat. Thanks anyhow.
     
  6. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Not quite. It increases the run time of the heat pump by allowing for a larger temperature swing in the buffer tank.
     
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Listen to what Chris is telling you.
     
  8. geoxne

    geoxne Active Member Forum Leader

    Tips above will help. A 5 minute run is not short cycling. 6 or more starts per hour is short cycling.
     

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