Geothermal not keeping up.......77F right now.

Discussion in 'Maintenance and Troubleshooting' started by delorean, Jun 18, 2012.

  1. delorean

    delorean New Member

    Geothermal not keeping up.....UPDATE: Not fixed, but new info.

    UPDATE: It seems I had it all backwards. STAGE 1 is where the intermittent problem is. If I restart the system, the Y1 call lights comes on, and only the blower fan comes on.....the A compressor never starts. Then when Y2 lights, the fan goes to 100% and the B compressor starts. It's running in stage 2, with only the second compressor.

    I can manually press the A-relay in and get compressor A to start, but as soon as I let go, it shuts off. If run leads from the B-relay and jump the A-relay, and it will close. So, it's not the relay--it's the power to the relay, or lack thereof.

    One of the other things that I have found, if I do a cold restart with the stage 2 (B-relay) disconnected, the A-relay will sometimes close and start the problematic stage 1. Then if I wait until the Y2 call light comes on and reconnect the B-relay, all works normally. That's how I have gotten through the 108F days here in St. Louis.

    Everything is working normally now, so I'm just trying to get as much info and ideas together so I can duplicate (if not explain) this to the tech next time.

    Thanks again for all the support.


    I've been having a few problems with my system the last few days. It's not keeping up with the 90F+ afternoons. The system runs nonstop from about noon until after midnight and it will be 75-78F when the thermostat is set at 70F.

    -St. Louis, MO
    -2500 sqft two story very well insulated & window tint
    -ClimateMaster with a two vertical closed loops.
    -The loop pressure is 50psi
    -The water temp going out to the loop is 80F
    -Coming back in from the loop is 74-75F
    -Cold air return temp is high 70s (ambient)
    -Air leaving the unit it's 66-67F
    -Clean filters, clean coil, good ducting.
    -Worked great last summer, and over the winter.
    -Both pumps are running, as is the desuperheater pump

    Now here's what made me think something is wrong.......the water in my buffer tank is in the 70s. Normally on hot days when this thing runs non-stop, the water in the buffer tank is 100-110F+.

    So what's up with this thing? Is the loop not circulating?
    Last edited: Jul 9, 2012
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Checking the flow rate through the unit and the gas pressures for your ewt is a good place to start in on diagnostics. The ewt vs. your gas pressure will list the units capacity at that place in time.

    Finding what is different from last year should tell all. Loop data and unit size would also help.

  3. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    This indicates the loop is circulating fine.

    This seems to be the problem.

    The air leaving the unit should be more like 50°F

    Someone who understands how to diagnose heat pumps will have to give some clues as to why yours is not working properly.
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Agree with DeWayne

    Airside temp split should be approx 20 degrees.

    This may be a case of loss of system charge

    That does not square with the low buffer tank temperature...low refrigerant charge causes higher compressor discharge gas temperature which should lead to higher, rather than lower buffer tank temperature.

    I'd want to be sure airside coil / filter isn't dirty, be reasonably certain of proper system airflow, make sure there is no icing, and then break out the gauge manifold.

    Probably will need a good local tech to dig into it
  5. delorean

    delorean New Member

    After messing with it some more, the second stage was not kicking in for some reason (or not enough.) I went into my VisionPro's settings and found the stage 1 & 2 were limted to cycling 3 times an hour on cooling (on autodiscover.) I kicked them both up to the max--6 time an hour. We'll see how it goes today.

    Once I did that, the temp dropped leaving the coil was around 58F. I am down in the basement a lot and I can always tell when this thing goes into second stage--thinking back the last few days, this thing was never in second stage.

    As for the desup, I have warm to hot water in the tank again. Does the desup only work on 2nd stage cooling?
  6. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    desup works both stages, you just get more output in 2nd stage
  7. delorean

    delorean New Member

    It's at 73F this afternoon......thermo is set at 71F. OAT is 94F.

    So, it's getting better but still not keeping up.
  8. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    How old is your system?

    Did it keep up last year?
  9. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I doubt the CPH setting has anything to do with capacity. Lower CPH allows slightly wider temperature swings between cycles when the system attains setpoint. If setpoint is more than 2 degrees below sensed temperature, system should be continuously operating in 2nd stage regardless of CPH.

    I think you had some issue locking the system completely out of 2nd stage. That would account for lack of capacity and reduced DSH / buffer performance.
  10. jrh

    jrh Member

    Forget about using your buffer tank temps to determine what is wrong with your system.

    Has your installer offered any diagnosis?

    I would agree that your cycles per hour should not have any effect if your unit is never reaching setpoint. The fact that adjusting them seemed to have help is making me think that the problem may be that the heat pump is not getting a proper call for O,Y1,Y2.
  11. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Late in the game here, but DT between entering and leaving water temperature on first seemed about normal which would suggest you are okay on the refrigerant side. DT of the air was not. Generally your air DT will be similar whether in first or second stage as lower blower speeds compensate for lower btu extraction.

    I think we definately need boots on the ground here.
  12. delorean

    delorean New Member

    UPDATE: Sorry to leave everyone hanging on worked for a while, then it didn't, then it worked, then it didn't. I did not really have anything definitive to post. But I do now!!

    The second stage was/is not kicking in. Thermostat is calling for 1&2 the whole time, but the A side never kicks on. So I manually engaged the relay and the second compressor kicked in right away.

    I let go of the relay, and it shuts off. So, hoping it was just a bad relay, I jumped it from the other side, and it worked. Not the relay.

    Then, like the other day when I messing around with it, all the sudden the relay kicked on and it went to stage 1 & 2 by itself. Shut it down, wait for the delay, thermo calls for 1&2, and only 1 compressor again.

    So, where do I go from here? Bad circuit board maybe? What else can stop the low voltage from energizing that relay?
  13. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    ......thermostat, pressure switch, limit switch..........
    lots of things. Did we establish we have 24v to Y2 at the board?
  14. delorean

    delorean New Member

    The yellow wire off of Y2 runs to the B compressor, and that's the one that's always on (calling for Stage 1 or 2)

    The yellow coming off of Y1 is the one running to the A compressor (the intermittant one.)

    BTW, sorry for not posting this sooner:

    Decoder for VT060GSSSLTDDSE
    Series 2 Digits VT CLM Vert. High Eff. Ultra Classic Heat Pump
    Size 3 Digits 060 060 MBtuh Nominal Cooling Capacity
    VOLTAGEG208 V Coml/230 V Res,1 Ph, 60 Hz
    Agency Approvals S Safety Agency Approved-US/Canada Markets
    Controls 2 Digits SS Standard Electro-Mechanical Controls
    Airflow/filter CLM 2 Digits LT Left Top / 1 inch
    Class, Cabinet, Freezestat D Distributor Class, Painted, 21 FS
    CLM Condenser D Copper w/ Hot Water Generator (HWG)
    Standard or Special Rev Level S Standard Unit
    CLM Revision Level E Rev E
    Last edited: Jun 27, 2012
  15. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    OK- the next question is have we established a constant 24v to Y1 (which means compressor first stage btw)?
  16. delorean

    delorean New Member

    I cannot really complain about this, but......

    Now it's working--and that's a good thing because it hit 108F in St. Louis today. Hopefully it keeps working over the next week as highs are not supposed to get below 100F until after the holiday.

    I'll report back if it stops working again.

    Thanks a million for all the help.
  17. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Is it possible that Y1 and Y2 are reversed?

    Every two stage system I deal with maintains Y1 during Y2 calls. In other words, in order for the system to go into high stage, Y1 and Y2 must both be energized with 24 Vac.
  18. delorean

    delorean New Member

    It wasn't working again today......

    I pulled the cover off and ready to attack it with my multimeter. At some point on tracing wires, I must have knocked something because stage two kicked in.

    I'm not sure what I'm looking at, so maybe someone can ID the part I manipulated right before it kicked back in. This was a round sensor about one inch in diameter. It was contoured to fit to a copper pipe located near (but not connected to) the desuperheater. It had two blue wires; and two brown wires running to it (one of which was unused--terminated in a wire nut.)

    If it happens again, maybe I can narrow it down some more. I've had a tech out here twice and both times it been working fine. I don't think he believes me when I tell the second stage is not running.
    Last edited: Jun 30, 2012
  19. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Okay first- if Y1 is not activated, that is stage 1. We need to make sure we discuss the same thing.
    I recommend you disconnect ALL power to the geo unit then trace all wires to there connections and make sure all are tight. Restore operation.

    If problem occurs again, wiring problems are often easy to recreate by wiggling wires.
    Intermittant problems are hardest for a tech to sort out (I can't "fix" a working appliance), so make sure you show him what happened if he comes back.
  20. delorean

    delorean New Member

    I am confused.....(more than before.)

    When it's not keeping up, the Y1 and Y2 call lights are both illuminated. If I manually trigger stage 1 cooling from the thermostat Y1 illuminates; trigger stage 2 cooling and Y1 and Y2 both illuminate.

    If Y1 is lit the B-compressor is running

    If Y1 & Y2 are lit, both A & B compressors are running when it's working......(If it's acting up, just B runs until I manually engage the A relay).

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