Ontario 5 ton Geo running 24/7

Discussion in 'Maintenance and Troubleshooting' started by Maurice Sabourin, Oct 21, 2015.

  1. mrrxtech

    mrrxtech Member

    jk96,
    I didn't realize you had a zoned water to water geothermal heat pump. I was thinking you had one thermostat with a water to air geothermal which is why I suggested adding load. If the Unit ran for under 1/5th of the time period monitored, then I would say it is doing a nice job of saving you money, compared to the 24/7 run time Maurice is experiencing. Ouch!

    I worked in a building in the south that had an oversized AC system, so the "geniuses" I worked for turned on the ceiling tile heaters to provide a load for the AC, while it was 100 degrees outside. The power source on site was 2 860 MW units so electric cost wasn't considered. Personally I would have called McQuay back to fix the problem at the refrigeration units, but I wasn't in charge.

    Having the capability of adding a 3 degree band or swing, is a great feature to have on a thermostat. My Trane thermostat is the same model I used in the 70s on a split unit heat pump when I lived in the South. It's a 7 day programmable XT500 Taystat, digital yet simple and reliable.
    The house has to be at set point. If temperature drops 1 degree, the Unit starts up. At one point I considered going back to a mercury switch heat pump thermostat for the adjustable dead band capability.

    The newer model Trane XT500c (80's technology) used on the Carrier unit, has a programmable dead band feature which must have been programmed into a Programmable Read Only Memory chip since there are no mechanical adjustments in the thermostat . The Trane help center recently asked me why I didn't buy the latest technology for the Carrier unit. I told her then I wouldn't be having all of this fun trying to trouble shoot the unit. I use old thermostats for the same reason I drive vehicles from the 90s, they are relatively cheap, reliable and easy to work on/maintain.
     
  2. Maurice Sabourin

    Maurice Sabourin Newbie but learning quicly...

    l
    The second flow center was installed soon after the original installation. they were not happy with the numbers coming out i guess... i did not know much about it then, i still have the pump they originally used.

    Right now... i am starting to second guess myself...
    As far as i remember, i used to wake at night when the 5 ton would kick in, and i remember listening to it shut off after a 35 minute run.
    And i remember my wife telling the her studio (2 ton) was old and she could not increase the temperature, (I keep the aux breakers off when i am at the house)
    So the 2 ton never worked to my satisfaction... it cant keep up...

    the whole system is badly designed i am afraid...
     
  3. mrrxtech

    mrrxtech Member

    Maurice,
    If you subtract out the cost of the 2 geothermal units, flow centers, installed geothermal pipe, hot water heating, labor for installation of the equipment, and loop, your loss is actually much lower.
    With some low cost modifications later (deleting elbows, adding a surge or return volume with air removal), and getting the current installation running as when installed, you should still recover the cost in a reasonable time and begin to save money. All is not lost.

    Let me know what you find on the 5 ton unit Y1 signal Trouble Shooting as I described above. If you were correct in what you originally told us about the compressor running when the thermostat was satisfied, this is that 2nd problem that I have been talking about.
     
  4. geoxne

    geoxne Active Member Forum Leader

    You are chasing a red herring.
    If the HP was "stuck on" at some point the house would over heat at least in low load conditions. That is not a symptom here.
     
  5. mrrxtech

    mrrxtech Member

    The name of this thread is "5 Ton Geo Running 24/7".
    Maurice described going below set point, thermostat satisfied, and the 5 Ton continued to run.
    I'd like to know if he is mistaking a Lock Out where the fan only runs with a compressor issue. Maurice said based on power use the compressor and fan are running 24/7.
    Looking at the Y1 signal status and compressor contactor should clear up this confusion, or identify an additional problem.
     
  6. Maurice Sabourin

    Maurice Sabourin Newbie but learning quicly...

    I am sorry mrrxtech, and thank you for your insight.

    I dont think i ever said the 5 ton continued to run after i turn down the thermostat...

    the 5 ton continues to run after call temp is reached, the temperaure stays at call temp. if i increase the call temp by one degree the room temp will rise by one degree and the 5 ton will continue to run, but the room temp will stay at call temp.
    if i turn down the thermostat by one degree the unit will shut down, the same if i light the fireplace, if i increase the room temperature the unit will eventually shut down...

    i am sure we can eliminate thermostat and stuck contacts as a source of the problem.
     
  7. mrrxtech

    mrrxtech Member

    Maurice,
    I mistook the above, the title, replacing thermostats, high electric bills indicating the fan and compressor were running, as having a problem with the 5 ton unit, as well as a loop problem.

    My error. should have said: When the room temperature reaches or goes above thermostat setting the unit continues to run.

    How can your 5 ton unit run 24/7 but also work as it should?
     
    Last edited: Mar 5, 2016
  8. jk96

    jk96 Member

    I have two water to air units
     
  9. Maurice Sabourin

    Maurice Sabourin Newbie but learning quicly...

    mrrxtech,
    my 5 ton is running 24/7 even when the outside temp is 30f. it runs continuously except when i decrease the call temp or increase the room temperature with the fireplace.

    we have tried 4 different thermostats, we have checked and cleaned the filters. we have checked the flow centers and they are running as they should.
     
  10. Maurice Sabourin

    Maurice Sabourin Newbie but learning quicly...

    Today....
    Right now the outside temperature is 40f, the 5 ton as been working all night and all day, cycling between stage 2 and stage 2.
    the 2 ton as been running all day as well.

    the loop is in the pond more then 300' from the foundation, and the loop is 4 x "hyper loops". According to quote papers i found. the original design was to be a 7 ton Trane T2GX series. I cant remember why we did not go with that option, possibly because of the complex duct work to make it work.

    A pinched loop line may be very possible, i was not very impressed when they just buried the lines on top of jagged rocks, no sand under or on top...
     
  11. mrrxtech

    mrrxtech Member

    Maurice,
    Humor me. Go put your hand on each of the 4 pump motors while they are running. Memorize what each pump feels like, temperature, vibration, any flow noises. All 4 pumps should feel the same, except the return flowpath pumps will be colder due to the colder water.

    If you are going to have a system that you maintain, get to know the feel of it. We did this in Multi Billion dollar power stations, so I would recommend doing this in your home. I check my pumps every so often and they always feel the same. The day one feels different, a problem will follow.
     
  12. Maurice Sabourin

    Maurice Sabourin Newbie but learning quicly...

    I have and they are all working. I use this same technique with my vehicles. I know something is wrong by the feel of it.
    the pumps are working.
     
  13. mrrxtech

    mrrxtech Member

    You mentioned an antifreeze/loop leak, you have an air bubble in the system where the antifreeze use to be. That would reduce flow in the loop at an air collection high point.

    If the leak continues the units will shut down on cold Hx water temperature, like I had on the Carrier unit when the flow was too low. I got an FP1 failure.

    Got to go update the post I made, since the Thermistor is working correctly on the waters side HX low temp FP 1
     
  14. Maurice Sabourin

    Maurice Sabourin Newbie but learning quicly...

    The leak started after the problem started. The leak as been repaired and the loop was purged of air.
     
  15. mrrxtech

    mrrxtech Member

    I don't remember a discussion about Antifreeze, how much is in the loop, and to what temperature the loop is protected to. Ice formation would cause a problem in closed loop. I have a -20 solution from my memory that I checked with a hydrometer. I added a small amount of water to my loop, then later added a stronger batch of antifreeze mix to make up for the dilution I may have caused on the first addition from a water hose with pure water only in it.
     
  16. mrrxtech

    mrrxtech Member

    Maurice,

    From the above, the 5 ton is able to add just enough BTUs to your house to make up for losses using Stage 1 and cycling Stage 2. The outside temperature is mild for a winter temperature. If it were colder outside, I would expect the house to be below the thermostat set point running in Stage 2 continuously.

    If this were my 2 stage Carrier Unit it would run in Stage 2 until thermostat setting was reached, then shut down. I wouldn't expect Stage 2 to deenergize leaving the unit running in stage 1. This must be an anticipatory temperature control that I'm not familiar with.

    When the Unit was running properly, did the compressor shut off while in Stage 2 when the room temperature was met, or did it down shift to Stage 1 and continue running?
     
  17. mrrxtech

    mrrxtech Member

    Maurice,

    More Anitfreeze Discussion: If the loop water is close to the freeze temperature, as the water enters a 90 degree elbow the pressure drops which could turn the water to a slush mixture. This would effect flow in the loop.

    Return Air: Do you have a way to inspect all return air flow paths for anything that might reduce return air flow?
    I know of owners who have return air grates that hide a filter which acts as a pre-filter for the geothermal unit return air filter.
    I realize that if you had pre-filters, that the problem you are having would have shown up in the first year of operation.
    The blockage in the return air path is more plausible.

    If you assume the loop piping has not changed, due to the thickness of geothermal PVC (no pinched pipe or pond PVC heat exchanger shift), the flow center pumps are working correctly, the 2 Units have no new faults added by the card change out or thermostat changes, the return air paths have not changed, the loop water is protected for below freezing, then there are only a few probable causes left.

    The 5 ton unit High Pressure Lockout actually has 3 Pressure switches (Carrier schematic but protection all manufactures would want) one sensing Freon high pressure, one for inlet water pressure and one switch sensing outlet water pressure. Assuming the water side pressure switches are not seeing blockage in the water side heat exchanger due to icing (Freon is adequate & flow is adequate as assumed above) then the Freon side HP pressure switch is seeing a high Freon pressure.

    Your unit tripped on this protective feature, so what would cause a high Freon pressure? In the heating mode the air return coil is the condenser.

    Low air flow due to 1) closed air return dampers, 2) air restrictions in return air filter(s) or return path, 3) ECM motor dip switches incorrectly set up causing reduced air flow 4) ECM motor degraded over 4 years of continuous run 5) Accumulated dust in the return air coil due to "Horse Hair" filter use rather than the 3M style high efficiency dust removal filters. 6) ECM motor set up to run as single speed fan on the thermostat.

    For future reference and when a Tech arrives: 10 Steps Servicing Geothermal Heat Pump
    http://contractingbusiness.com/service/10-steps-servicing-geothermal-heat-pump
     
  18. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    A
    Again, you are not helping here by being speculative in every direction.

    1) A lack of flow might have a slight effect on HP capacity but not a does not create the symptoms, thus if EWT and LWT are within the range which was reported here, it does not explain the symptoms, namely the ongoing running.
    2) The units would go into lockdown, not lacking capacity if the water flow would be off too much. By no means you can loose enough capacity to cause the symptoms by air in the loop, or lack of flow. The temps on the water side are OK so far, so before we make any further assumptions we need to know the flow.
    3) When a unit runs it takes a certain amounts of BTUs out of the refrigerant circuit, and produces a certain amount of BTUs, and those BTUs have to go somewhere. Unless the refrigerant circuit is not producing the BTUs. That is why you need the heat extraction, that is why you check this first.
    4) We have no evidence of Lockouts, air in the loop, low air flow, or not enough water flow. None of those issues would cause the symptoms described. So please stop talking about it.
    5) A loop never freezes. Slush never forms in the loop. It is always the heat exchanger in the heat pump which is the coldest spot in the system where where slush formation or freezing occurs...
    6) Loops are not made of PVC anymore but HDPE

    I know you mean well, but you are going in too many directions without facts guiding you.

    To Maurice: A few concerning things:

    1) The pond is 300ft away, so you have at least 600ft of line, and an 32 elbows, sounds like a pressure drop nightmare to me for the 21 gpm you need to keep the heat pumps happy. What is the size of the line running out there to the pond?

    A very concerning thing:
    No system deserves or needs 26-116 pumps. 116 pumps make about 10% more ft/hd as 26-99, but use 400 watts each, instead of 230 watts. They are very inefficient.
    1) Whenever I see 116 pumps I know the installer is un-evolved.
    2) Whenever I see (2) 116 on a large HP I know he does not understand energy efficiency of the system, since now someone is paying for 800 watts of pumping.
    3) When I see (2) 116s on a small 2 ton HP (which I have never seen) there is either a complete lack of knowledge about running theses systems efficiently, or someone is trying to bandaid a system which is not designed for good flow and low pressure drop. The numbers we have see so far (6 gpm of flow on the 2 ton despite (2) 116 pumps) suggest a lack of knowledge.
    4) Obviously when both units running, you are (were) not getting enough flow despite your enormous pumping effort.

    Sorry for wing so harsh here, but there is more than one issue with the system, beyond the 24/7 running. It will come down to your contract, and the willingness of the installer to understand when is not going as it should be.
     
  19. mrrxtech

    mrrxtech Member

    2) & 4) The 5 ton unit went into lockout on High Pressure more than once. The given cause is Low Air Flow plus a list of return air issues which hints at low air flow. Included in this lockout are water side pressure switches. There is no way to know which of the 3 switches caused the lock out from data given by Maurice, so I have considered all 3 causes.
    5) Freezing in the HX would cause a HP Lockout due to the water side Pressure switches.
    6) My loops are HDPE, I was thinking Polyethelene but writing PVC as the acronym instead of PE. My mistake.
    7) I have been asked to not talk about two issues by another Tech, but I believe there are two issues, and from what I read, you also feel there are two issues.

    Asking questions and making assumptions then proving them correct or false is what we are doing. Rehashing information might cause someone to catch a fact that was missed due to an error in communication. Like the unit running 24/7 and doing nothing for the house, while others say that's impossible and is not the case here. There is some confusion here.
     
    Last edited: Mar 7, 2016
  20. mrrxtech

    mrrxtech Member


    2 ton:
    according to the manual the 2 ton locks out over high pressure, no reason in heating mode, the filter is clean. they changed the board the first time. they reset it after the last lock out, now waiting to see if it will do it a third time

    My mistake on which unit locked out on HP, it was the 2 ton unit.
     

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