Indiana Problems with cooling

Discussion in 'Maintenance and Troubleshooting' started by dewed, Aug 27, 2018.

  1. dewed

    dewed New Member

    This is my first post. I have read many other posts but now, I guess, it's my turn to ask.

    I have a ClimateMaster Tranquility 27. It's been installed for about 6 years and until about a year and a half ago it ran flawlessly. Loved it...until the past year and a half.

    2 winters ago I started having trouble with the unit heating. I live in Indiana and it was brutally cold to start off. I suspect after my HVAC guy came out, it was an issue where it literally froze the ground around the closed ground loop that I have. As I recall, the EWT was 28 or 29 and the LWT was 25. He told me that was likely the cause. I opted out of elec Aux heat on my intial install so I fired up the backup propane boiler I have and got thru the winter. No biggie. Made sense.

    Then last summer, I started having cooling issues, System would simply not keep the house cold. Seemed odd. My HVAC guy came out and checked everything - I mean everything. Couldn't find the problem. All things looked fine. Refrigerant was good, loop was running within good temps, etc etc. I had found on posts about the themistor possibly being bad after doing some research, so he swapped that out and the capacitor too. I honestly forget if after that it happened again but I'm sure it did.

    So here we are this summer. About 2 or 3 weeks ago the system had trouble keeping the house at the temp set at 69. I check the compressor operation and it's not running. No fault codes, no obvious reason it shouldn't be running. I check the EWT and LWT and they haven't ever taken a reading above 83 and 90 respectively. I do run a desuperheater as well. I have the DSH therm on the unit set to 150.

    My solution has been to power cycle the system and cross my fingers that it comes back on. About one in 3 times the system seems to return to normal for a while. No rhyme or reason to how long it will run until once again, it starts getting warm and I notice the compressor is no longer running.

    I'm at a total loss as to what the heck is going on. I have looked at the troubleshooting chart for this condition: Fans runs, no compressor running. It states:

    Check these:
    Thermostat position
    Insure thermostat set for heating or cooling operation

    Check. not this

    Unit locked out
    Check for lockout codes. Reset power.

    No lock out codes.

    Compressor Overload
    Check compressor overload. Replace if necessary.

    I'm not sure what this means or how to check Compressor overload.

    Thermostat wiring
    Check thermostat wiring at heat pump. Jumper Y and R for compressor operation in test mode.

    I not sure what the purpose of this is but I'll try it. I'm guessing this means to jumper it and see if the compressor actually works. the compressor works great when it actually comes on.

    Also in the troubleshooting guide for "performance" problems it states to check the Reversing valve. Not sure where or what this is but I'm guessing it's what reverses the refrigerant flow to turn in into AC rather than a heat pump. need Help on this, but again, when the system runs with the compressor it works great.

    So, what to check? Other than it being a faulty board, I can only guess possibly a bad thermostat but I have no idea. Any help figuring this out appreciated. I live in the boonies and my qualified HVAC guy is expensive and has already taken a few stabs at this so I want to figure this out or narrow it down before I call him back for the this.

  2. arkie6

    arkie6 Member Forum Leader

    Several years ago Emerson had an issue with the rust inhibitor they were using in Copeland scroll compressors, like the one in your unit, causing the Thermostatic Expansion Valve (TXV) to stick. I'm not sure if your symptoms align with this issue, but it might be worth investigating as a possibility. You can search google for [copeland stuck txv] and get hundreds of hits on the subject including service bulletins and the fix.

    Here is one example from Carrier:

    "Ongoing testing and reports from the field indicate that Thermostatic Expansion Valves (TXV) in 1.5, 2 and 2.5 ton indoor coils installed with the above listed condensing units may not
    maintain the correct SuperHeat (SH) in certain situations. The end result is a lack of cooling for the homeowner due to high SH and low suction pressures measured at the outdoor unit."

    Here are some TXV symptoms from the Climatemaster troubleshooting guide here:

    TXV Stuck Closed (or Restriction)
    • High superheat
    • High subcooling
    • Low suction
    • High discharge pressure
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Low refrigerant would be my initial guess. Have your heat rejection into the loop field checked. Then you know if your refrigerant circuit is performing up to specs.

    What size unit do you have? Model Number?

    If you have a 7F difference between EWT and LWT, your compressor must be running, otherwise you would not reject heat into the loop field.

    Freezing the ground is not a big issue, it is quite normal if you are sending out 25F water fluid.
  4. dewed

    dewed New Member

    My HVAC guy, vacuumed and weighed the refrigerant last summer and it was not low - he thought the same thing - no dice. If the refrigerant was low, then the system wouldn't perform well whatsoever. The system works great - when the compressor runs. The air coming out is really cold.
    I don't think it's the loop anymore. Initally, I thought maybe it was. The weird thing was, during last winter when we had a warm day and it rained, the system couldn't heat as well, which was weird, because you'd think the ground would warm up, ground moisture increase and we'd have better heating. Not the case whatsoever, it seemed to make the problem worse.

    It's a 5 ton CM system, model TTV049AGC01ARKS.

    I agree that the compressor seems to run fine - when it runs. The issue is it seems to just randomly not run, when it does run, the system cools and heats just lovely but then for no apparent reason the compressor just stops running. Like last night. It was warmer inside the house than outside. Frustrating.
  5. dewed

    dewed New Member

    I went down this morning and randomly my compressor is running again and the air that is coming out is lovely. I didn't touch or change anything. The system didn't run all night then magically, it's running this morning. the EWT is 84.4 and LWT is 90.1. Totally random operation. So I guess, at this point, I'm down to TXV valve faulty and checking the heat rejection into the loop field. I'm no expert, but if the heat rejection into the field was an issue, would it also affect the heating in the Winter as well? I did call Indy Geothermal (The loop installer) about this a few months back and he told me he really didn't think it was the loop when I described the symptoms. I told him I thought maybe the loop was undersized and he said, "No, I seriously doubt it". It's a 500' horizontal loop with 20% methanol.
  6. dewed

    dewed New Member

    One more piece of information. Last night, since it was warm in the house and I couldn't sleep anyways. I decided to test the thermostat. So i dug up a piece of wire and tested jumpering the Yellow (Y) to Red (R) at the control board in the unit. When I jumpered it, I could definately hear a "click" at what I'm guessing is the relay to the compressor. I expected the compressor to immediately come on, it did not. I really don't know if doing that jumpering should immediately engage the compressor or if there is some sort of safety that prevents the compressor from immediately coming on and off to prevent damage. Before I did all this, I jumpered and put the system into test mode so that it would speed up the cycling 20 times like the troubleshooting manual says. It wasn't until after i did this test that I read you can damage the compressor if you cycle it too quickly. I don't think that's the case here because the compressor never engaged when I did the Y/R jumpering. Something just clicked when I did the jumpering, it was like an on/off switch every time I jumpered. I held the jumpering for maybe a minute and the compresssor never engaged. I'm not sure what behavior I should get with compressor engagement when I do this so I'm not sure if what I did eliminates the house thermostat or not.

    When I removed the face plate from the thermostat, I did notice that the batteries on the therm had begun to leak - not super bad, so I was thinking now that maybe I had a bad thermostat. I put in new batteries but I really think my thermostat draws power from the CM system and the batteries are not needed. Thermostat powered on without batteries but I put new ones in anyways - just to see if that could possibly having any sort of effect on operation - it didn't seem to make any difference and I suspect the thermostat is fine.

    FWIW, the thermostat model is a TRANE TCONT802AS32DAA
  7. dewed

    dewed New Member

    Update: I called ClimateMaster tech support this morning. My serial number P14590211 does not have the TXV valve with the rust inhibitor in it. They told me it happened with units starting with serial number "R". Of course, that doesn't eliminate that it could be a bad TXV valve.

    I may not have mentioned this, but the termistor was replaced last summer at my behest since when the problem first occured in heating mode I did get an error that indicated it "could be" a bad thermistor. I looked back at my notes and this was the error.

    Operating Conditions that can cause Low Air Coil Temperature Fault (code 5)

    For whatever reason, CM, doesn't allow me to cut and paste the text from their PDF without a password. It does states that it could be the thermistor OR less commonly a bad expansion valve or low refrigerant charge. We know the thermistor was replaced and my HVAC guy checked refrigerant so I'm leaning towards the TXV valve being the prime suspect here.

    I'm almost at the point of just having him replace the TXV valve and see if that fixes it. It's costly to have him and come go each time so I'm just wondering if doing the TXV valve is money well spent. Thoughts?

    CM tech support said something about putting a logging device on the system to see if we can catch it in the act. What does that involve? I'm not sure my HVAC guy has the equipment to do that.
  8. geoxne

    geoxne Active Member Forum Leader

    Do not change your TXV. If you had a a bad TXV you would get a lockout code. The next time it stops do not reset , take a look inside at the green status light. If it is solid green all safeties are normal. If it is slow flashing it is in fault retry mode. If it is fast flashing it is locked out.

    If it has locked out you can short the test pins and count the flashes and lookup the code. The code will be lost if you power off the unit.

    If you are NOT getting lockouts. It is an electrical or control problem.
  9. dewed

    dewed New Member

    Roger that. we’ll start with the thermostat since it did have leaky batteries and therfore is prime suspect. it’s true that i havent gotten any lockout codes recently and i’ve been watching for them religiously, crossing my fingers i’d get *something*. been solid green everytime
  10. arkie6

    arkie6 Member Forum Leader

    Have you checked your compressor main contactor (a big 2 contact relay)? You could have degraded/worn contacts such that the contactor pulls in when demanded, but 240VAC doesn't pass through the contacts to the compressor motor. This could give you the "click", but no compressor start. Also, most compressors have a time delay relay in the contactor control circuit that prevents restart of the compressor for ~3 minutes give or take following a compressor shutdown.
  11. dewed

    dewed New Member

    I'll have him check that when he comes out (hopefully today).
  12. dewed

    dewed New Member

    My guy found the problem. I was skeptical we could get the system to act up while he was here - but he did.
    Wasn't the thermostat but I did have him put in a fancy Honeywell 9000.
    He put in some AC Renew just to be proactive.

    The issue is the control board. Stat was asking for cooling and then all of a sudden the compressor turned off and he checked the voltage from the board out to the relay and it was reading 14.9V and it should have been 24V. No rhyme or reason as to why. No error code/no nothing. I'm relieved we found something and I appreciate all the insight.

    He has a new board on order and if for some crazy reason that doesn't resolve it, I will post further.
  13. dewed

    dewed New Member

    Just a quick update. We replaced the control board and he ran all the tests and it seemed to work fine. Then, the same night he replaced it, the AC stopped working, no error codes, no nothing. He is having me remove the Y2 cable to see if the 24V solenoid on the compressor may be shorting out during the second stage call down the low voltage line. He said he has seen this once before on a Trane with a Copeland compressor. He is calling in our geo experts that did the loop to see if they have any input. I have told him that at this point I would like Climate Master to replace the entire unit since this problem has gone on for more than a year and a half. We've replaced part after part, checked a ton of things and still not resolved. The problem is so intermittent it's hard to catch it in the act and there is literally no error code. Thoughts?
  14. dewed

    dewed New Member

    removing the Y2 control wire doesn't seem to have resolved the issue. Back to square 1. Suggestions at this point?

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