Pennsylvania Condensation issue, flying blind - any guesses?

Discussion in 'Maintenance and Troubleshooting' started by ourhouse890, Jan 26, 2021.

  1. ourhouse890

    ourhouse890 New Member

    I've got a 5-yr old 5-ton ClimateMaster TEV064BGD02CLTS and am experiencing intermittent condensation issues coming from within the unit. Right now I would estimate there's 1-2 gallons of condensate sitting in and around the unit and running across the floor. It's been like that for a few days now but this has been happening intermittently for years.

    Unfortunately I'm flying a little blind because I geeked out on the air side and have a Trane XL950 thermostat to control 6 zones and it can't see wet side data like most other ClimateMaster owners can do via their thermostat. I did have an ACDU01 communicating tool the first couple years but somehow it got fried and won't turn on anymore. Anyway..

    Info/clues:
    Eastern Pennsylvania
    House is 5 yrs old, this is the original unit
    ~2200 sq ft first floor
    ~1800 sq ft second floor
    ~2100 sq ft basement
    System is installed in the basement which is kept at 68-70F and 43-47% humidity year round
    4 vertical loops run in parallel, 225 ft deep each
    Loops are 3/4"
    Piping between unit and where loops split is 1.25"
    Everything is well insulated

    Now that I'm home full time in covid world, I've been able to observe a little closer what's going on.

    The last couple nights have been among the coldest of the season so far. The unit was finally running in second stage for a good chunk of the night two nights ago and I would assume it's not a coincidence that's when I woke up to a big slug of condensate for the first time this year.

    So my question - does it seem like my loop is undersized and the entering water temperature is too low? Something seems wrong if the factory insulation inside the unit isn't thick enough to prevent this much condensation in a conditioned environment. I can actually watch the condensation seep through the insulation and drip down.

    I just ordered an ACDU03 communicating tool and will be able to report wet side data in another week or so. In the meantime, any help or educated guesses are appreciated!
     
  2. gsmith22

    gsmith22 Active Member Forum Leader

    condensation occurs when relatively warm+humid air touches a relatively cool surface. If the units are in your basement, and the basement air is 68-70deg and 45% humidity, using a psychrometric chart, the dew point of that air is about 57 degrees. So if anything in the unit is colder than 57 degrees, and the air can contact it, its going to condense. I would look at your coaxial heat exchanger because in heating mode, the refrigerant needs to be colder than the incoming water in order to get heat out of the water and into the refrigerant. Units have condensation pans/drains to collect and get rid of the condensate. Possibly that system is blocked or your condensate pump is no longer working? I don't think you have a geothermal heating issue, I think you have a blocked condensate system (or non funcationing condensate pump)
     
  3. ourhouse890

    ourhouse890 New Member

    Thanks for your response.

    I'm aware of the large condensate pan for the air coil. It's about two feet off the ground on the left side of the unit and is where the external condensate connection is. It gets good and wet in the summer and bone dry in the winter.

    My external condensate pump is working fine, it's collecting excess water from the humidifier this time of year and discharging it normally.

    But I'm having a hard time tracing the piping to find the coax heat exchanger. Is it in the very bottom of the unit all the way in the back totally wrapped in black foam insulation? If so, yeah that's where all the condensate appears to be coming from. The bottom of the unit is all rusty back there. There's even some ice on the outside of the black foam insulation in one or two spots. But I don't get where that condensate is supposed to go. It's all the way at the bottom of the unit, ~2 feet below the air coil condensate connection and at the same elevation as my external condensate pump. Is there a second condensate connection somewhere in the bottom of the unit that's supposed to be piped out? (was the installer supposed to elevate the whole system to put it above the condensate pump?)
     
  4. gsmith22

    gsmith22 Active Member Forum Leader

    follow the incoming/outgoing ground loop water lines from where they enter the cabinet they should go to a round coil-like thing which is the coaxial heat exchanger with a portion of the refrigeration loop. I attached a page from one of the waterfurance 7 series manuals that shows it insulated in green but I imagine it could be any color. In heating mode in the middle of winter, that loop contains incoming/outgoing water in the 30-40 temp range (or whatever your ground loop temp currently is) and the refrigerant (in liquid state) even colder than that (heat has to move from the ground water to the refrigerant). So basement air is contacting that coaxial heat exchanger and condensing. Your air coil is where all the heat is (both in the refrigerant and air moving across it) so it isn't going to condense in the winter (summer yes as you noted when refrigerant flows are opposite). What I don' t know or understand is if that coaxial loop is supposed to condense (ie waterfurance cannot insulate it enough to stop it) and so they collect condensation off of it as part of the condensate system or it isn't supposed to condense and therefore there isn't a system and somehow you have lost the insulation preventing the condensation. If there is a condensate collection system for the coaxial heat exchanger (just like there is at the air coil as you note), then that system is probably blocked and needs to get unblocked. If there isn't a system, then there has got to be insulation missing somehow allowing the condensation. probably easier to see all of this by taking a panel off the side or back rather than the front.

    Just to be clear, I'm kind of spit balling here because I have not investigated any of this myself but just trying to follow the science ie where could condensation possibly be coming from in heating mode
     

    Attached Files:

  5. ourhouse890

    ourhouse890 New Member

    Great diagram, was looking for something similar for my model but haven't been able to find it. Anyway, my system is laid out very similarly, the water in and out connections are in the lower right just like the image. They run straight back and at the back of the unit make a left turn into the coaxial HX. It's factory insulated, hasn't been messed with and is sitting in a rusty puddle of condensate.

    Does it make sense I'm getting a little bit of icing? On the coaxial HX in the image you provided there's a water connection all the way at the bottom. Right above it is a capped refrigerant pipe. That cap is well insulated on mine but there's some ice on the outside of the insulation and a dollar bill sized puddle of ice cold condensate under it. That's not the main source of my condensate issue though, the bulk of it appears to be coming off the coaxial HX as a whole. Just wondering if that icing is a sign something is wrong and I'm getting way colder in the coaxial HX than the insulation was designed for.

    There's no mention in the IOM for my unit of an internal condensate pump or an external condensate connection for anything below the air coil condensate drain. It talks about installing a secondary containment pad for horizontal systems but that seems to be a CYA statement since those typically go in an attic and you can't afford a single drop of condensate leaking down. For vertical units like mine it just says to put it on a shock resistant housekeeping pad which mine is on.
     
    Last edited: Jan 27, 2021
  6. gsmith22

    gsmith22 Active Member Forum Leader

    sorry, I thought you had a waterfurance unit (getting confused between threads) and that is why I posted a waterfurnace diagram. All heat pumps will look/function similarly however so it should generally be the same and looks like you found the coaxial coil. If its factory insulated and hasn't been messed with, then it doesn't make sense this is normal (or at least doesn't make sense to me that they would construct a unit that leaks all over your floor).

    I am by no means an HVAC technician, however, I will relate the following because it stuck in my head: prior to getting our geothermal, one of our 30 year old air conditioning units was building up ice on the outside of one of the copper line set pipes coming out of the outdoor compressor/condensor coil. the unit wasn't functioning well either so I had an a/c tech take a look and it was low on refrigerant. We were already in the process of moving to geothermal (I think well drilling was about to start) so the HVAC company doing the geothermal topped off the refrigerant just to keep it going for a few months (the leak was extremely slow). Prior to calling the a/c tech, the refrigerant line entering the outdoor coil coming from the inside air coil was building up a tremendous amount of ice on it and as soon as the refrigerant was topped up that all stopped. Apparently, low refrigerant causes extremely low temperature refrigerant at the low pressure/low temperature line just prior to entering the compressor and since this line was outside in the summer, there was plenty of warm+humid air to condense and form ice on it.

    On a water to air geothermal heat pump in heating mode, your coaxial heat exchanger will have low pressure/low temperature vapor in it at the refrigerant line coming out of the end of the coaxial heat exchanger just before it enters the compressor as it is the equivalent piece to where ice was building up on the lineset of my low refrigerant air conditioner. I have no idea how long my unit was low on refrigerant because I had purchased the house just prior to noticing this (on a side note, the old owner left lots of nice surprises like that) but I suspect it might have worked okay for a while and then just eventually got too low and couldn't function. Its possible you have a refrigerant leak or the unit wasn't full from the factory but I think you probably need to have a tech take a look and check the refrigerant levels. ice on the outside of the insulation around the coaxial heat exchanger isn't normal. and when that ice melts is when you get water all over your floor. As soon as my air conditioner was topped up with refrigerant, there was no more ice on the outside lineset.
     
  7. ourhouse890

    ourhouse890 New Member

    Thanks again for all your time and responses. I happen to have the installing contractor coming out in a couple weeks to address a zoning issue, will see if they can check the refrigerant while they're out.
     
  8. gsmith22

    gsmith22 Active Member Forum Leader

    what little reading I had done on it at the time indicated it was a really bad thing for the unit to have the ice build up and most things online suggested to turn the unit off. I didn't get into why that was the case but I turned it off (and the ice melted). If it was me, I would probably have someone take a look as soon as possible. I wouldn't call this "maintenance"; something isn't correct.
     
  9. ourhouse890

    ourhouse890 New Member

    Just peeling back the layers of the onion a little more... There's a similar and possibly related issue in the summers. I've noticed a good portion of the copper tubing up at the air coil frosts over. When the unit turns off it melts and a lot of it drips in the condensate pan like it's supposed to but there's also a good amount that misses the pan (some components that get frosted up aren't directly above the tray). It drips down thru the unit and eventually finds its way on the floor too.

    It's been like this for as long as I can remember. I've casually mentioned it to techs who were here for other repairs and they've thought something didn't seem right but don't remember if anyone actually checked the refrigerant or not.

    Would be awesome to finally get it fixed so I can clean out the rust and mold in and around the unit. I'll be sure to let you know what they find.
     
  10. gsmith22

    gsmith22 Active Member Forum Leader

    in cooling your air coil is the location of the low pressure/low temperature vapor in the refrigerant line just like your coaxial is during heating. they are both heat exchangers that trade positions in the system via the reversing valve. So it makes perfect sense that if you are getting ice/condensation during heating at the coaxial, you would get ice/condensation during cooling at the air coil. The air coil issue is harder to identify though because you get condensation there normally during cooling because warm air is being forced over the cold tubes condensing water. During heating, you are forcing cooler air over the warm air coil so no condensation can occur. Ice should never be forming though. My guess is your system has low refrigerant probably from the factory
     
  11. ourhouse890

    ourhouse890 New Member

    Update: I received the ACDU03 diagnostic tool and was able to pull a 'reduced performance cool 1' fault.

    The service tech was out today. Refrigerant is fully charged, he wasn't able to identify any obvious performance issues in heating mode but in cooling mode he found the TXV was 'not reacting properly.' A replacement valve has been ordered and will be swapped out in a couple weeks.

    Hopefully it's that simple. I don't like that he wasn't able to find any issues in heating mode but he at least saw the condensate all over the floor and agreed it wasn't normal. My fear is some sort of debris in the system that will be hard to chase down and eliminate. We shall see...
     
  12. gsmith22

    gsmith22 Active Member Forum Leader

    the TXV could very well be your problem. it regulates how much of the low pressure/low temperature vapor refrigerant is allowed into the coaxial heat exchanger which is where your condensation issue is coming from. A txv valve restricted or not opening enough produces symptoms like a refrigerant under charge. hopefully changing out the txv fixes your issue
     
    Last edited: Feb 5, 2021
  13. SShaw

    SShaw Active Member Forum Leader

    Does the diagnostic tool tell you the entering and leaving water temps?

    It's hard to understand how you're getting gallons of condensate, unless you are pushing tons of air through the cabinet from which to extract the water. The HX coil should be isolated from the fan and air stream.

    Are there holes inside the unit allow air to flow past the HX?

    Is it possible there's a water leak, maybe from a humidifier?

    Keeping the basement at 43-47% humidity could be contributing to the problem. Humidifier manufacturers recommend a substantially lower value in winter to guard against damaging condensation inside the home (on windows, inside walls, etc.) See attached table from AprilAire for recommended levels vs outside temperature.

    You could try lowering the humidity level to 35% or 40% and see how that impacts the condensation inside the unit.
     

    Attached Files:

  14. gsmith22

    gsmith22 Active Member Forum Leader

    its not condensate in the traditional sense as would be expected in cooling mode at the air coil (evaporator during cooling). Typically with too little low pressure/low temp refrigerant in the evaporator (the coaxial coil during heating mode) it causes ice to form around it. the ice is condensate (from ambient air hitting the very cold evaporator) that freezes at the surface. typically that ice then also melts as system turns off/on and that is where all the water is coming from at the coaxial. The debate at this point (or maybe just in my head :)) seems to be why too little refrigerant is in the evaporator. Typically its from low refrigerant charge but his tech says that is fine and spotted an apparent issue with the TXV which can masquerade as low refrigerant so I suspect they are on the right track.

    Even if he lowered the interior air humidity to say 35%, the dew point for 65 deg air is right around 50 degrees so any surface colder than 50 degrees is going to cause condensation to form. With the coaxial coil insulated, it has to be crazy cold internally for its insulated outer surface to be forming ice in any reasonable interior winter time temp/humidity combo.
     
  15. SShaw

    SShaw Active Member Forum Leader

    In the process you describe, the water is coming from the air. What doesn't make sense to me is the cabinet is a closed box with a small quantity of air inside. Unless there is a constant quantity of new moist air being pumped in, one can only draw so much water from the air inside that cabinet.
     
  16. gsmith22

    gsmith22 Active Member Forum Leader

    I would hardly consider the cabinet sealed and when the unit is running, there is a big fan moving air through the coil above it so I suspect there is plenty of air. plus pulling moisture out of the air will almost certainly create air movement currents within the cabinet if the fan wasn't running due to temperature/pressure differences. Careful with the "moist air" concept too. its all relative; you don't need New Orleans in your basement to create condensation. if you use a psychometric chart, you can create condensation in a typical basement environment (65 degrees 40% humidity) with a surface at like 55 degrees. I was actually surprised myself at that temperature being so high when I looked it up. I don't have condensation all over my coaxial coils in my basement so what that tells me is the temp of his coaxial is too cold. that is typically a low refrigerant charge or in this case an issue with the txv
     

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