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  1. #1
    Join Date
    Dec 2007
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    6

    Trane XL16i / Honeywell VisionPro IAQ Question

    Hello,
    First I'd like to say that this is a great and enormously informative forum and I want to thank in advance everyone for their help.

    I have a Trane heat pump system XL 16i, outdoor model# 4TWZX6036B1000AA indoor model# 4TEE3F37B1000AA (I believe this pertains to the air handler) controlled with Honeywell VisionPro IAQ (YTH94Z1C1002) thermostat. The backup is electric strips.
    The system was installed in May and had worked great until the temperatures dropped recently. What happened was the system would switch to Aux Heat when the temperatures dropped to about 41F. Needless to say, when running Aux Heat, my electric usage was not acceptable (I try to monitor my meter daily, sometimes more often) it went from about 45 KW/day (while running the heat pump) to about 110 KW/day (on Aux Heat).
    When I had the unit installed (in May) I was told that there's a "cut off" temperature below which the heat pump will not be able to operate (hence the need for Aux Heat) and that it was about 45F. I recall the technician configuring the thermostat and setting that temp to 45F. I asked him then if he could lower it but he refused saying that this was the best setting and if I didn't want to run Aux Heat and continue to run Heat Pump even below 45F all I had to do is set the thermostat to Heat (as opposed to Auto). I thought that it would work for me but obviously I couldn't really test it until the fall when the temperatures dropped below 45F. Well - it didn't work, i.e. even if I set the system to Heat and it was below 41F the system would switch to Aux Heat. So I gave up and just lowered the temp to prevent the system from running as much (and it being as costly when running Aux Heat).
    Then on a few occasions, while walking in my neighborhood I noticed that my neighbor's heat pump was running even though the temps were around 30F (his unit is Bryant, older and less efficient model than mine). That prompted my search online to find out if there's anything that can be done with the settings on my system that would allow for the heat pump to run at lower temps than 42F. That's how I found this great site! From here I found the installer's manual to my thermostat and was able to learn about compressor lockout and Aux Heat lockout settings. I also learned about other people (much like my neighbor) running their heat pumps in temps much lower than mine was set to.

    So finally yesterday I went through setup settings and modified some of them. Listed below are the items I modified and/or have questions about:

    0176 - Heat Or Heat Pump Aux stages. I believe the value set by installer was 1, I set it to 2.

    0350 - Heat pump compressor lockout. The value set by installer was 45F (or 40F), I changed it to 15F

    0360 - Heat pump auxiliary lockout. The value set by installer was 40F (or 45F), I changed it to 25F

    0401 - Number of bedrooms. The value set by installer was (default) 2, I changed it to 5 (I have 3 actual bedrooms but also an office and a media room)

    0402 - Size of house. The value set by installer was (default) 10 (1000 sq. feet), I changed it to 19 (1900 sq. feet)

    After making the changes I let the system run for about a day and here's what I found:

    The good:
    My total daily energy consumption decreased to about 60KW from over 100KW when using Aux Heat (the weather/temps outside on both days were pretty much the same). And all that while actually INCREASING the indoor temperature - now I have the thermostat set between 68F (night) and 70F (day), and previously while running on Aux Heat I had it set at 63F (night) and 66F (day). So the house is much warmer and I'm using about a half of the energy.

    The bad:
    The system (heat pump) seems to be running a lot - I would say about 75-80% of the time with short breaks every now and then.

    Questions:

    1. Is there a problem with any of the settings (listed above) that I modified?
    2. Related to option 0176 - how do I know how many stages my unit has?
    3. Is it a problem for the heat pump to run almost continuously? Will it wear out / break sooner / cause any other problems?

    Any help would be greatly appreciated.

    BTW - I live in the foothills outside of Seattle, WA and my daily winter temps. are normally between 25F and 45F.

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
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    5,060
    It sounds as if you have figured it out. Your dealer must have stock in the power company. Your heat pump during cold weather should be running a lot longer and if properly charged should not be a problem. Depending on what heater package you have and how it is wired to the Tstat will determine the AUX heat stages. Look on the front of your airhandler and see if it was marked. You are looking for BAYHTR-------- or it may be on your contract.

    I would call the owner of the company and have him send a competent tech out to check it for you.

    I would also have them check to make sure that your unit is wired correctly.

    Do you know if you have variable speed Comfort R set up?

  3. #3
    Join Date
    Dec 2007
    Posts
    6
    Thank you for your reply!

    It certainly sounds like there's a connection between the installer company and Puget Sound Energy (local power company)
    In reality though - based on a few threads I read on this forum I guess the technician entered the settings based strictly on the thermal balance point not the economical one (I wonder where he got the numbers he entered from, manufacturer's manual? the company's guidelines...?).

    The front of the air handler has a plate/label with what looks like a list of all different models of equipment but none of them is marked in any way (as being the one installed). I looked in my paperwork and the only place I found any description for backup heat strips is in the initial bid I received from the installer. It is BAYHTR1415BRKA, and the description is "matched backup - supplemental heat strips 15KW."

    I'm not exactly sure I understand what "variable speed Comfort R" is... if you're asking about the air handler then yes, it's variable speed; if you meant something else could you please clarify (and describe how to check what I have and how it's set up)?
    Thanks again!

  4. #4
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
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    Comfort R will give you a ramp profile from the blower in both the heating and cooling mode. The fan will start out at at 50% airflow for the first minute then ramp up to 80% and after 8 minutes it ramps to 100%.

    Make sure that you have first and second stage wired correctly.

    Unless he did a manual J load calculation on your house he would have absolutely no way of knowing the thermal value of your house.

  5. #5
    Join Date
    Dec 2007
    Posts
    6
    From your description, the sounds of the system, and a slight recollection of the conversations with sales rep it appears that I do have Comfort R.
    I suppose there wouldn't be a way to check if the first and second stage is wired correctly without actually calling a tech, would it? (BTW - so I'm guessing from your question that I have 2-stage strips, correct?)

    I'm almost positive that they didn't do any manual J load calculation.

    I just called Trane (well, their tech rep) and explained the situation in general terms and she didn't see any issues with lowering the lockout temps. When I asked why an installer would set them so high, her guess was: "that's what they were comfortable with." I wouldn't call it a very scientific approach and frankly after hearing that I don't have too much trust in the installer company any more so I'm hesitant to call them for anything.

    In light of what Trane's tech rep told me what doesn't make sense is the installing tech's absolute refusal to adjust the settings even after I specifically asked him to do so (my guess would be that those were some "factory settings" and he was configuring the system "by the book" while now I know that it's clearly not the case).

    Also, another thing that doesn't make sense is that before installation I got bids from three different installers (on two different systems - one on Carrier and two on Trane which I ultimately chose) and all of them were saying more or less the same, i.e. the heat pump works when outside temp is above around 43F (+/- 3F); when below that, supplemental heat strips take over. Now I found out that it's not the case, or at least it doesn't have to be (contrary to what I had been told). I wonder how many other heat pump owners curse their new heat pump system when their utility bill isn't any lower than it used to be prior to getting their new system (due to simple misconfiguration)...

  6. #6
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by Nordic View Post
    what doesn't make sense is the installing tech's absolute refusal to adjust the settings even after I specifically asked him to do so,I got bids from three different installers and all of them were saying the heat pump works when outside temp is above around 43F (+/- 3F); when below that, supplemental heat strips take over. I wonder how many other heat pump owners curse their new heat pump system when their utility bill isn't any lower than it used to be prior to getting their new system (due to simple misconfiguration)...

    he should have adjusted it to what you prefered

    in the winter my heat pump is never locked out, but my electric heaters are locked out until 15 degrees

    your comfort level may vary

    heat pumps do have a bad rap due to miswiring and misconfiguration

    this is why you must choose your contractor carefully!



    .

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,586
    I wouldn't lock out the compressor till -10.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
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    14,915
    0350 - Heat pump compressor lockout. The value set by installer was 45F (or 40F), I changed it to 15F
    Their 45º setting is pretty rediculous, I would just turn that function off, or set it to -10º, or even lower.

    I have a suspicion that there was a miscommunication to, or misunderstanding by, the tech, and he was actually supposed to be setting the aux heat lockout to 45º, not the compressor lockout.

    0360 - Heat pump auxiliary lockout. The value set by installer was 40F (or 45F), I changed it to 25F
    Careful with that one, you may end up having to increase it. It locks the aux heat out completely if it is above 25º outside. It depends on a lot of factors, but the heat pump alone is often not able to maintain the temperature in the house at higher temperatures than that.
    If you start noticing the heat pump is not able to maintain the set temperature, try bumping this setting up to just above the outdoor temperature the heat pump is not able to maintain the indoor temp.

    0401 - Number of bedrooms. The value set by installer was (default) 2, I changed it to 5 (I have 3 actual bedrooms but also an office and a media room)

    0402 - Size of house. The value set by installer was (default) 10 (1000 sq. feet), I changed it to 19 (1900 sq. feet)
    These settings are only for fresh air intake, if you do not have a fresh air intake duct, with a damper controlled by the thermostat, you can turn this stuff off, or leave it alone.
    If more government is the answer, then it's a really stupid question.

  9. #9
    Join Date
    Dec 2007
    Posts
    6
    Thanks again for everyone's comments and suggestions.

    Quote Originally Posted by mark beiser View Post
    Their 45º setting is pretty rediculous, I would just turn that function off, or set it to -10º, or even lower.
    I don't think this will really matter - the temps here hardly ever drop below 20F but I suppose I could lower it anyway just in case...

    Quote Originally Posted by mark beiser View Post
    Careful with that one, you may end up having to increase it. It locks the aux heat out completely if it is above 25º outside. It depends on a lot of factors, but the heat pump alone is often not able to maintain the temperature in the house at higher temperatures than that.
    If you start noticing the heat pump is not able to maintain the set temperature, try bumping this setting up to just above the outdoor temperature the heat pump is not able to maintain the indoor temp.
    That was more or less my goal, i.e. to not have to use aux heat at all. So far the heat pump by itself seems to be doing fine (well, other than the fact that it runs almost constantly, but still it does keep the indoor temp at 68 or 69 as I set it, and it uses a half of energy to accomplish that when compared to aux heat). However, it hasn't dropped below 30F yet since I changed the settings so we'll see how well it does when the temps drop even more; I'll definitely be monitoring it closely and may bump it up to 30F or even 35F if necessary. This should still be a huge improvement in cost savings when compared to 45F originally set by the installer because roughly 70-80% of the time from November until March the temps where I live seem to be between 30F and 45F (with an occasional dip into 20's and hardly ever into 10's) so even if I bump it up it means that I'd use some aux heat no more than 30% of the time (and most likely not in the full capacity).

    I just hope that almost constant running of the unit will not cause a premature failure...

    BTW - is there anything special that needs to be done maintenance wise when operating the unit for such extended periods of time (i.e. more frequent service, or something similar)?

    Quote Originally Posted by mark beiser View Post
    These settings are only for fresh air intake, if you do not have a fresh air intake duct, with a damper controlled by the thermostat, you can turn this stuff off, or leave it alone.
    I don't have any of those options.

    Thank you one more time for all your help!

  10. #10
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
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    I would not be concerned with the long run times, it is probably in first stage. If you hear the unit going into defrost frequently then I would be concerned. with the 16i if you listen carefully you can hear the fan speed increase and decrease as it changes from first stage to second and back to first. If you can not discern the sound level change tape a strip of paper over the register and you will be able to see the movement.

  11. #11
    Join Date
    Nov 2007
    Posts
    43
    ....also if you have a 3 Ton heat-pump Air Handler system with BAYHTR1415BRKR and have doubts about a flaky installer I would recomend verifying that your air handler's dip switch minimim air CFM setting is correct. BAYHTR1415 needs 1300-1400CFM minimum with your air handler when the heat pump is operating with the strip heaters. Thats a pretty high CFM for a 3 Ton unit and might explain the installers strange logic of locking out the HP at such a ridiculously high temperature. Check to see that dip switches 7 and 8 on the air handler are both set to OFF. (Actually I'd be interested to know from a serious TRANE guy if you'd actually get 1400CFM with the 037AH set to operate with a 3 Ton ODU.)

  12. #12
    Join Date
    Jan 2007
    Location
    Granger, IN
    Posts
    49
    The 45 degree setting is ridiculos. You did the right thing by looking into the setup. I live in northern indiana were the temps can range from -'s to mid 30's in winter. We only set the comp lockout on duel fuel systems and even then we set it a 35 to avoid numerous defrost cycles, as for the unit running along time just imagine if you were cooling on a 95 degree day the unit would run just as long, don't sweat the run times its supposed to run.
    I am here to provide you with every option I know of but if you make a stupid decision don't blame me.

  13. #13
    Join Date
    Nov 2007
    Posts
    15
    Quote Originally Posted by second opinion View Post
    I would not be concerned with the long run times, it is probably in first stage. If you hear the unit going into defrost frequently then I would be concerned. with the 16i if you listen carefully you can hear the fan speed increase and decrease as it changes from first stage to second and back to first. If you can not discern the sound level change tape a strip of paper over the register and you will be able to see the movement.
    I thought the XL16I in Comfort R mode ran 50% for the first minute, 80% for the next 8 or so, and then 100% until the call for heat is satisfied?

    This is not the case? I see in the post from second opinion it will go back and forth from first to second stage as needed?

    Thanks for the clarification.

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