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  1. #14
    Join Date
    Feb 2009
    Location
    Portland OR
    Posts
    2,029
    Corrections XL16i runs at 60% of capacity in low stage with 80% of airflow, high stage is 100% airflow and capacity. I am not familiar with that zoning but they should have a two stage zone panel that will only operate stage 1 cooling when 1 zone is open and will operate full capcity when more than half the zones are open. You might need a second set of eyes to look at the wiring.

  2. #15

    Compressor capacity changes

    SkyHeating
    "Corrections XL16i runs at 60% of capacity in low stage with 80% of airflow, high stage is 100% airflow and capacity." ----> Ok on there being 2 stages, or is it really steps that you mean with this particular xl16i unit.. But back to the question of how does this go back and forth between them and is there a control to do it.. Looking at the schematic and wiring diagram, unless I'm not seeing it clearly, I do not see a control device connection to change 'something' at the compressor.. Maybe there is none other than on/off and it self senses what capacity to be using somehow..???

    "two stage zone panel " ----> Well I would completely agree with that 'If it were truly a 2 stage unit", which perhaps it is not.. (And maybe should have been?)

    "second set of eyes to look at the wiring"----> Well I did that before looking here for some assistance.. I called the original installer.. Technician came out and went through the system, zone dampners and all.. Never did take the time experience what I had originally called about, told me it was a bad t-stat and wanted $400 bux to change it, over and above the cost of the t-shooting call charge.. I basically said no tnx, as I have 3 identical t-stats, (different zones), and they control identically in that position. (Besides I can buy the identical t-stat for less than 25% of his charge.)

    Please advise on the load capacity changing of the compressor, all things being equal..

    Tnx,
    Bob

  3. #16
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,878
    What is the brand and model of the zone system

  4. #17
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    990
    Quote Originally Posted by Southern Mech View Post
    when you have 1 compressor and it loads to different capacities, is that not step loading?
    Its a matter of semantics I guess. Mechanically its an unloader but in terms of how its controlled, its staged to me. Haven't seen you around Southern Mech, welcome back.

    To the OP the staging for the compressor is determined only by the t-stat. The compressor capacity is split roughly 67/100% The blower is also controlled by the thermostat although there are some blower settings that involve an internal time based function to vary its speed.
    Quote Originally Posted by k-fridge View Post
    The laws of physics know no brand names.

  5. #18
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,689
    Quote Originally Posted by SoFlaDave View Post
    Its a matter of semantics I guess. Mechanically its an unloader but in terms of how its controlled, its staged to me. Haven't seen you around Southern Mech, welcome back.

    thanks SoFla, been against the wall. Thanks for the backup on the ''stage'' question, I went a little too technical for a general homeowner section.
    To the OP the staging for the compressor is determined only by the t-stat. The compressor capacity is split roughly 67/100% The blower is also controlled by the thermostat although there are some blower settings that involve an internal time based function to vary its speed.
    To the OP some Model and Serial #'s of equipment and stats, zone control and your general issue may help us resolve what you are getting at a little faster and acurate.
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  6. #19
    Join Date
    Dec 2002
    Location
    Toledo, Ohio, United States
    Posts
    12,921
    Quote Originally Posted by SoFlaDave View Post
    Its a matter of semantics I guess. Mechanically its an unloader but in terms of how its controlled, its staged to me. Haven't seen you around Southern Mech, welcome back.

    To the OP the staging for the compressor is determined only by the t-stat. The compressor capacity is split roughly 67/100% The blower is also controlled by the thermostat although there are some blower settings that involve an internal time based function to vary its speed.
    Twilly says great way to describe it.

    Twilly says Southern Mech is correct in the way the compressor operates, but Trane does market it as a two stage piece of equipment.

    Twilly's apologies to Southern Mech as he is a very knowledgeable tech.
    No Heat No Cool You need Action Fast

  7. #20
    Join Date
    Nov 2003
    Posts
    19
    Hello -

    I am owner and just installed a 16i in central texas and after some install snafus (look for my other thread) I can tell you that the unit is exceeding my expectations (grand total 5 days run time, 5 days MTBF :-).

    Here is my situation:

    - approx 2000 sq ft, 2 story
    - hot garage beneath one bedroom (I insulated the metal garage door, myself if you are interested I can tell how to do it, it is easy and very effective)
    - hip roof, lower pitch (bakes)
    - lots of windows, solar screens
    - lots of shade, but morning to aft. full exposure on garage and front of house.
    - high ceilings
    - 4 ton unit
    - previous years peak elect bill $140 during month of 100+ so we are conservative with energy.

    It has been 102 to 105 during these 5 days.

    We keep tstat at 77 to 78. R.Humidity has been about 40% to 45% inside, 30-35% outside @ 100+F. Edit: just checked and it is 34% RH inside now.

    The unit runs on low most of time, it is barely noticeable. Starting in evening, roof/attic heat starts accumulating inside. At this point unit will run on high for a few minutes and switch to low. In this house, the hottest up stairs is around 7PM and duty cycle shifts to high side around then. I don't know if it's oversized, or just the way it works or unit is coasting because it runs on low during day. May also be tstat has some smarts.

    Very quiet inside on low, you hardly notice it (no more blast of icy air roaring out). Outdoor unit is quieter than last unit, but not remarkably so.

    The upstairs has definitely been cooler than in past, maybe because it runs on low a bit more often. Additionally if we run fan "on" instead of auto, it runs on low and almost equalizes temp. between up and down at about 3 to 5% increase in humidity. Going upstairs used to be like walking into blast furnace.

    I decided we were good candidate for two stage, then picked the installer who seemed easiest to work with and down to earth. Unfortunately, we did have some snafus, but the installer made good on each one. My other thread lists one about humidity that was simple wiring error.

    There are a few variables to tune the system - so it may take a few iterations to get things right.

    I had a number of people tell me a two stage would just run on high here, or it would run on high and shut off, but that doesn't seem to be true at all in our case.

    Some have said 16i isn't best at removing humidity, I can't comment on that because Austin is dry right now.

    Assuming unit doesn't blow up tomorrow, and with all of 5 days behind us, we are REALLY impressed. It was expensive, but if it holds up over time, definitely worth it for here in Austin for low noise and hopefully good efficiency.

    So if anyone reads this in central texas and is thinking about 2-stage, for us at least, it is revolutionary. Costs are high, hope over time costs come down and quality goes up.
    Last edited by bobl; 08-05-2011 at 10:46 PM. Reason: update humidity

  8. #21

    Compressor capacity changes

    To ALL the fine posters....

    Tnx for previous info and it helps me to understand better. See if I understand this correct now.. I will also follow with equip listing after..

    The T-stat only is 'normally' what will control the 2 'STEP' XL16i compressor for changing from low to high capacity and back again, as well as control the blower speeds. (Note I said STEP, not stage). But this would be a 2 STAGE t-stat to call for more or less cooling, correct? If I read the schematic correctly, when cooling is initially called for, the blower should turn on in lower speed and the compressor should also turn on in step 1, (Lower capacity). Then if/when additional cooling is called for by T-stat, an additional signal is sent from the t-stat to the compressor solenoid this time to increase its capacity.. The blower also speeds up.. As the t-stat becomes satisfied it starts to step down until it shuts off or has to go back up.

    Now, I believe that is what 'normally happens? Correct me if I'm wrong please.!

    Now, here is what my system actually is..!!

    Take a deep breath as I got windy here.. Go slowly..

    ************************************************** ************
    Furnace
    Trane XV90 Model# TDY120R9V5W5 (2 Stage Heating)
    Serial# 609430U7G

    Air Conditioner
    Trane XL16i Model# 4TTX6060B1000AA (2 Step Cooling ?)
    Serial# 5505ECG2F (W92)

    Zone Controller
    EWC Model# NCM 300 (2 Stage Heating Single Stage Cooling)
    (Only 2 Zones installed and controlled)

    T-Stats (2Units)
    Luxpro Model# PSPA722 (2 Stage Heating and Cooling Capable)

    ************************************************** ***********
    Problem I see........

    Here is how the system operates.......
    1.) T-stat calls for cooling... Blower starts to run in lower speed.
    2.) T-stat is flashing saying in cooling mode, but nothing running at all at the condenser. (T-stat contact for 1st stage is made but no wire is connected to that terminal at all.
    3.) T-stat finally says need more cooling capacity... Blower increases in speed, 2nd stage contact is also now made and compressor comes on and we get cooling.. (Not sure yet if that is low or high capacity of compresser, as I have not looked at that wiring yet.)
    4.) 2nd stage t-stat becomes satisfied with temp and drops out leaving 1st stage running yet.. (But this is only the blower as the compresser dropped out w/the 2nd stage)... This will continue to run like this until temp of stage 1 t-stat is satisfied and everything shuts down, or stage 2 of t-stat calls for more capacity again..

    (Remember, I said 1st stage of t-stat has no wire going to it... This EWC zone controller only has single stage cooling control.. I believe that means on/off, not step 1/2. It requires a SINGLE stage t-stat, and I believe that's why the no connection to t-stat 1st stage for the compresser.)

    So I think the compresser is just on and off being driven by the 2nd stage and I am not getting the anything in the first stage other than blower.. So, I don't believe the compresser changes its load capacity..

    I believe that perhaps the wrong zone controller was initially installed.. I believe that maybe the "EWC Model UZC4 Zone Controller" would have been the correct controller to use.. I also know that 2 complete sets of wires are in the wall for each T-stat back to the furnace, but only one set was used.. Makes me wonder if that was the original intent...??

    Please advise.. Hope I didn’t get too windy here.. Tnx..

    Bob

  9. #22
    Join Date
    Sep 2009
    Location
    Kennesaw, GA
    Posts
    618
    Here's some technical info on your outside unit:

    http://www.bbheating.com/custres/doc...-103-1-.01.pdf

    http://www.ebuild.com/product-detail...ral/519829.hwx

    The ebuild and also Tranes website says its 2 stage cooling.
    I can also see your furnace is a two stage cooling/heating from the manual:

    Check page 11 and page 14.
    http://www.aireng.com/clientuploads/...urnace/tuy.pdf

    You are kinda on the money : The problem is your zone controller is 1 stage cooling and also your thermostat:

    Info on your zone controller :
    http://www.ewccontrols.com/user_manuals.htm#NCM-300

    Your right you need a other zone controller that has 2 stage cooling/heating. And as all the pro's here always suggest as of thermostat wise : Honeywell VisionPro IAQ

    Your installer kinda screwed up and used the wrong equipment with the AC part of your unit.

  10. #23
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    990
    The stage one signal should operate the contact to turn the compressor on and the stage two signal operates a solenoid in the already energized compressor.

    The tstats are slaves to the zone control and if its single stage cooling only, you're not getting normal operation. Installer error at its finest. Since its been roughly 5 years since it was installed according to the serial numbers, you may have a tough time getting the installing contractor to cover the replacement of it to be honest. I hope everything turns out, keep us posted.
    Quote Originally Posted by k-fridge View Post
    The laws of physics know no brand names.

  11. #24
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,428

    Unhappy

    Quote Originally Posted by Twilly View Post
    Twilly says get in touch with Trane and tell them to change the literature and website, cause apparently they didn't get the word from you.
    Also, need to call LENNOX

    http://www.lennox.com/resources/faqs...stage-cooling/

    & probably a "few" other companies.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  12. #25
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,689
    Quote Originally Posted by dan sw fl View Post
    Also, need to call LENNOX

    http://www.lennox.com/resources/faqs...stage-cooling/

    & probably a "few" other companies.
    I say you need to learn your product better, the way the compressor works is a''step load''



    I alway's carry sales brochures for homeowners, they hold so much more information than a technical manual that a ''Factory '' trained mechanic would ever have.

    I have already tated and agreed I went way to ''deep'' for this discussion.
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  13. #26

    The home system...

    Well, I would like to thank ALL of you for your inputs.. Many things have been clarified as to the terminologies, why for's and how to's so as to satisfy my own suspicions and thoughts.. I feel very certain as to how this system SHOULD be operating, and can see that there is NO WAY that it can, as currently installed..

    I now must go back to my GC who oversaw all this as well as the original HVAC supplier/installer and bring this matter up to their attention.

    Again tnx for ALL of your assistance.. I may be back for more, who knows..

    Bob

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