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  1. #1
    Join Date
    Jul 2006
    Location
    Loganville, Ga.
    Posts
    10

    Smile Is this normal heat pump behavior?

    I've had a couple of similar situations that concern me. A month ago and again this morning (about 45 degrees out this morning, colder last month) I heard the heat pump repeatedly kicking on and off. Almost like it couldn't start but would keep trying? The stat shows 73 inside and setpoint is at 75, also says heat is on. But the heat pump is not running and no air is blowing. This morning I turned the stat to 76 and the aux heat came on and got the stat to set point in a little while. I turned it down later since it was too warm and it has been behaving normally since.

    The first time my HVAC folks came out a month ago, they ran it through its paces and all looked good. They're going to come back today and check it again. My question is if this seems normal or if I'm just a crazy home owner that is jumping the gun by calling them when things seem to get back to normal in a little while. I want to be prudent in notifying them of a possible issue but don't want to call them unnecessarily. They're a good company and have been quick to help me with same day service.

    Sorry for the long post but wanted to give all the info I could. I'm just wondering if this behavior rings a bell with anyone.

    I have an 18month old Trane 2 zone system consisting of the following:

    TUD100R9V5 XV80 furnace with two stage heat and variable speed indoor blower motor.
    Aprilaire model 2200 hi efficiency air cleaner
    RXC054S3 hi efficiency indoor coil.
    4TWX4048 4ton XL 14i deluxe hi efficiency heat pump. System uses R410 refrigerant.
    New Refrigeration line set.
    EWC (2 zones, one up and one downstairs)Zone Control panel.
    Motorized zone dampers.
    Barometric bypass damper.
    Hart & Cooley A-618 adjustable deflection registers.
    TCONT803 VIsion Pro tstat with summertime humidity control. One thermostat upstairs and one downstairs.


    Thanks for any responses.

    And Happy New Year!!!

    Daninga.

  2. #2
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    ok, so you have a dual fuel sytem

    from what you say, yes you are having a problem with the heat pump portion of your dual fuel system

    call in the pro's, while they are there, after they fix your heat pump problem

    make sure they have the balance point set properly



    .

  3. #3
    Join Date
    Jul 2006
    Location
    Loganville, Ga.
    Posts
    10
    Quote Originally Posted by Airmechanical View Post
    ok, so you have a dual fuel sytem

    from what you say, yes you are having a problem with the heat pump portion of your dual fuel system

    call in the pro's, while they are there, after they fix your heat pump problem

    make sure they have the balance point set properly



    .
    Thanks for the response, Airmechanical. You are correct about that the problem is with the heating, sorry I wasn't clear in my description of the problem. I had called them this morning and a tech arrived about 2pm. I must say they're very responsive and I'm happy with them.

    While he was testing the stat, he noticed the aux (gas) heat coming on at a 2 degree difference. It's supposed to come on at a 3 degree difference. Bottom line is that he checked the indoor and outdoor units and decided to "change the cycles per hour for aux heat from 5 to 3 because 2nd stage heat was coming on too much". This is the description of work that was written on the service order. He did say that 5 was their default but that we'd try 3. He thought that the heat pump was kicking on and off because the CPH of 5 was too agressive.

    Is the CPH what you mean by the balance point?

    At any rate, I'll see how it goes since tomorrow morning will be in the mid 30's and the next two days will be in the low to mid 20's.

    Thanks.

  4. #4
    Join Date
    Dec 2007
    Location
    oregon
    Posts
    885
    What kind of zoning are you using? Is it the Trane brand "comfort link?" Does your zoning Have a supply plenum air temp sensor? What is the duct size for each zone supply trunk? CPH stands for "cycles per hour"
    Genius = The guy who can do anything...except make a living!

  5. #5
    Join Date
    Dec 2007
    Location
    oregon
    Posts
    885
    There are no settings in the tcont803 that allow back up heat to be called for unless the outdoor heat pump cutout temp has been reached. The heatpump should stay on as the main source of heat(untill compressor lock out temp is seen by the outdoor sensor) That is unless you have an external fossil fuel control. THe 3 CHP is for two stage fossil fuel systems and the 5 CHP is for single stage fossil fuel systems. There should be a minimum of 5 minutes off time for the compressor. Have your tech double check all of the settings in the installer set up of the thermostat. You may have a control wire issue or internal fault in the heat pump.
    Genius = The guy who can do anything...except make a living!

  6. #6
    Join Date
    Dec 2007
    Location
    oregon
    Posts
    885
    Sorry about my first post, It just dawned on me that Trane has its own stats for their zoning( duh) I've installed dozens of "comfort link systems by Trane). So you must be using a Honeywell or other brand.
    Genius = The guy who can do anything...except make a living!

  7. #7
    Join Date
    Jul 2006
    Location
    Loganville, Ga.
    Posts
    10
    Quote Originally Posted by geodude View Post
    Sorry about my first post, It just dawned on me that Trane has its own stats for their zoning( duh) I've installed dozens of "comfort link systems by Trane). So you must be using a Honeywell or other brand.
    Thanks for the response, geodude.

    Actually, that's what he did. He went through all of the settings and changed the 'cycles per hour' on both stats, upstairs and downstairs.

    I believe Trane just rebrands the Honeywell stat if I'm not mistaken. Thus far the only thing I've noticed that's different is the system runs longer now after getting to set point. For example, now once it reaches the set point, the inside temp is 77 and the set to temp is 77, it still runs for 10 -20 minutes longer. I don't think that's good, it seems a waste of energy. It seems that if it reaches set point then it should stop the heat rather quickly like it used to. Perhaps by reducing the cycles per from 5 to 3, the system runs a longer cycle??? Is that how the cycles per hour work?

    Is the balance point mentioned by Airmechanical and the cycles per hour the same thing?

    Thanks.

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,764
    Changing the CPH changes the length of the on time, and the off time.
    It will take a while for the stats to relearn the house.

    Balance point is not related to CPH.
    Heating Balance point is the OD temp that the HP can't maintain set point anymore.
    Economical balance point is the OD temp that it becomes cheaper to use teh aux heat then the HP.
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  9. #9
    Join Date
    Dec 2006
    Location
    Middle Tennessee
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    it sounds like you really want to know all the options of your paticular t-stat

    your best bet is to get an installation manual and a owners manual on your stat

    read it a bunch of times, then if you have questions after that we will try to answer!

    some of the t-stats that are on the market can be quite complex for first timers

    before i wired and set up parameters on my first honeywell 8000 t-stat

    i spent the better part of 1 night reading about it first

    there are tons of combinations on these stats

    after 3 years and many different parameter changes, i finally got my 8000 working (exactly how i want)



    .

  10. #10
    Join Date
    Jul 2006
    Location
    Loganville, Ga.
    Posts
    10
    Quote Originally Posted by beenthere View Post
    Changing the CPH changes the length of the on time, and the off time.
    It will take a while for the stats to relearn the house.

    Balance point is not related to CPH.
    Heating Balance point is the OD temp that the HP can't maintain set point anymore.
    Economical balance point is the OD temp that it becomes cheaper to use the aux heat then the HP.
    Great explanations beenthere. My main concern on the changing of the CPH has been the extended runtimes that I'm now seeing. Once the stats relearn the house, as you noted, maybe it'll run more like it did before the tech changed it. So I should be patient while the stats relearn the house and not be so concerned with the extended runtimes??? I might be a little cheap in that I think I see dollars flying away with the extended runtimes.

    So the economic balance point is just an arbitrary temp that one sets to lock out the heat pump and force the aux heat on? For example, one can set a 20 degree (or any number) balance point in the stat somewhere. On my system there is no outside stat or sensor.

    Very interesting. Going over my notes with my contact at the Heating and Air company, I find that I was told not to worry about the outside temp. The heat pump will turn to aux when it finds it can't keep up. Maybe it's setup to turn on aux if it falls behind x number of degrees? I've never worried about it, the heat pump runs almost all of the time. It's rare to see aux on and that's probably more due to defrost cycles than to outside temp.

    Airmechanical: The interest in the stat is mainly intellectual, I'm not a DIY and wouldn't try to be. A man needs to know his limits. I'm a systems analyst so I do enjoy reading manuals and I may do that. But I'm just trying to learn enough to understand the processes involved in this quite large investment. Not to master but only to have a basic understanding.

    One last question to you pros if you don't mind: under what type of conditions do you find that you'd want to change the CPH? What what type of specific conditions would prompt you to make a change to the CPH?

    So I think I'll try to relax and not worry about the runtimes for awhile and see how the stats adapt. I'll monitor the runtimes some, of course, to have a baseline that I can compare later runtimes to. The tech told me that this was just something we could try and to call them back as needed. They've provided good service to me. they are my guys!

    I appreciate very much the reponses from all of you.

  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,764
    At 3 CPH you will see a longer run time then you did at 5, and a longer off tiem when it shuts off.
    But it won't use more electic.
    It will use stlightly less. It uses more electric when it cycles on and off a lot.

    Ignore it for afew days, and you'll like the temp better then when it was at 5.
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  12. #12
    Join Date
    Dec 2007
    Location
    oregon
    Posts
    885
    As norm it is not reccomended to change the CPH. Trane does brand the Honeywell stats, but on "their" zoning stats they have a 4 wire proprietary model that uses a network type comunication, instead of switching low voltage signals. I would get an owners manual and set up guide, read it for a few days, then ask your installing contractor about making any changes. If you try to change things without proper understanding you can really throw the system out of whack.
    Genius = The guy who can do anything...except make a living!

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    He has an EWC zone panel, not a Trane.
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