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  1. #1
    Join Date
    Mar 2007
    Posts
    55

    Trane XL16i running all the time at cold temperatures - Is this normal?

    Hi! Last May I got a Trane XL16i heat pump installed and so far have been very happy with it. With it getting colder outside, I have noticed that it runs constantly if the temperature is down in the mid 20's or lower and wanted to see if that is normal when having the house set at 68 degrees. I have the Trane thermostat (the 802) with the outdoor temperature sensor. With having a thermometer at one of the vents, I can see that it switches from the first stage (With outside temperatures in the low 20's, I see upper 70's coming out of the vents) to second stage (With outside temperatures in the low 20's, I see mid to upper 80's coming out of the vents) occasionally. Then after several minutes in second stage, it kicks back down to first stage. I guess I would have expected it to stay in second stage as long as is needed and then have the air completely kick off once the desired temperature is reached (like my old heat pump did). If I raise the temperature a couple of degrees to kick on the auxillary heat banks, temperatures get above 100 quickly. But then after several minutes, the air kicks back to a lower stage instead of having the air kick off completely. Is what I am seeing normal operation with this heat pump? Thanks in advance for any responses!

    Aaron

  2. #2
    Join Date
    Jan 2007
    Location
    Sioux Falls, SD
    Posts
    9

    heat pump stats

    That's the problem with most heat pump thermostats when the temperature drops below the balance point.

    I use two different solutions for my customers to chose from. One is to use an outdoor sensor or stat to bring on one bank of electric heat when the temp drops below 25 or 30 degrees along with the heat pump. The other solution (and the easiest and cheapest) is to just use a Braeburn model 3200 (non programmable) or model 5200 (programmable) thermostat to run the system. With these stats and an all electric system the heat pump will always run on first call for heat but if it fails to maintain the set temp and the house continues to get cooler the second stage will call for the electric heat strips to come on and then KEEP THEM ON UNTIL BOTH CALLS FOR HEAT are satisfied, at which time the system will shut off. On the next call for heat the heat pump starts by itself and the cycle starts over.

    This system is an easy one to use and still take advantage of the heat pumps ability to produce heat at colder temps while keeping the customer happy with warmer supply temperatures.

    Hope this helps.

    Kilowattdiver

  3. #3
    Join Date
    Sep 2003
    Location
    McKinney, TX
    Posts
    470
    is the trane 802 t-stat the touch screen one? if so that t-stat can be set to lock out heat pump at a certain temp and bring on electric heat strips. this would be the best option. Have your installer set this up.

  4. #4
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Why is it a problem if the heat pump is maintaining setpoint? Why do you want to waste electricity?

    If your customers are complaining about cold discharge temperatures, you need to select registers that don't throw air on them. You also need to educate your customers on the proper operation of a heat pump system.

    To the OP, there is nothing wrong with your heat pump running as you describe. The system is maintaining temperature in the home. As it gets a bit colder, you will see it staying in high stage longer. Eventually, it will start cycling AUX heat while the compressor continues to run on high stage.

    I have a 5-stage HP system in my home. Once it's in the 20s the HP never stops running. When it's in the mid to high 30s, the heat pump may actually stop from time to time. It depends on the wind and how often we open the doors.

    Heat pump systems are not designed for you to stand on the grill to warm yourself. As you've noticed, they have air temperatures that are less than your skin temperature.

    Enjoy the low cost heating!
    Perhaps you should have read the instructions before calling.

  5. #5
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by jrbenny View Post
    I have a 5-stage HP system in my home.
    5 stages?, does that mean 2 stages heat pump, with 3 stages of 5 kw each


    .

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,935
    A 2 stage stat wouldn't help either. Thats a 2 stage outdoor unit, plus strip heaters.
    Better known as a multistage stage heat pump.

    Your current stat can be set for the second stage to satisfy the heat call if you really want it to.
    Just adjust the CPH of the second stage to less then the first stage CPH.

    But its doing what it is suppose to do.
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  7. #7
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Quote Originally Posted by Airmechanical View Post
    5 stages?, does that mean 2 stages heat pump, with 3 stages of 5 kw each


    .
    Keyword...

    system


    Yes, you are correct.
    Perhaps you should have read the instructions before calling.

  8. #8
    Join Date
    Jan 2007
    Location
    Arkansas NWA
    Posts
    33
    jrbenny:
    If the system NEVER shuts off than yes there is a problem. The unit should be bringing on stages of aux heat strips as needed than bring the room up above desired setpoint than cycle off. Hopefully the home is insulated well enough and the equipment sized properly to maintain and or get to desired temp! Have the tech come back and reprogram the stat so that this happens.
    Good Luck

  9. #9
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Nope.

    If the system is below the balance point of the structure, then the heat pump should continue to run. Modern thermostats have enough control built into them to prevent overshooting first or second stage. So, the aux heat is secured before satisfying the call for heat pump.

    With it getting colder outside, I have noticed that it runs constantly if the temperature is down in the mid 20's or lower and wanted to see if that is normal when having the house set at 68 degrees.
    Mid 20's or lower is most likely below balance point of the structure.
    Perhaps you should have read the instructions before calling.

  10. #10
    Join Date
    Mar 2007
    Posts
    55
    As far as the system shutting off...As soon as the outside temperature reaches about 30 degrees, it shuts off once the set temperature is reached. So it sounds like the system is running like it should. Being that it runs differently than my old heat pump does, I just wanted to make sure. Thanks to all who responded..

  11. #11
    Join Date
    Jan 2007
    Location
    Arkansas NWA
    Posts
    33
    If the unit is running below the balance point without aux heat it is a waste. Once you reach that point of 1/btu for 1/btu and the compressor continues to run your not gaining anything. You than need aux heat to overcome this point. It sounds to me the aux heat is not coming on soon enough. These are just opinions would love to see it first hand.

  12. #12
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Not an attempt at being argumetative...

    You must be well below zero °F to get a COP less than 1.
    Perhaps you should have read the instructions before calling.

  13. #13
    Join Date
    Sep 2003
    Location
    McKinney, TX
    Posts
    470
    this is a stupid thread. At my house I have a heatpump with same t-stat and an outdoor sensor. I noticed that at below 30 degrees is doesnt warm the air very well, so i set it up to bring on backup heat in those situations. Since I live in dallas we dont get below 30 degrees very often. So anything above 30 degrees the stat is set up to not allow electric heat to come on. This is common practice, I dont know why everyone in arguing.

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