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Heat pump aux heat constantly running with Ecobee 3

Issue from last year that I didn't get resolved and want to as the winter is approaching this year.

I have an Ecobee 3 installed with a 3 1/2 ton heat pump for a 2750 sq ft home.

Have the thermostat set at around 72 degrees with outside temps ranging between 45-55 degrees the last few days.

Everyday there is a message about aux heat running in excess of 180 minutes for the last 24hrs.

  • auto heat/cool enabled
  • heat/cool min delta 5 deg
  • compressor min cycle 300 secs
  • compressor min outdoor temp 35 deg
  • ac overcool disabled
  • aux heat max outdoor temp 68 degrees

Answers

  • kevin_mcckevin_mcc 61455Member
    edited October 2016 Answer ✓

    I would change aux heat max outdoor temp 68 degrees to something lower. This setting is to prevent AUX running if the heat pump is fully capable of heating the home quickly. I believe I have mine set to 40 degrees, maybe with an older heat pump you may want that a bit higher.

    Also compressor min outdoor temp 35 deg should be set lower if you have a newer heat pump. At 35 degrees, any cooler outside and the heat pump won't work at all. My Amana heat pump makes heat down to -10 degrees F! Unfortunately for me Ecobee can only go to 0 degrees F which is where I have mine set. Set close to point where you feel heat pump is not heating well and you just want AUX to work. Check with manufacturer how low it will go. Use Aux Heat Simultaneous Operation if can and are really thrifty. See below for more details.

    I would also change heat/cool min delta 5 degrees to 1 degrees. Better for heat pump to run more, bring temp up and turn off quicker. The large delta may cause the the heat pump not to finish the job quick enough and the AUX turning on. The goal is to minimize AUX usage at all cost, especially if you have electric AUX.

    You may want to set the following as well.

    If you can, you might want to use Aux Heat Simultaneous Operation. This will let the AUX assist the heat pump in heating. Your heat pump coil should be upstream from the AUX heat, example in an up flow furnace the coil in the bottom and AUX heating in the top.

    Compressor Reverse Staging allows you to go back to Stage 2 and Stage 1 from AUX as set points are reached.

    Compressor Stage 2 Temp Delta I have 1 degrees, if you have a 2 stage heat pump.

    Compressor to Aux Temp Delta I have 3 degrees, if using a single stage maybe 2 degrees is better choice.

    My setup furnace will run a lot when really cold, but in my case AUX is a 10 kW electric and the heat pump is less than 2 kW. As long as my heat pump is more than 100% efficient in making heat, I am running the thing. At 0 degrees F my heat pump is 176% efficient!

    Also make sure you outdoor and indoor coils are clean! If they are dirty your system will run poorly. Also make sure you freon charge is correct.

    Also check you Home IQ data to see how the heating is behaving.

    Jhobbes
  • Thank you. I will make these adjustments this evening.

  • BellyUpFishBellyUpFish AlabamaMember

    Did the suggestions above help you out?

    I'm having some issues with one of our EcoBee's.

    New house we just finished building, EcoBee's are the only thermostats in the house. My upstairs unit seems to be working great. The main level is not heating or heating very little.

    Had the temp set to 71* last night and it was holding until some point in time during the evening. Woke up and I was indicating 65* at the thermostat.

    I can't get it to heat at all now, via my phone app. I'm not home so I need to look and see what happens when I get home.

  • kevin_mcckevin_mcc 61455Member

    Had an interesting discussion with Ecobee support. Found some things I don't like.

    1. If you lose WiFi even for a moment, the Ecobee does not know outdoor temp until the WiFi reconnects. Why they do not cache/buffer this for up to 10 minutes or so I don't know.

    2. If you have Compressor Reverse Staging on, the Ecobee uses some sort of algorithm based on deltas and up coming temperature to determine which stage to start out at.

    Reason I found this out was I have the AUX locked out until 35 degrees, yet the thermostat called for Stage 2 and AUX when it was 50 degrees outside. I guess the WiFi was out just at that moment for about 3 minutes... I also did not realize the Compressor Reverse Staging used some algorithm, and I'd rather it just used my deltas and no algorithm.

  • kevinmcckevinmcc Macomb, ILMember

    After fixing WiFi and giving Ecobee a few weeks, working like before. I am back to being happy.

  • 50ae50ae mckinney, txMember

    I had a problem where Aux Heat went on for 8 hours straight the other day but did not warm the house at all. I called my AC guy and he did some rewiring at the unit itself so that the aux could be controlled from the thermostat as it wasn't really on at all the whole time.

  • kevinmcc,

    Sorry for the delay in getting back with you. The weather in this part of Texas has been down in the mid 20's the last couple days which made me remember to respond.

    I made all of the suggestion you recommended and I have not gotten any messages about the auxiliary heat running in excess of 180 mins.

    I have the temp set at 73 during the day and 71 overnight with it heating up to 73 first thing in the morning.

    Thanks again for the advice. It seems to have done the trick!

  • @Jhobbes said:
    kevinmcc,

    Sorry for the delay in getting back with you. The weather in this part of Texas has been down in the mid 20's the last couple days which made me remember to respond.

    I made all of the suggestion you recommended and I have not gotten any messages about the auxiliary heat running in excess of 180 mins.

    I have the temp set at 73 during the day and 71 overnight with it heating up to 73 first thing in the morning.

    Thanks again for the advice. It seems to have done the trick!

    What were the suggestions he made? I'm curious. I get these AUX running over 180 minutes a lot...in Arkansas.

  • these> @timurray2000 said:

    What were the suggestions he made? I'm curious. I get these AUX running over 180 minutes a lot...in Arkansas.

    These were the changes he recommended:

    "I would change aux heat max outdoor temp 68 degrees to something lower. This setting is to prevent AUX running if the heat pump is fully capable of heating the home quickly. I believe I have mine set to 40 degrees, maybe with an older heat pump you may want that a bit higher.

    Also compressor min outdoor temp 35 deg should be set lower if you have a newer heat pump. At 35 degrees, any cooler outside and the heat pump won't work at all. My Amana heat pump makes heat down to -10 degrees F! Unfortunately for me Ecobee can only go to 0 degrees F which is where I have mine set. Set close to point where you feel heat pump is not heating well and you just want AUX to work. Check with manufacturer how low it will go. Use Aux Heat Simultaneous Operation if can and are really thrifty. See below for more details.

    I would also change heat/cool min delta 5 degrees to 1 degrees. Better for heat pump to run more, bring temp up and turn off quicker. The large delta may cause the the heat pump not to finish the job quick enough and the AUX turning on. The goal is to minimize AUX usage at all cost, especially if you have electric AUX.

    You may want to set the following as well.

    If you can, you might want to use Aux Heat Simultaneous Operation. This will let the AUX assist the heat pump in heating. Your heat pump coil should be upstream from the AUX heat, example in an up flow furnace the coil in the bottom and AUX heating in the top.

    Compressor Reverse Staging allows you to go back to Stage 2 and Stage 1 from AUX as set points are reached.

    Compressor Stage 2 Temp Delta I have 1 degrees, if you have a 2 stage heat pump.

    Compressor to Aux Temp Delta I have 3 degrees, if using a single stage maybe 2 degrees is better choice.

    My setup furnace will run a lot when really cold, but in my case AUX is a 10 kW electric and the heat pump is less than 2 kW. As long as my heat pump is more than 100% efficient in making heat, I am running the thing. At 0 degrees F my heat pump is 176% efficient!

    Also make sure you outdoor and indoor coils are clean! If they are dirty your system will run poorly. Also make sure you freon charge is correct.

    Also check you Home IQ data to see how the heating is behaving."

  • Wow. Good info.
    Ecobee needs to add manufacturer data and a "wizard" that asks you a few questions, then configures the system accordingly since it would know what your specific system capabilities are.
    I have no idea how things are configured in my heat pump as far as where the AUX and coil are located.
    You talk about setting it close to point where you feel heat pump is not heating well. I'm not sure how to determine that. If it's 30 degrees outside and it's blowing cold air, then it's not heating well. Or is there more to it?
    I also don't know how to tell if the freon level is good. In the summer, it's pretty simple by checking the air temp and looking at lines to be sweating, etc.
    I'm new to Ecobee. Still trying to figure out why some days, with Smart Recovery enabled, and it's 15 minutes from target time, I'm still 8 degrees away from target temperature. So, 70 degrees by 8:00a and at 7:45a it's 62 degrees. Other days, I might be 2 degrees away at the same time.

  • kevinmcckevinmcc Macomb, ILMember
    edited December 2016

    For me I sat the the AUX Lockout to 35F because because I wanted the AUX to kick before house was freezing pipes, in the case I was away and heat pump failed. In my case I have an Amana ASZ16 which makes safely heat even down to -10F, but at that temperature the amount of heat being made is less than the house is loosing, eventually I will need AUX. Ecobee gives me the ability to lockout the compressor at 0F or disable. I chose disable. I also have an up flow furnace with the coil in the bottom, that lets me run Simultaneous AUX.

    To test if your heat pump is making heat or not you need to measure the return air temp and the supply air temp. Some heat is normally lost in the ducts, but your can measure at supply and return register to get a good idea. A difference as low as 8F means your system is still making good heat. But your home maybe leaking too quickly and you will need AUX. If you can do Simultaneous AUX, run the heat pump and get that 8F of preheat.

    If you have a heat pump, always good to have a servicing in the fall. Have cool cleaned and freon checked. You then know you are good to go for the winter. For me the coils usually get dirty from fluff, seeding of dandelions or cotton wood.

    Can't really say about the smart recovery, maybe system is still learning or has to do with outdoor temp.

  • Ecobee told me today that Smart Recover will not invoke Aux heat. Makes no sense. Smart Recover should recover period. What good is it if it gets so cold that you need Aux?

  • kevinmcckevinmcc Macomb, ILMember

    @timurray2000 said:
    Ecobee told me today that Smart Recover will not invoke Aux heat. Makes no sense. Smart Recover should recover period. What good is it if it gets so cold that you need Aux?

    I wonder if you set the heat pump min temp to the the temperature where your not keeping up if Smart Recovery would actually run the AUX.

  • @kevinmcc said:

    Not sure kevinmcc, they just said it will not invoke AUX for Smart Recovery. I've turned it off because of this. On warmer days, it worked like a charm. On cold days, I would get up and the room was 62 instead of 70. It would come on at 1a and try to get to 70 by 8a. Then at 8a (I guess Smart Recovery was "finished") it would kick on Aux and start warming up.

  • LMRudLMRud MarylandMember

    My observation is like Timurray2000. If Smart Recovery doesn't start early enough and therefore doesn't get to the set point in time, then Aux will come on and finish the job. My system is still in the learning stage.

  • kevinmcckevinmcc Macomb, ILMember

    Smart Recovery won't run AUX at all from my understanding. So basically you just running the current set temp and thresholds. When the set temp changes then AUX will run if below the threshold for AUX. Kind of crazy if you want the temp to be ready at the profile change time as smart recovery is supposed to do.

  • jacksonnjacksonn East CoastMember

    Checkout the LINK below that is posted on Brunswick County EMC (North Carolina) site. LINK is to a Ecobee Configuration document specifically for Heat Pumps. It appears to be an official document from Ecobee, however, I have been unable to find the document on Ecobee WEB-site. Hope this helps. I have setup my new Ecobee exactly like this document recommends and is working fine so far.

    http://www.bemc.org/sites/brunswickemc/files/PDF/Homeowner_Ecobee_HeatPump_FINAL.pdf

    Thanks.

    Jacksonn

  • kevinmcckevinmcc Macomb, ILMember

    Almost how I have mine configured, except I have no Compressor to Aux
    Runtime set. I let my heat pump run and run if the temp is keeping up.

    My Deltas are a bit different as well since I have have 2 stage heat pump.

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