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Compressor Reverse Staging

Has anyone turned on this setting?

The manual states

"If enabled, the thermostat will cycle down from the higher stages so that as it approaches set point it will only be running in
stage 1. The thermostat calculates which stage to start the HVAC equipment in depending on the indoor and set point
temperature delta. As the stage 1 temperature delta is exceeded, the second stage will engage. Once the equipment
has brought the current temperature back to within the heat or cool differential setting, stage 2 will disengage and stage 1 will remain running until the set point is reached."

Stage 1 runs until the thermostat realizes that the desired temp is never going to be reached, Stage 2 kicks in, then Stage 2 turns off and lets Stage 1 finish off the job.

I've switched to this mode temporarily to see if I like it better than the default behavior of calling for W2 based on time.

Comments

  • ZD2342ZD2342 Member
    edited February 2015

    I've had "Compressor Reverse Staging" turned enabled for the last 10 hours and 2nd stage heat has not been necessary.

    I will most likely need to figure out why E3's default behavior is to call for 2nd stage heat so often.

  • jmattionijmattioni Philadelphia, PAMember

    There are several options for the ecobee3 related to how the tstat uses higher stages. You can use stage 2 based on temperature differential from setpoint, based on run time of stage 1 in minutes, or set it to "auto", which is the default. I also found that "auto" used stage 2 a lot. It may be that given enough time it would refine it's use of stage 2, but I instead decided to set values based on temperature differential. Temp sensitivity is set to .5 degree (the default) and stage 2 will now kick in only if temp gets a full degree or more behind setpoint and Aux kicks in if temp gets 2 degrees or more behind setpoint.

    With those settings reverse staging seems to be working as expected. If I look at Home IQ I see that stage 2 will shut off before the end of the cycle and so the cycle finishes with just stage 1.

    A separate question is what's the best logic for using stage 2. The downside with what I'm seeing with the current settings is that a heat cycle with stage 1 only will run for much longer than it probably would if stage 2 kicked in. I guess it'll take some calculations to figure out energy use. If Ecobee were to fully explain how "auto" works and it involves figuring out energy use then I might be convinced to go back to auto settings for using stage 2.

  • Unfortunately, from what I've learned, the auto setting does not update based on the ecobee learning anything. At least that is what I was told by support. The auto setting usually is the first value in the settings.

  • jmattionijmattioni Philadelphia, PAMember

    ZD2342: That's too bad.

    Making it smarter would require more data and a few calculations so it's complicated, but not impossible. It would need to know the power consumption of each stage. For a heat pump that varies based on outside temperature so it would need a table for that.

    It would also need a table of data on typical running times for each stage at different outside temps to achieve, say, a one degree change indoors. This data could conceivably be gathered over time as the system operates. With all that data the most efficient combination of staging to use in a given situation could then be calculated.

    This is probably something an external energy monitoring device could do and then interact with the Ecobee3 via an API to set the parameters.

  • gpzbcgpzbc Colorado, USAMember
    edited December 2016

    How does reverse staging affect Smart Recovery? As I understand it, Smart Recovery uses Stage 1 to slowly creep up to the next set point. But that seems the opposite from Reverse Staging. I'm curious. Does the Reverse Staging not occur during Smart Recovery?

  • gpzbcgpzbc Colorado, USAMember

    To answer my own question...
    After roughly experimenting for a day, it appears that Smart Recovery works as you would expect, even with Reverse Staging on. For example, While away, my set point is 59 degrees. In the afternoon, my home set point is 68. In spite of the fact that I have reverse staging on, Smart Recovery has been running stage 1 heat for the last hour to slowly warm my house back up. This is how I expect Smart Recovery to work. So I guess Reverse Staging takes place only outside of Smart Recovery.

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