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Ecobee3: Switching from compressor to aux sounds rough

Hello everyone! I'm loving my Ecobee3 except for one thing I can't quite figure out. I believe that the thermostat is crossing a time or temperature threshold that forces the system from using the heat pump to using auxiliary heat to heat my home. When this occurs, there is what I would call a banging sound and it sounds very rough on the system. Can someone take a peek at my thermostat settings to see if anything stands out?

Thermostat Model: ecobee3
Firmware Version:

Auto Heat/Cool: Enabled
Heat/Cool Min Delta: 2 degrees F
Compressor Min Cycle Off Time: 300 seconds
Compressor Min Outdoor Temperature: 10 degrees F
AC Overcool Max: Disabled
Aux Heat Max Outdoor Temperature: 50 degrees F
Heat Differential Temperature: 0.5 degrees F
Heat Dissipation Time: Automatic
Aux Min On Time: 5 min (default)
Cool Differential Temperature: 0.5 degrees F
Cool Dissipation Time: Automatic
Compressor Min On Time: 5 min (default)
Compressor to Aux Temperature Delta: 6 degrees F
Compressor to Aux Runtime: Auto
Aux Reverse Staging: Off
Temperature Correction: +0 degrees F
Hummidty Correction: +0%
Thermal Protect: Disabled
Installer Code: Disabled


  • kevinmcckevinmcc Macomb, ILMember
    edited November 26

    @beamer7296 said:

    Heat Differential Temperature: 0.5 degrees F - I would increase to 1 F, otherwise you will get a lot of short cycling on and off which is not efficient.

    Aux Heat Max Outdoor Temperature: 50 degrees F - If you have a newer system decrease the Max Outdoor Temp something lower to keep AUX from running when not needed. I have mine set to 35 F.

    Compressor to Aux Runtime: Auto - I can not remember what I set to get this disabled, for me this is not set and greyed out.

    Compressor Min Outdoor Temp: Not Listed - My heat pump is good to -10 F, so I have this set to disabled because my aftermarket defrost board has -10 F cutoff. Depending on your system and location you may want to adjust this. Ecobee even after years of complaining still has not addressed modern systems can operate below 0 F...

    Is your coil upstream to the AUX? Meaning the return air hits the coil then the AUX? If that is the case, turn on Aux Heat Simultaneous Operation to let the heat pump preheat the air when AUX runs.

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