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Nest 3rd gen Learning Thermostat - not controlling humidifier as I would expect.

WisconsinBill
Community Member

 

This is the first winter we have had our Nest 3rd generation Learning thermostat and it is not controlling the all house humidifier connected to the furnace as I would expect.
In December, we had the Nest Humidifier control set to 35%; the humidifier never went on once the whole month.
NOTE: IT worked fine with the previous thermostat and I know it is connected correctly, so the question is about thermostat control.

In January, I set the Humidifier setting to 40%. The humidifier didn't go off for weeks. If the heat wasn't on, it would keep the fan on anyway and the humidifier on also.
We finally got tired of cold air always being blown throughout the house, so I set the Nest humidifier setting back to 35%. The humidifier sensor read 37%.
It still kept going 24 hours a day, humidifier always on. This is not correct; the humidifier should be turned off if the humidify is above the humidity setting.
The little water drops (humidity on) always appear on the Nest display, whether heat is on or not.

Today I tried an experiment, I went into the Nest settings and turned on a "Quiet Time" for later in the day to see if the humidifier would finally turn off during that time.
Surprisingly, the humidifier turned off right away; the little water drops disappeared from the Nest Display. Humidity still 37% and setting is 35%.

It's as if my changing of the humidity setting to 35% didn't have any effect; but then later when I turned on a "Quiet Time", the humidity setting of 35% finally took effect.
Sounds like a software bug in the Nest to me.

Let me know what you think and if there are additional experiments you'd like me to try.

Thanks,
Bill Cole

2 REPLIES 2

zoeuvre
Community Specialist
Community Specialist

Hi WisconsinBill, 

 

Uh-oh! I'm sorry to hear that your thermostat is not controlling your humidifier as expected. Based on the behavior you described, it does sound like there may be an issue with the humidity control function or software of your Nest Thermostat. Here are a few suggestions to further investigate the problem:

 

  1. Double-check the wiring connections between your Nest Thermostat and the humidifier. Ensure that the wiring is correct and securely connected.
  2. Make sure your Nest Thermostat is running the latest firmware version. Outdated software can sometimes result in unexpected behavior or limitations in certain functions. You can check for updates through the Nest app or the thermostat itself by going to Settings > Software,
  3. Try performing a reset on your Nest Thermostat and reconfiguring it from scratch by going to Settings > Reset > All Settings. Afterward, set up your thermostat again, ensuring that you correctly configure the humidifier control settings. This can help rule out any software glitches or configuration issues.

 

Let us know how it goes.

 

Best,

Zoe

Hi Zoe,

Thanks for the reply.  The issue was not that it wasn't physically connected to and controlling the humidifier.  The issue was that it wasn't controlling it as I expected.

Here is what I learned in the last month, perhaps this is per design.

Nest Humidity setting set to 35%.

In the Month of December, the humidifier never went on.  I work in my office near my furnace room, so I can actually hear if the water is running through the humidifier or not.  Nest Humidity was in the upper 30s, so I get why it wasn't running.

In January, we had a cold snap.  Outdoor humidity was very low, Nest humidity dropped below 35%.  Then, the humidifier ran 24 hours a day for a couple weeks.   First of all, with our old thermostat, the humidifier would only be on if the furnace heat was on.  With the Nest, the humidifier is on often even when the furnace heat is not on.  I get that, thermostats have different control logic.   Anyway, when the humidity as shown on the Nest went above 35%, I would have expected the humidifier to go off. But it didn't, it kept running for days.  That is when I submitted this question.   

Ultimately, when the Nest Humidity rose to 38 or 39%, then the humidifier went off and it hasn't been on since.  That was about a month ago.   The Nest Humidity was in the 40s, so I understand why it is not running.   Now the Nest Humidity is 38%. 

So I guess I am trying to understand the control logic as it pertains to humidity.  It's not like it goes on at 34% and stays on until the humidity reads 36%.    No, as I said, it says on for days until the humidity was like 38%, that is what I don't understand.

Thanks for your help,

Bill