Wondering Why My Thermostat Turns on my Heat Pump Fan for No apparent Reason

[KMJU]

I installed a Nest Learning Thermostat last Spring but had it turned off for most of the summer because of relatively mild weather.  Now that the cooler weather is setting in, I've turned the unit back on and set the temp to 70-degrees.  All is fine except I'm noticing that during the day, when the house temp rises above 70 degrees, the fan (though not the compressor) turns itself on for no apparent reason.  

Wondering if this relates to the Airwave function.  The fan, even with the compressor off, still draws electrical current so not seeing any benefit.  Hoping some Nest Learning user out there can make sense of this.

Thanks,

--Kevin  

[Pdshedges]

Some HVAC systems are used for air recirculation to remove excess moisture to prevent mold and other damage. Systems like the Coleman evcon blend air in manufactured homes have a separate dan in the attic that run 4 hours on then 4 hours off as long as the thermostat is set to heat, cool, or fan

[KMJU]

I really do appreciate your taking the time and effort to respond.  But the situation I'm inquiring about involves a water-fed horizontal heat pump, rather than an attic fan.  I installed a Nest Learning Thermostat (NLT) several months ago but didn't have much need to have it switched on because of a relatively mild summer.  But since the onset of the heating season, I'm noticing that the fan mode turns on even though the ambient temp is several degrees above the 70 degrees the NLT heat mode is set for.  

Just not understanding why the fan mode would switch on and draw electrical current when the ambient temp (~75) is above the set temp level (70).  This never happened when I was using a manual thermostat that the NLT replaced.   Just rrying to figure out what's going on.

[zoeuvre]

Hi folks,

Thanks for chiming in, @Pdshedges. 

@KMJU, yikes! I'm sorry for the late response. Let's see what's going on. 

The Nest Learning Thermostat's Airwave function is a feature that saves energy by using the fan to circulate cool air after the compressor has turned off. When the thermostat detects the compressor's set temperature, it activates the fan to optimize energy efficiency. The Airwave function maximizes the use of cooled air and reduces compressor cycles, resulting in a more comfortable indoor environment. Keep in mind that the names and locations of these settings may vary slightly depending on the version of the Nest app or firmware you're using. To adjust the Airwave feature, check the thermostat's settings. To access the Airwave settings, follow these steps:

1. Open the Nest app.
2. Tap on the Settings icon (gear-shaped) in the top right corner.
3. Select your Nest Learning Thermostat from the list of devices.
4. Scroll down and select "Cool to Dry" or "Airwave" from the list of options.
5. Adjust the settings or disable the Airwave feature according to your preferences.

Let us know if you have any other questions.

Best,

Zoe

[KMJU]

It turns out that Airwave is not the culprit.  Apparently, the Fan Schedule was pre-set to run at a certain time each day.  Must have been a default setting.  Turned the function off.  Problem fixed.  This post can now be cleared.

Thanx,

--Kevin

[zoeuvre]

Hi KMJU, 

Great! I'm glad that everything has been sorted out. If you have questions or concerns in the future, feel free to start a new thread, and we'll be happy to help.
 

All the best,

Zoe