Nest 'Fan Schedule' Not Working (Doesn't start automatically at time)

[TimothyB]

I have two Nest Learning Thermostats (Display 3.4, Backplate 5.4, Software 6.2-27) for two separate air conditioning units (upstairs and downstairs) connected to Nest App on Android. My home address is set correctly in the Nest App Home Info page (aka for timezone).

Recently I tried to use the "Fan Schedule" feature, however it simply doesn't start automatically. Here's what I'm doing:

1. On both thermostats, I've set "Fan Schedule" for "60 min each hour" (aka continuously) from 1pm to 6pm.
2. When 1pm occurs, the fans do not start automatically as expected.
3. After waiting a while to confirm they're not just a bit 'late', I go into App Settings, uncheck (disable) the "Fan Schedule", and then re-check (enable) it.
4. Fans magically come on (perhaps they finally realize they are in the set time block for the required time?)
5. After the manual intervention above, the the fans Stop at the scheduled stop time correctly.
6. The next day at 1pm - they do not come on again, even though no settings were changed in between.

This has been happening for around a week or so (maybe?) until we noticed the schedule wasn't running.

Please note that at step (4) above, I'm not "Manually Running" the fan. I am disable/reenable the schedule within the schedule block and THEN it works.

PS: Not to confuse things too much, but since noticing, there was at least one day where "Downstairs" did come on a little after 1pm (eg: 1:05pm) while the "Upstairs" never came on at all, but most days, neither come on without jumping in and manually disabling/reenabling the schedule.

[maedacortez]

Hi TimothyB,

Thanks for reaching out! I understand your Nest Learning Thermostat isn't following the schedule you set up in the app. I know how frustrating it can be when your thermostat doesn't follow your instructions.

Here's a troubleshooting step you can try: Reset the schedule on your thermostat and then recreate it in the Nest app. This can help ensure the schedule is synced correctly.

Go to settings > Restart > schedule. 

Let me know if you have more questions.

Regards,

Manuel

[Patrick_Caezza]

@TimothyB 

Do you have two separate HVAC systems or just one with a zone controller? If you have a zone controller have you tried just setting one thermostat fan schedule?

Do you have either of the thermostats set to Off? If you do the fan schedule won't work.

[TimothyB]

Thanks @Patrick_Caezza for the reply - I have two separate HVAC systems. Both are set to "Heat Cool" mode (aka, they're 'on').

Now that the weather has mellowed out, we ended up disabling the fan schedule completely (it's only useful to us during the heatwaves to reduce the heavy all-day AC by instead using fan cycles to bring the cool air up from the basement and circulating the top-floor air that otherwise overheats, but we find the fan too noisy to want this on a permanent schedule, and otherwise let the thermostat "do its thing" on regular days) but for a week or so there it was just super annoying to go into the app in the mornings, untick/retick the schedule, and THEN it would come on.

I guess since we're not scheduling anymore I can close this off and hope an app/unit update resolves it before next time we try (like the Google Home app which mysteriously gets bugs with routines that seem to resolve themselves after some time)

[maedacortez]

Hi TimothyB,

I sent you the steps on how to restart the schedules on your thermostat before. Could you let me know if it worked for you?

I'm waiting for your response.

Regards, 

Manuel