Nest auto switching from Stage 1 to Stage 2 cooling takes way too long, about 2 hrs!

[EdG1]

I have a nest learning thermostat 3rd generation, and it takes 2 hrs before it will change from stage 1 to stage 2 cooling, when the 5 ton ac heat pump cannot get the house to the set temp of 73 deg.

I thought it should switch to stage 2 in like 5-10 min if the room temp does not decrease fast enough.

What is wrong and can I adjust the time it waits to change from stage 1 to 2?

I'm in Orlando FL, and this occurs in the afternoon when it is 95deg outside and attic insulation is not the greatest, one story house.

I can’t find any adjustments in the setup.

I do know that moving the temp setting down about 5 degrees will activate the stage 2 but the nest should also switch to stage 2 based on a slow time to temp response. 2 hrs is just way to long!

[EdG1]

I found the answer in the following manual on pg 14

Google Nest Learning Thermostat 3rd generation Pro Installation and Configuration Guide

https://tssassociatesinc.com/wp-content/uploads/2024/11/Nest-Learning-Thermostat-3rd-Gen-Pro-Install...

Pg 14, Staging:

When there is a call for heating/cooling, the thermostat will not engage a second stage unless the temperature goes in the opposite direction within the first 15 minutes.

If the temperature does not go in the opposite direction from the call to heat/cool, the thermostat will wait 60 minutes for conventional heating to upstage, or 2 hours for cooling.

The second stage of heating or cooling will turn on when you adjust the set point 3.3°F beyond the current temperature, while the third stage will need a change of at least 7°F to activate.

At the start of a heat cycle, auxiliary heat is disabled due to the upstage timer. If the temperature decreases to 0.5C (1F) below the temperature at the start of the heating cycle, then the upstage timer is ignored and aux is enabled until the target temperature is reached.

After this point, a drop of 0.1C is enforced for re- enabling aux during the same HVAC cycle

So, it seems that the time it is not adjustable?

Any other info will still be appreciated.

[moralesvicente]

Hello EdG1, 

Thank you for getting back to me regarding your questions. If the temperature does not go in the opposite direction from the call to heat/cool in the first fifteen minutes, the temperature will be maintained, and the thermostat will stay in stage 1 until two hours have passed.

If you have more questions, please feel free to reach out on this forum. 

Regards, 

Daniel

[moralesvicente]

Hello EdG1, 

Thanks for reaching out to the Google Nest Community Forum. I understand you're experiencing a long delay with the second cooling stage of your Nest Learning Thermostat 3rd gen. Don’t worry, I’m happy to help. 

To gather further details and determine the optimal resolution, I’d appreciate your help in answering the following questions. 

• When did the trouble first occur? 

• Could you attach a picture of your wiring configuration in the thermostat? 

• When did you install your thermostat? 

• Have you performed any troubleshooting steps so far? 

• When was the last maintenance service and cleaning for your HVAC system?

Any additional details you can provide would be helpful. 

Best regards, 

Daniel

[EdG1]

Kit Register output air tempDaniel

If you look at the 1st reply above, the "Nest 3rd generation Pro Installation and Configuration Guide" document says that 2 hours is the actual delay setting by nest.

Please read the pg4 Staging information above.

But, what is not clear in the staging statement is what happens if the room temp increases after the first 15 min period?

Does it ignore the increase and remain in stage 1,

or does it go to stage 2?

The photo clearly shows when the ac goes from stage 1 to stage 2 after 2 hrs. 
It just seems like it is waiting way too long and needs a better algorithm controlling the stages.

The outside temp is about 95deg and the ducts are in a very hot attic. 12N to maybe 6-7pm.