Setting up a delay for fan

[CJ3001]

Can I use Nest to delay fan shut off after ac or heat mode cycles?  If so, how?  I could set up my honeywell thermos to delay fan shut off for up to several minutes to use energy left over in coils and to dry out coils when ac was running.

[MelbaDT]

Hey CJ3001, 

Thanks for reaching out. 

I'm afraid the Nest thermostat doesn't have the option to delay the fan shut off after you've turned off heat or cool mode. However, if your forced air system that has a separate fan wire in your Nest thermostat’s G connector, you can run the system fan when it’s not heating or cooling. If not, your fan will only run automatically when your system is heating or cooling. 

If you have a system with a dedicated fan wire, you can manually turn on the fan with the app or your thermostat, or set a fan schedule. For example, you can set the fan to run all night and automatically turn off in the morning. Check this link for more information: https://bit.ly/3sjMcCP

Best, 

Melba

[MelbaDT]

Hey there, 

Checking back in should you have further questions here. Let us know by replying to this thread. 

Best, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.

Best, 

Melba

[Stevenly95]

Unfortunately, from a commercial hvac service technician point of view, the lack there of a fan cycle delay in a gas fired unit can cause major issues and many callbacks (resulting in more paid by the customer for each call back). Gas fired units, when running in heat, heat up your heat exchanger to 130+ degrees and even hotter with stagnant air. The fan needs to run at minimum 30 seconds after a call for heat is satisfied. If not, the heat exchanger will heat up and cause the high limit switch to trip. Locking out the unit from hearing. Since the fan only comes on in a call for heating, it is impossible for the heat exchanger to cool off. Basically locking out the unit from working until the heat exchanger cools off which is virtually impossible without the fan running unless a long period of time has elapsed for the heat to disapait on its own. There needs to be a fan cycle delay in a call for heat on these stats.

[Jenelyn_O]

Hi Stevenly95,

Thanks for reaching out — I'm sorry for the delay. I just want to follow up if you're still encountering the issue. Please let me know as I'll be willing to assist you from here. 

Best,

Jenelyn

[Jenelyn_O]

Hi there,

Checking in if you're still encountering the issue. Please let me know as I'll be willing to assist you. 

Thanks,

Jenelyn

[Jenelyn_O]

Hello Stevenly95, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within 24 hours. If you need assistance or want to discuss topics, feel free to start a new thread.

Regards,

Jenelyn