If there is no fan option on Nest thermostat this is mainly because there is no wire connected in the G terminal of your thermostat. It must be noted that there are systems that have a dedicated wire for the fan and those that do not have.
If your system doesn’t have a dedicated wire for cooling then you will not see the fan option on your nest as the fan will only come on when there is a call for cooling or heating.
Read also: Fan wont turn off with Nest thermostat
Howeverver, you will also not see the fan option even if your thermostat does have a separate wire for cooling if the G terminal is not connected or.
More Reasons There is No Fan Option On Nest Thermostat
Another possible reason there is no fan option on your nest is that your thermostat does not have the C wire and there were limited wires to be used as a C- wire.
So what generally happens if that is the case is, a technician will use the g-wire as c wire.
As a technician myself, I would get the wire from the g terminal and insert it on the c terminal and do the same on the control block of the air handler.
But this technique will require that you put a jumper between the terminal G of the control block and Y terminal so that the fan is energized and runs whenever there is a call for cooling.
So, if you can’t see the fan option on your thermostat, it’s possible that technique is the cause.
Troubleshooting a Nest thermostat that won’t show fan option
When you notice that there is no cool option on the Nest thermostat, start by pulling off the Nest thermostat from the wall and inspect the wiring behind. Start by checking G-terminal. Is there a wire connected in there?
If there is, Give it a tug and ensure it’s not loose. You can also try stripping the wire at least half an inch to make a proper contact.
If there is a wire already plugged in, ensure that the end is stripped well enough.
Otherwise if there is no wire into the G-terminal, it could be because your nest didn’t have a C wire and G wire was used as a c-wire.
How to run and schedule a fan on nest thermostat
On a Nest thermostat follow these steps:
- Tap your thermostat’s touch bar and select Fan Fan.
- Select how long you’d like your fan to run, then tap to confirm.
3. Choose Start to run the fan or Cancel.
4. Your fan will turn off automatically after the time you’ve selected, but you can turn the fan off early by selecting Stop from the fan menu.