how to make Nest thermostat fan delay start

[parkck]

Cable is connected to Y1, G, Rc, W1, C,

Furnace is Day and Night 80U-19 model, old furnace has no control board and the fan control is done by Honeywell Fan & Limit furnace control.

The problem is that when I turn on the heater, I remember that the gas burner first lights up and then the fan turns on after a while, but now the fan always turns on at the same time as the gas.

So, I don't know if it's because of the fan, but sometimes the burner lights up late and the gas doesn't light up quickly, causing a small explosion. Sometimes the furnace door opens wide.

Even when I ask an HVAC expert, they say it's good to set the fan to Delay start, but I can't find the Fan delay start option anywhere in the Google Nest default settings.

What should I do?

Also, HVAC technicians recommend that air conditioner also have a fan running delay.\

[Jeremyg]

Hi @parkck!

Thanks for reaching out to the community. I am sorry that you are having issues with your fan and burner because they are turning on at the same time. But no need to worry; help is here. Before continuing, I need to know a few things:

• What Nest thermostat model do you have? For your reference, you can check out this article on how to tell which Nest thermostat you have.
• When was the thermostat installed?
• What troubleshooting steps have you done before contacting us?

I'll be waiting for your response; any additional details you can provide will be helpful.

Best regards,

Jeremy.

[dzalikowski]

I'm trying to delay my fan until my furnace heats up. My fan comes on right away?

[Jeremyg]

Hi @dzalikowski!

Thank you for reaching out to the community. I understand that you want to delay your fan until the furnace heats up. I'm glad to help you! 

For now, we recommend that you take a look at this article Fan control with a Nest thermostat.

If you have any further questions, please don’t hesitate to reply to this post. I'll be happy to assist you further!

Best regards,
Jeremy.