Nest heating won't turn on the burner

[Irritated]

Hi 

Nest thermostat won't turn on the burner for heating despite it displaying it as on.

This applies to the schedule and manual switching.

Strangely, the hot water schedule and boost within the app still works without issue.

I've tried resetting device etc

[Saphirewolf]

Same here it is only making my furnace blow cold air right now its 44° in my house 

[Elswann]

It's 6-2.22 - bank on it. They need to fix it. Complain, complain, complain. 

Imagine all the people getting their furnace serviced hoping to find a fix that doesn't exist. 

[ludvigsen-ron]

Did they ever fix this? My house is doing the same now, and I have a newborn!

[Elswann]

The only thing additional I would add based off research is if your flame sensor needs to be cleaned.  Other than that I'm not sure. 

That seemed to help my system. I still think 6-2.22 is a part of it-- but that's a place to start checking too. 

[Saphirewolf]

It turns out my heat exchanger is cracked so I have to replace the whole furnace 

[Elswann]

Ouch.