Google Nest Thermostat Error Code E199: How to Fix It

Q: What does error code E199 mean on a Nest thermostat?

Error E199 means your Nest thermostat has detected that the system is not cooling. It's a general warning that cooling isn't working, often due to wiring, power, or HVAC equipment problems.

Q: Can a dirty air filter cause Nest error E199?

Yes, a dirty air filter can restrict airflow, causing the cooling system to malfunction. It's one of the first things to check when you see this error.

Q: How do I reset my Nest thermostat to fix error E199?

Go to Settings > Reset and choose 'Schedule' to reset only the schedule, or 'All Settings' for a full reset. After resetting, you may need to reconfigure the thermostat.

Q: Is error E199 on Nest covered under warranty?

If the thermostat is less than 2 years old, Google may replace it under warranty. Contact Nest support. However, if the issue is with your HVAC system, it's not covered by the thermostat warranty.

Q: Why is my Nest thermostat not cooling but the fan works?

This suggests the fan is running but the compressor isn't. Check the Y wire connection, the circuit breaker for the outdoor unit, and the condenser unit itself. Could be a faulty compressor or low refrigerant.

Abstract

Error code E199 on your Google Nest thermostat means the system is not cooling. This could be due to a wiring issue, a tripped breaker, or a problem with the HVAC equipment itself. Follow these steps to troubleshoot and resolve the issue.