Hi @Gopesh,
We understand how frustrating it can be to repeatedly deal with Error E79 on your Nest thermostat. This issue often indicates a problem with the C-wire, which provides essential power to the thermostat.
To help you resolve this, I’ll need to gather some additional information:
- What Nest thermostat model do you have?
- What's the make and model of your HVAC equipment?
- How many wires are there?
- How are the wires labeled?
- Is the display seated? (Does it properly lock itself into the base?)
- Are all wires firmly seated into the terminals? (with no loose or exposed wires)
- Does the thermostat charge with a USB cable?
While you provide this information, let's work through some potential solutions:
- Check the C-Wire Connection:
- Safely turn off power to your HVAC system.
- Remove the thermostat cover and carefully inspect the C-wire connection at both the thermostat and the HVAC system.
- Ensure a secure and tight connection. Look for any signs of damage or corrosion.
- Inspect Other Wire Connections:
- While you have the thermostat cover off, take a moment to examine all wire connections for any loose or damaged wires.
- Test C-Wire Voltage:
- If you have a multimeter, measure the voltage between the C-wire and another wire. You should see around 24 volts AC. A lack of voltage might indicate an issue with your HVAC system or wiring.
- Evaluate Your HVAC System:
- Sometimes, problems with your HVAC system can cause intermittent power issues leading to the E79 error. Consider contacting an HVAC technician for a checkup.
Safety is paramount. If you're unsure about working with electrical systems, it's always best to consult a professional.
We hope these steps help resolve the issue. If you continue to experience problems, please provide more details about your HVAC system (type, manufacturer) and the wiring configuration.
Best regards,
Josh
