Nest Thermostat

[GKohler]

I switched from heating to air conditioning today. My nest thermostat worked fine for heating. I got short cycles,  power errors, and wifi connection issues on the display. I have no c wire. In order to make the heat work I had to say there was nothing hooked to the c connection, but I had a jumper from my red wire to the c. I have no c wire available. No combination of wiring made any difference in trying to get the air going. Why would the heat work but not the ac? I hooked up the old thermostat and the air is working fine. Any suggestions? 

[asfeqaxc]

It seems like you're experiencing some difficulties with your Nest thermostat when switching from heating to air conditioning. Here are a few possible reasons why the heat might be working but not the AC, as well as some suggestions to resolve the issue:

1. Power Issues: Air conditioning typically requires more power than heating. It's possible that your current wiring setup does not provide enough power for the AC to function properly. This could explain the short cycles, power errors, and WiFi connection issues you're encountering. One solution to this problem is to install a C wire (common wire) to provide a continuous source of power to the thermostat.

2. Compatibility: It's important to ensure that your thermostat is compatible with both your heating and cooling systems. Some thermostats may work well with heating but encounter compatibility issues with air conditioning. Check the specifications of your Nest thermostat to verify its compatibility with your specific cooling system.

3. Wiring Configuration: Double-check the wiring configuration of your Nest thermostat. Make sure the wires are properly connected and secure. In some cases, incorrect wiring can lead to issues with certain functions, such as cooling. If you had a jumper wire connected from the red wire to the C terminal, ensure that it is properly connected and functioning.

4. Troubleshooting with Nest Support: If you have tried the above suggestions and are still experiencing issues, it may be beneficial to contact Nest support directly. They can provide specialized assistance based on the specific model of your thermostat and any error codes or messages you're receiving.

Additionally, since you mentioned that the air conditioning works fine with your old thermostat, it may be worth considering whether there are any compatibility issues or settings specific to the Nest thermostat that need to be addressed.

Remember, when dealing with HVAC systems and thermostat wiring, it's always a good idea to consult a professional HVAC technician if you're unsure or uncomfortable with making changes yourself. They can help ensure that your thermostat is properly installed and configured for optimal performance.

[asfeqaxc]

It seems like you're experiencing some technical difficulties with your Nest thermostat when switching from heating to air conditioning. It's not uncommon to encounter issues when transitioning between different HVAC systems, especially if there are wiring complications or compatibility concerns. While I can offer some general suggestions, please note that it's always best to consult a professional HVAC technician or reach out to Nest support for specific troubleshooting guidance.

Here are a few potential reasons why your heat might work but the AC doesn't:

1. Wiring compatibility: The wiring configuration required for heating and cooling systems can vary. It's possible that the wiring setup you had for heating is not fully compatible with your air conditioning system. Check the Nest thermostat's compatibility with your specific HVAC system and ensure that the wiring is correct for both heating and cooling.

2. Power supply issues: Air conditioning systems often require more power than heating systems. Without a common wire (C-wire) connection, the Nest thermostat may struggle to receive sufficient power to run the air conditioning effectively. Consider adding a C-wire, which provides a continuous power supply to the thermostat, or explore alternative power options like using a power extender kit (PEK).

3. Equipment or configuration settings: Make sure that your HVAC equipment is functioning properly and that the settings on the Nest thermostat are correctly configured for air conditioning. Check the compressor and fan of your air conditioning unit to ensure they are operational. Additionally, review the Nest thermostat's settings and ensure that it is set to cooling mode.

4. Wi-Fi connectivity: The Wi-Fi connection issues you mentioned could potentially impact the thermostat's ability to control the air conditioning. Ensure that your thermostat is properly connected to your home Wi-Fi network and that the signal strength is strong enough for reliable communication.

Since you mentioned that the air conditioning works fine with the old thermostat, it may be worth double-checking the wiring and compatibility between the Nest thermostat and your HVAC system. If you're unsure about the wiring or encountering difficulties, it's advisable to consult a professional HVAC technician who can assist you in properly installing and configuring your Nest thermostat for optimal performance.

Remember to reach out to Nest support or consult their online resources for specific troubleshooting guidance tailored to your thermostat model and system setup.

[Markjosephp]

Hello GKohler,

Thank you for taking the time to let us know about your inquiry. I'd be happy to take a look at this for you.

Incorrect wiring configuration or setup could cause odd HVAC activation behavior. To be sure, could you please share with us a photo of your old and new thermostats' wiring setup? Also, the Nest Thermostat connectors are built so that only one wire can be inserted into each connector, so you don't need to use jumper wires. Putting more wire into the terminal can damage your system and your thermostat.

I'll look forward to your response.

Regards,
Mark

[GKohler]

I have contacted the Google support. And they have directed me to ship it back for replacement.  They checked it out  remotely and made that decision. Can you be contacted for future needs, if it becomes necessary when I get the replacement?

[Markjosephp]

Hi GKohler,

Sounds great! I'm glad to hear we have found a solution by replacing your thermostat. You can give us a shout if you need more help by creating a new thread, and we would be happy to assist you. Also, I'll be locking this thread within 24 hours, unless I can help you with anything else.

Best,

Mark