R wire is buzzing after installing into Rh

[Felixyu1988]

There's a faint buzzing sound after I connect the R wire to Rh for the learning thermostat. Like others suggested, I tried to clean the wire and the connector but the faint buzzing is still around after. Any other suggestions? Thanks

[Markjosephp]

Hello Felixyu1988,

Thanks for letting us know about the buzzing sound you're hearing on your Nest Thermostat after the installation. I'd be happy to take a look at this for you.

This is most likely a power-related issue that is causing this. To better check this, please share with us a picture of your old thermostat and the Nest Thermostat's wiring setup. Also, gather the power readouts in the Technical Info settings on your actual thermostat's settings and check for any wiring reports in the Equipment settings.

I'll look forward to your response.

Regards,
Mark

[Felixyu1988]

old thermostatCurrent setupPrevious setupHi Markjosephp,

Thanks for your response. Yes I agree that this is likely a power-related issue as well. I have uploaded the pictures here. I have yet to do the power readouts out of the nest thermostat but will provide that info here once I get to it. 

Thanks,

Felix

[zoeuvre]

Hi folks,

@Felixyu1988, thanks for the information. I see that you connected the thermostat wires to the Nest Learning Thermostat base correctly. In that case, gather the power readings of your thermostat by going to Settings > Technical Info > Power (Battery, VOC, VIN, and lIN) so we can check if power-sharing causes this.

We'll keep this thread open and wait for your update. 

Best,

Zoe 

[Felixyu1988]

Hi Zoe,

Thanks for your reply. I have attached an image of the power readings from the Nest Thermostat here. 

Regards,

Felix

[zoeuvre]

Hi Felix,

It's me again, and I'm sorry for the delayed response. Please follow these steps: 

1. Make sure the RH wire is completely inserted to its terminal. 

• For safety reasons, turn off the HVAC system's power at the fuse box or system switch.

1. Remove the thermostat's display.
2. Check the RH wire connector and make sure that the wire is fully inserted.
3. If necessary, reinsert the wire so that the connector buttons stay fully pressed down. The thermostat may not detect the wires if the connector buttons aren't pressed down.

2. Check if the HVAC system needs maintenance. 

• To diagnose possible system maintenance issues, install your old thermostat and test your system. This method is useful to determine if there’s a maintenance problem with the system or if the system doesn't provide enough power to the thermostat.
• To reinstall the previous thermostat, follow these steps:

1. For safety reasons, turn off the HVAC system's power at the fuse box or system switch.
2. Uninstall the current thermostat.
3. Connect the previous thermostat.

3. If there’s a wire in the C terminal. 

• Sometimes the wire in the Nest thermostat’s C terminal isn’t properly connected to the system or the thermostat.
• Do the following steps:

1. Double-check that all wires are in the correct terminals. Use the thermostat wiring diagram and the picture of the previous thermostat’s wire setup as a guide.
2. If the thermostat doesn't turn on, refer to the article Troubleshoot when your thermostat won’t turn on.
3. If there's an error code or wiring report on the thermostat, refer to the article Troubleshoot Nest thermostat help codes.

Let us know how it goes. 

Thanks,

Zoe 

[Felixyu1988]

Hi Zoe, 

Thanks for the recommendations. I've tried Option 1 and 3 but unfortunately the buzzing sound still exists. I can't try Option 2 as I don't have my previous thermostat anymore but I do remember that the honeywell thermostat did not have the buzzing sound. 

I am wondering if cleaning the contact point of the Rh wire and the base plate will help?

Thanks,

Felix

[Markjosephp]

Hi there,

I appreciate the help, Zoe.

@Felixyu1988, thanks for trying the suggested steps above. In addition to what you already did, let’s also try to remove the C wire and check if the issue persists. If it does, we might need to check the wires with a voltmeter. For safety reasons, turn off the HVAC system's power at the fuse box or system switch.

1. Remove the display of the Nest thermostat and unplug the C wire and the RH wire.
2. Set the voltmeter to AC current.
3. Touch the C wire with the red test probes (positive wire) and touch the RH wire with the black probes (negative wire).
4. You should get a voltage reading, and it should be within 24 volts.

If you’re not getting any voltage readings, we recommend that you contact our Nest Pro technician by going on their website, OnTech, or contact a local HVAC technician to look into your common wire. I hope this will help, but if you encounter any problems doing this or the issue persists, please let us know.

Regards,

Mark