Double check my wiring

[ChanceD2]

Struggling to get this working. 

 

 

[CoolingWizard]

@ChanceD2 , you nest display does not recognize your C or Rh. For heat pumps Nest recommends you place the 24VAC power in on Rc.  Can you post the picture of your old thermostat so I can verify the wires that were connected? Now, did you turn the power off to your air handler before you started moving wires? If not you might created a short a blew the 3-amp fuse on the control board. 

AC Cooling Wizard 

[ChanceD2]

AC Cooling Wizard.

Thank you so much for responding.   Very much appreciated. 

I'm going to assume that I popped a fuse.  I'm sure I messed up somewhere in the mix of things. 

The 30 A, 250 V fuse (FU3) appears to be soldered to the board.  Please tell me that I don't have to solder to remove it. 

The two 3.15 A, 250 V fuses (FU1 and FU2) both are white and therefore I can't see the wire (new to me).  I read that I need to test with a multimeter.   If I get that far, I think I'll just swap them while I have this thing torn apart.  Is this a bad idea?

Here's my plan, for your consideration

Turn off power

Remove Nest

Replace with factory thermostat (last image)

Replace FU1 and FU2

Pray FU1 is not blown?? (I have no idea what to do)

Put back together

Restore power

See if the A/C and heater work

If I get this far, I'll be done for now. 

~ChanceD2

[CoolingWizard]

@ChanceD2 , the FU3 protects the high voltage supply to the board, and this is for controlling the blower fan and the EEV.  FU2, protects the low voltage side of the control board, and FU1 protects the step-down transformer.  The volt ohm meter will allow you to test the fuse. It is likely FU1 that is blown.  Your original factory thermostat only had 2 wires? So, did you install a new thermostat cable? Please provide me the make and model number of your indoor air handler please. 

AC Cooling Wizard

[ChanceD2]

@CoolingWizard 

Here is the Manual 

The thermostat only  had two wires being used, however the wire in the wall that those two wires came out of had more than 2 wires in it.  I did not pull a new wire. 

I should have asked this last time, can I test the fuse while it's still in the board or do I have to pull it?

ChanceD2

[ChanceD2]

@CoolingWizard 

Here is the setting that I used on the multimeter.   I touched the two probes together to get a tone.  I removed and tested FU1 and it toned.

All of this assuming I'm using this correctly. (it's been a long time)

~ChanceD2

[CoolingWizard]

You have to pull the fuse out to test it properly.  I need that air handler unit model number please.

Since your old thermostat only had 2 wires, it was most likely only controlling the furnace gas valve. 

AC Cooling Wizard

[ChanceD2]

@CoolingWizard 

Make is DAIKIN

Model is RS24RMVJUA

Did I test FU1 correctly? I removed and tested FU1 and it toned with the multimeter set as in the image above.

Thank you for helping.  It's much appreciated!

~ChanceD2

FYI - The house does not have gas lines in it. 

[CoolingWizard]

@ChanceD2 , that is a ductless mini split system and unfortunately they use a two wire proprietary communicating thermostat system. These are not compatible with conventional thermostats, such as the nest or the nest learning thermostat.

AC Cooling Wizard

[ChanceD2]

@CoolingWizard 

I checked the fuse, reinstalled the OEM thermostat and we are in business. 

I don't know how to thank you.   I truly appreciate your time and expertise. 

~ChanceD2

[CoolingWizard]

@ChanceD2 ,
I am sorry you had to go through the long checkout before be we discovered the ductless mini-split system. 

AC Cooling Wizard

[zoeuvre]

Hi folks,

@ChanceD2, thanks for reaching out, and I'm sorry to hear about the situation. I want to check if you managed to see the response above. Please let us know if you still have questions or concerns, as we'll be willing to assist you further. 
 

I appreciate your help, @CoolingWizard. 

Best,

Zoe 

[zoeuvre]

Hi there,

I want to check and see if you are still in need of any help. Please let me know, as I would be happy to assist and answer any questions you may have.

Thanks,

Zoe