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Wiring nest to a TACO SR-503 zone board

kanto501
Community Member

I'm trying to install a nest 3 to zone 1 of the Taco board as a replacement for a failed Honeywell programmable thermostat. The old thermostat had just a red and white wire connected with the white to the white terminal and the red to the Rh and a jumper from Rh to Rc.

Now these 2 wired to to the zone 1 connections on the taco. I have a blue wire I can use for the C wire but I'm not sure where to put it on the taco board. I do see a 2 terminal 24VDC block with one terminal listed as com. Is that where it should be hooked up to or am I way off. I'll attach a pix of the taco.

Taco SR-503Taco SR-503

1 ACCEPTED SOLUTION

kanto501
Community Member

I solved this by finding another post titled something like C wire hookup to taco box. In that thread it says you should hook your C wire from the C terminal of the nest(Blue wire normally) to the COM connection in the taco box. This is found in the upper left of the board. You will find 2 terminal connections. The top says 24VAC and the bottom says COM. Just hook your blue wire to the COM terminal and now all is good.

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5 REPLIES 5

kanto501
Community Member

I solved this by finding another post titled something like C wire hookup to taco box. In that thread it says you should hook your C wire from the C terminal of the nest(Blue wire normally) to the COM connection in the taco box. This is found in the upper left of the board. You will find 2 terminal connections. The top says 24VAC and the bottom says COM. Just hook your blue wire to the COM terminal and now all is good.

MelbaDT
Community Specialist
Community Specialist

Hey kanto501, 

 

Thanks for posting and for keeping us in the loop on what you've done to have your concern rectified — give yourself a pat on the back for a job well done!

 

Feel free to let us know if you have more questions in mind. 

 

Cheers, 

Melba

aatienza
Community Specialist
Community Specialist

Hey kanto501,

 

Chiming in to check if you have additional questions or concerns as we will be locking this thread within 24 hours. 

 

Let us know so we can assist you right away.


Thanks,

Archie

JayToomey
Community Member

Does anyone know if you can hook multiple C connectors to the one com location?

Markjosephp
Community Specialist
Community Specialist

Hello JayToomey,

 

Thanks for reaching out. Let me take a closer look your HVAC systems configuration.

 

A few questions: do you have multiple Nest Thermostats connected to the same HVAC system? Also, are you having any power issues? Here's a link that might help.

 

I'll look forward for your response.

 

Thanks,

Mark