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HOW TO CONNECT 3 POWER CONNECTORS WITH 3 NEST THERMOSTATS TO TACO SR-504 EXP RELAY BOX

abellomo1992
Community Member

I am trying to install 3 Nest Thermostats (2020), one on each floor of my home, and I have 3 Power Connectors. I have a Weil-McLain oil boiler with a separate water heater. This is a heating-only system. Each of my thermostats have 4 wires (red, white, blue & green). According to the directions, it shows that I only connect the W & R wires to the thermostat in each of my rooms and ignore the blue & green wires.

  • Does each power connector get installed/connected at the relay box (I have a Taco Relay Box 007, SR-504 EXP).  This also has a Junction box. I’m attaching photos of the Relay Box and junction box. 
  • On the left side of the relay box is the COM red wire and the 24 VAC cream/tan wire.  If I connect the COM red wire to 1 of the Power Connectors. How will I then connect the other 2 Power connectors to the COM red wire since it’s already attached to the 1st power connector?   
  • Do I just connect the thermostats to the W & R and ignore the blue & green wires?
  • My zone 3 has the green & blue wires connected on the relay box and the same color wires were connected at my old thermostat…..which color would I hook up to represent W & R on the power connector?IMG_3508.jpgIMG_3507.jpgIMG_3498.jpg
1 REPLY 1

zoeuvre
Community Specialist
Community Specialist

Hi abellomo1992, 

 

Thanks for posting here in the Community forum. Your zone system has terminals that are not the same as what the Nest Thermostat base has. To prevent damage and avoid confusion, I recommend you contact a Nest Pro technician to professionally install your Nest Power Connectors for you.

 

Let us know if you have any other questions.

 

Best,

Zoe