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HVAC Forums => HVAC Help => Topic started by: filiberto on January 30, 2021, 07:39:03 PM

Title: Nest RH POWER ISSSUE - NEED TO ADD 5th WIRE
Post by: filiberto on January 30, 2021, 07:39:03 PM
Hey everyone,

I moved into my current place in March of last year, and a friend installed my Nest thermostat. Everything was working fine until December/January when we had really cold weather in Ontario. My furnace was cycling on and then I'd get a error saying No Power on RH on my nest. It would clear the issue and then start heating and the same error was come up. I was reading and I need to add a 5th wire to solve the issue.

I ordered a "Venstar ACC0410 Add-A-Wire Kit" and I'm not sure exactly how to install it on the furnace side. I watched the video on the website (https://youtu.be/FjkPh1_I40A), but the only problem I'm having is how to connect it to the furnace as one of the wires from the HRV and NEST are joined.

Attached is the crude drawing of how my cabling is currently hooked up. The bottom left is how my original dumb thermostat was set up, the bottom right is how the video changed the wiring around to add the directional diode.

What should my furnace side wiring look like?