Nest Power Connector Help

ncatanza05

Need some help on redoing the wiring for my boiler with the addition of the Nest Power Connector.  Following both the Power Connecter directions and the switching relay wiring diagram, I connected the power connector to the R and W wires from the thermostat and connected the three other wires from the power connector into the R, W and 24v COM terminals.  Tested the nest and it is recognizing the power.

my issue is that the thermostat wires were not originally wired into the TT terminals so all of the other wiring needs to be redone.  Below is a photo of what the wiring looked like before the power connector was added and another of after it was connected and the remaining wires I need to find a home for.

EBEBRATT-Ed

get rid of the nest power connector. The only way to make a nest work reliably is wit a seperate transformer and relay see the attached

STEVEusaPA

What’s wrong with the C terminal on the relay. Might need a 1k, 1/2 watt resistor

Zman

STEVEusaPA said:

What’s wrong with the C terminal on the relay. Might need a 1k, 1/2 watt resistor

It looks like he only has 2 conductors to the t-stat.

@ncatanza05 The "5 COM" terminal is not a transformer common.
If you can give us a little more info about your system and how many wires you have going where, we should be able to offer some assistance. What are the white wires in the first picture going to? How many circulators? Is the aquastat the boiler temp? Is the hot water heater an indirect?

Alan (California Radiant) Forbes

http://www.taco-hvac.com/uploads/FileLibrary/102-397.pdf

See note 2.

STEVEusaPA

Zman said:

show previous quotes

STEVEusaPA said:

What’s wrong with the C terminal on the relay. Might need a 1k, 1/2 watt resistor

It looks like he only has 2 conductors to the t-stat.

@ncatanza05 The "5 COM" terminal is not a transformer common.
If you can give us a little more info about your system and how many wires you have going where, we should be able to offer some assistance. What are the white wires in the first picture going to? How many circulators? Is the aquastat the boiler temp? Is the hot water heater an indirect?

What’s this?

Zman

That is the one for the transformer, there is no wire landed on it. I am curious/concerned about the safeties wired into the taco.

HVACNUT

I think it's only a 10 va transformer in there so connecting one thermostat might be ok, but a separate transformer and isolation relay is the only real way to do it IMO. 

lost11

HVACNUT said:

I think it's only a 10 va transformer in there so connecting one thermostat might be ok, but a separate transformer and isolation relay is the only real way to do it IMO. 

That's why I like argo's documentation. It explicitly tells you to use an isolating relay to have proper power for your smart thermostat: https://argocontrols.com/products/switching-relays-accessories/ir882-isolation-relay-3-zones