Nest Wiring to Aquastat

dooododoo

Hopefully this is simple to answer. I tried searching google and this forum, but I didn't get any results.

I have a Repco boiler with a Honeywell Aquastat.



It is a rental and I want to install a Nest E thermostat so I don't have to drive down each time I get a heating complaint.

According to the Honeywell manual, the Tv and T terminals go to the thermostat. It doesn't say necessarily which goes to R and W. Does it matter to Nest E which goes to which?



If I want to add a common wire, do I tap into the W or Z terminals on the Aquastat? I found one webpage alluding to that, but the information on that page didn't seem credible. If someone could confirm, or answer this question, that'll be great.

Thank you.

HVACNUT

W-Z is your common.
TV is your 24v so switch the red and white wires so they correspond to R and W at the thermostat.
Do you plan on running a new 3 conductor thermostat wire because I only see 2 wires?

dooododoo

> @HVACNUT said:
> W-Z is your common.
> TV is your 24v so switch the red and white wires so they correspond to R and W at the thermostat.
> Do you plan on running a new 3 conductor thermostat wire because I only see 2 wires?


Thank you for your help.

Yes, I’m going to replace the 2 conductor with a 3 conductor wire. Then it’s a matter of connecting it like this, correct?

Aquastat - wire - Nest
Tv - red wire - R
T - white wire - W
W or Z - blue wire - C

HVACNUT

That's all there is to it. Then the Nest will guide you through the promps.
Nests also make nice hockey pucks.