topic Re: Nest thermostat doesnt activate the heat in Nest Thermostats

Nest thermostat doesnt activate the heat

Dech — Mon, 25 Oct 2021 18:53:52 GMT

I recently installed the nest thermostat and all the wireds are connected properly but it doesn't activate the heat when I change the temperature. I also installed the power connector for the c wire

Wiring shows connected to w(p) -r

Voltage shows 31.xx

Power connector detected.

The power connector is connected as per the wiring behind the thermostat

Re: Nest thermostat doesnt activate the heat

saltyegg — Sun, 21 Nov 2021 07:19:41 GMT

I’m having the same issue

Re: Nest thermostat doesnt activate the heat

Jake — Thu, 09 Dec 2021 20:58:35 GMT

Hey all,

Sorry for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Best regards,
Jake

Re: Nest thermostat doesnt activate the heat

NatD — Tue, 14 Dec 2021 12:10:51 GMT

Nest 3rd gen, added C-wire. Everything looks right on the display, but no heat. Shorting W to Rh actives heat. 3-zone system using Taco 571 valves. Everything works with a Honeywell TH6110D. Another zone works just fine with a Nest thermostat E on two wires. I tried using a relay (RIBU1C) between W and C but the contact between Rh and the zone valve never closes. Software issue suspected?

Re: Nest thermostat doesnt activate the heat

jammy1954 — Tue, 26 Jul 2022 14:30:34 GMT

Hi @NatD : Did you ever get the Nest to work with the Taco 571 zone valve? I am about to try installing a Nest 2020 thermostat (mirror face) on a heat-only zone that is controlled by a 571. I have R, C & W wires.

On another forum, a user claimed that an isolation relay would be required between the Next and the 571 because the 571 will intermittently open the R-W circuit to prevent the heating element from overheating the wax in its first stage.
I'm curious if you found a different solution.