New upgraded thermostat

cortazac

Hello, if anyone can help. I bought my home and I upgraded the first floor with a google nest 4th gen. The basement was working fine but now I don’t have heat downstairs. The basement heat is a old round Honeywell thermostat. I’m not sure what is wrong. What are the buttons in the back for. Does it turn off by itself.

Jamie Hall

All the switches on the back of that thermostat do is control the cycles per hour. From the look of it in the second picture, you have hot water heat, so you want switch 1 on (to the right) and switch 2 off (to the left).

That, however, has nothing to do with the thermostat being on or off. Is that picture of the thermostat in the basement which controls the basement heat? And is that the heat which is not working? Or is it the first floor heat with the new Nest which isn't working?

Need to know that… and also need to know how the two thermostats are connected — it appears that they may be connected to the zone valves directly? Or is there a zone control panel? And how is the new Nest powered?

cortazac

thank you for answering. The thermostat in the picture is from the basement which the heat stop working past few days. The upstairs has the new nest 4 generation which is power by the picture below.

cortazac

The 1st floor new thermostat gen4 is working perfectly. Is the downstairs I’m having no heat and worry the pipe might froze if the temp drops. I’m trying to see if I can figure out, is about to be Christmas too much expenses. Also does the Honeywell round thermostat have a battery I can change? Thank you for helping me. About the connections I’m not I will take a pic when I get home.

109A_5

The zone valve head does not look seated properly. Does that Red wire in mid air belong somewhere ?

HVACNUT

The basement thermostat is a power stealing thermostat. You added an additional power stealing thermostat with the Nest. Now the two robbers fought it out for the bulk of the draw, and unfortunately, the Nest won… for now. If you're handy, both can work. If not, and HVAC pro can get it to work.

SuperTech

That Nest isn't really an upgrade over anything in my opinion. I wouldn't be surprised if you put the original thermostat back on the wall and the problems went away.

The Nest thermostats absolutely need a common C wire to function properly. The Nest thermostats really don't work well with those Taco zone valves. You should connect a separate transformer to the RC and C terminals to power the Nest. Or you can try to install a Fast Stat FSCM00 common maker kit. But the easiest thing to do is go back to the original thermostat. Maybe you can give the Nest to someone for Christmas. Someone like an in law you don't really like or a coworker you don't care for. Let it be their problem.

SteveSan

Please see the wiring diagram below.

If you have any questions, please give Taco Technical Services a call during normal business hours Mon-Fri 8am-5pm EST 401-942-8000 and just ask for Technical Services

EdTheHeaterMan

It is unusual that you are having no problem with the Nest on a Taco 571 valve motor using only 2 wires. But ir it ain't broke, don't fix it.

As far as the basement thermostat that you are having problems with, you could try to find an analog thermostat to replace that "OLD Round" thermostat. that thermostat is actual a newer digital thermostat that is made to look like the OLD ROUND thermostat. i never liked that thermostat.

Try this one:

https://www.supplyhouse.com/Honeywell-Home-T822K1018-Mercury-Free-T822-Heat-Only-Vertical-Thermostat

That will work fine as long as you set the heat anticipator to .9 or 1.0 (See the red arrow)

cortazac

thank you sir for taking your time. There are two taco 571 motor for each thermostat. I believe I’m loosing volts but I will try what you said. Merry Christmas to you and God bless.

cortazac

thanks for everyone who shared their opinion. I resolved my issue by adding an additional transformer and plugging in into an outlet that was in a closet. Everything work perfectly.