11-09-2022 08:51 AM
I've got a gas furnace with a mercury style thermostat. 12v ac transformer. no C wire.
11-09-2022 10:24 AM
I've read the manual, and I saw 24v there, if it goes lower than 24v, it will not be enough.
11-09-2022 12:33 PM - edited 11-09-2022 12:41 PM
The only Nest thermostat that works with 12VAC is the one that comes with the Nest Heat Link used in Europe. Now, if you are in North America, and have a gas valve directly wired to a thermostat, that connection is 200 to 300 milliamps of DC Current used to operate the gas valve. The DC current comes to the thermostat on the R, and when heat is needed, it is connected by the thermostat to the W and sent back to the gas valve. This 300 milliamps will cause the gas valve to open.
Ken, The AC Cooling Wizard
01-13-2023 08:33 AM
Thank you everyone for your replies.
I ended up getting a new charger off Amazon that wired directly to the thermostat.
Once connected the thermostat connected to the heat link no problem.
Thanks again everyone!