Looking to install a wi-fi enabled thermostat so I can adjust temperature when we’re traveling. My current t-stats are dumb 2 wire jobs. The t-stat either calls for heat or it doesn’t. In looking at ads for the wi-fi version they all require a C wire. Which appears to me to be the power to the T-stat so it maintains a wi-fi connection. But they also seem to require a tie in to the boiler control panel. Has anyone found one with a simple 12VDC transformer like a old fashioned doorbell unit? Don’t really want to screw around with the boiler control panel if I don’t need to.
They generally run on 24VAC, not 12VDC. None of the thermostats are going to care if they’re getting 24VAC from the boiler control panel vs a separate transformer. However, all of the thermostats I’m aware of are using the unswitched side of the 24VAC relay that the thermostat closes to call for heating/cooling to power the thermostat. This means if you hook up a separate transformer you’d be sending the transformer’s 24V into the boiler control panel instead of the panel’s own 24V, and the boiler control panel might care about that.
So if I take a multi-meter and find the 24 volt tap on my zone control panel, I can use that to run a wire to a wi-fi T-stat?
You already have a 24V tap running from the control panel to your thermostat. Your thermostat switches that 24V to the ‘call for heat’ terminal on the control panel. What you need is a common (ground) wire so that you have a power circuit to run the fancy-pants thermostat.
Which is the “C” wire you’re reading about, @Fir_na_tine.
I have a wifi Sensi thermostat requiring no C wire. Works great with the app.
My Nest only has 2 wires. They plug into W1 and Rh. I replaced a dumb thermometer with the Nest. Simple swap.
Love being able to use the app from work and make it warm when I get home.