hijinks t1_ix8ab17 wrote on November 21, 2022 at 2:52 PM

You need a transistor like doorbells to take in 120v down to 24v

onthelevel3 t1_ix8alqg wrote on November 21, 2022 at 2:55 PM

Transformer*

hijinks t1_ix8eonj wrote on November 21, 2022 at 3:24 PM

thanks.. must have spelled it wrong on my phone and it guessed that

WeaknessNegative392 OP t1_ix8auf6 wrote on November 21, 2022 at 2:56 PM

Is that something I can put in myself? Or do I need to call in a professional. And would it get wired at the thermostat end or on the furnace end and have to run new wires the whole length of the run?

kittenrice t1_ix8vdhw wrote on November 21, 2022 at 5:19 PM

It's a fairly simple thing to do, if you're comfortable working with electricity and have basic tools (like a multimeter).

I would install it at the boiler and use the existing wires, making sure to label them as 24V on the stat end.

Way2Saucy4U t1_ixbws3g wrote on November 22, 2022 at 7:44 AM

Unless I’m misunderstanding, I don’t think this idea will work.

In most programmable thermostats, the “R” terminal on the t-stat is both the source voltage to power the thermostat and also redistributes that same power to each energized output.

Using a transformer to step down the 120V signal voltage will power the 24V thermostat but then the energized outputs will also be 24V back to the furnace. Each thermostat output would individually then need to be transformed back to 120V since the current controls internal to the furnace are looking for a 120V signal.

Also, some thermostats use triacs instead of relays for energizing the outputs. You could potentially damage a thermostat if you put 120V on a 24V rated triac circuit.