Add LED to Humidifier

Hey guys I just installed a whole house humidifier in my house. It is operated by a 24v DC solenoid that turns on the water supply. I split the common wire with the humidistat (humidity controler inside the house).

I would like to add an LED to the humidistat but have no clue where to start.

More Info:
-24v line from my heat pump-2 wires common and VAC
-I've split the common with 2 wires to the humidity controller (where I would like to put the LED)

It seems a simple a putting a 24v LED in the common line????

Any help appreciated!

Firstly what is the purpose of the LED you are wanting to fit, and secondly, LED's require typically between 2.5 and 4 volts (ish) so you would also need to add a dropper resistor in the circuit. Karl

I want the LED to light up when the circuit is closed (the humidifier is running).

What size resistor would I need to drop 24v to 3v?

Pick an LED and find out the forward voltage (Vf), often specified at 20mA (there are ultra bright LEDs that are 100's of mAs, you don't need one of those). The resistor value can be determined by Rmax = (24v - Vf) / 10mA and Rmin = (24v - Vf) / 20mA. Choose a value between Rmax and Rmin. The closer to Rmin you pick, the brighter the LED will be.

Or to make it easy on you, use a resistor between 1k and 2k.

Thanks for the lesson!
I guess I will have to run another wire down to one side of the resistor??? The common wire is split by the humidistat and is already where I want the LED, but I'm not sure if its as simple as just....

Bring another wire to have both the common and the VAC at the humidistat. Hook the long leg of the LED to the resistor then to the VAC.
Then the common to the other leg of the resistor.

Don't want to fry anything??

Draw a sketch of what you have. I don't quite follow your description of what wires and voltages you have and where you want the led.

What are you referring to as "VAC"? AC line voltage? I would try and use the 24 V DC wire to power the led if that is possible.