Honeywell T6 to Ecobee Enhanced adding humidifier control

SHStormont

I have an AprilAire 400 humidifer connected to a American Standard/Trane furnace controlled by a Honeywell T6 Pro. I'm going to switch out the T6 with an Ecobee Enhanced for many reasons (including being able to change the humidity level which the T6 can't do). Currently the humidifer is wired directly to the furnace (red and white wires pictured) with no standalone humidistat. The current wiring of the T6 is also pictured. I have humidistat cable but would like to avoid running it between the humidifier and Ecobee if possible.. For the Ecobee Enhanced to work in 1 wire mode, is it as simple as moving the C cable to the ACC+ on the Ecobee and then setting it to one wire mode?

Big Ed_4

You would need another wire for the Ecobee to be the humidistat for the system .. Surprised there is not one on the system , normally installed upstream of the humidifier in the return …

SHStormont

No humidistat at all.

Where would that new wire run?

SHStormont

Did some more digging on this:

Furnace board:

Y1 = Yellow to Ecobee (Y1) and humidifier red (which connects to the white going into the humidifier)

C = Blue to Ecobee ( C ) and humidifier white (connects to a yellow cable going to the solenoid on the humidifier)

R = Red to Ecobee red

G = Green to Ecobee green

W1 = White to Ecobee W1 and jumper on furnace board to W2

So I think that means removing the red from Y1 on the furnace board, then connect the white from the red/white wire nut at humidifier (humidifier cable red will be disconnected at both ends then) to a new cable connected to PEK+ on the Ecobee?

HVACNUT

The 400 is an evaporative bypass humidifier. Is the Ecobee able to run the fan on a call for humidity?

Install the model 60 humidistat in the return, upstream from the 400.

Download the 400 manual if you don't have. I don't recommend fan activation on a bypass unless it's fed with hot water. Even then it's iffy. Have you seen the Aprilaire 800?