I didn’t think to hook up the humidifiers when I initially replaced the thermostats in our house with a pair of ecobee 3’s. after the weather turned cold and dry here in chicago I quickly realized my mistake. It’s not that the existing installation didn’t work, it just didn’t work as well as it could, or wasn’t connected to the system the way I would have liked. It wasn’t hard to wire it up, but it wasn’t as easy as replacing the thermostats either, so I thought it might be helpful to document the process.
Reading: How to connect humidifier to ecobee3
The first step is to turn off the hvac system. If you already have a spare pair of wires behind your thermostat, then the first part is easy. I didn’t in either place so I had to pull a 18/2 thermostat wire to both. luckily the trail is a conduit so it was easy. once you have the cable in place, connect the wires to the acc+/acc- terminals on the ecobee mounting plate. after this, the steps were a bit different in the two locations because one of the humidifiers is on and the other has a bypass setting.
The motorized humidifier was the easiest of the two to get working. just turn off the humidistat and then find the wires where it is connected to the fan and water value.
These wires should be easy to locate as they should be the only connection between the humidifier and the humidistat. after locating them, it’s as simple as connecting each wire to one of the 18/2’s that were plugged into the ecobee.
The concept is the same with the bypass model, but since it does not feed into the water valve, it must be handled differently. this confused me initially, but it should have been obvious: no power, no way to open the valve.
There are many ways to handle this, but I went with the easiest one; mainly because I didn’t feel like messing with the existing wiring too much. so i disconnected the red and white wires from the humidistat and connected them directly to the corresponding 18/2 set connected to the acc+/acc- earlier. which in hindsight makes a lot of sense as we are replacing the humidistat with the ecobee.
Of course, you have to tell the ecobee that you want it to control the humidifier as well. after turning the HVAC system back on, head to the ecobee; we must do it on the device itself.
with the humidifier enabled, we just have to turn it on and set the desired humidity level.
The last step is completely optional, but I’m a bit quirky with this sort of thing, so I felt the need to remove the old kit and seal the holes in the ductwork. this is the only potentially dangerous step. so be sure to grab some gloves, along with the duct tape and sheet metal, if you try.