Aprilaire Humidifier with Ecobee
This article summarizes the wiring connections to get your whole house humidifer which goes on the HVAC controlled through Ecobee.
First you need to identify and the proper location as per the manufacturer guidance and install the hardware properly.
Then comes the wiring part.
The simplest solution I discovered is that you don’t need any 24v transformers and just connect the two wires on your humidifier to your thermostat controls. In this method I am assuming that you are not trying to control the humidity through humidistat, as it doesn’t make sense doing it if your intention is to connect your humidifier with ecobee.
Some basics, the humidifier and thermostat (ecobee) requires 24v to operate, this voltage is provided through the “C” wire on your thermostat and you will have a corresponding “C” wire on the HVAC control board with the same wires connecting your HVAC control board to the thermostat.
(Step1) Get a 2 wire cable (usually has red and white wires) and connect both these wires to the humidifier cables. The order does not matter here. (below picture shows the connections)
(Step 2) Route this cable from the humidifier into the HVAC housing and connect one end of the cable to the “C” wire terminal on your HVAC control board.
(Step 3) To connect the 2nd cable which is coming from the humidifier wiring, you need to locate the ACC+ cable color coming from your ecobee thermostat wiring. Open your ecobee thermostat and see the color of the wire connected to the ecobee’s ACC+ terminal. This will be the wire (color) you need to locate inside your HVAC housing where the thermostat wire is coming from the thermostat and connect your humidifier’s 2nd wire to the color wire which is coming for ACC+ terminal on thermostat.
(Step 4) Make sure your ecobee thermostat has only ACC+ terminal connected with wire and the ACC- terminal is not connected with any wires, this 2nd step is very important. If you see a wire already connected to ACC-, just remove it and keep it away from other wires and cover it with tape if required.
(Step 5) Once you completed the above steps and verified that ACC+ is the only wire connected and ACC- is not connected at all. Put the Ecobee panel into the terminals and let it boot up.
(Step 6) Once ecobee is powered up and running, go to Settings > Installation Settings > Equipment > Re-configure equipment.
(Step 7) Select the obvious questions like if you have C wire connected, if you have Rc or other things which you should already know.
(Step 8) Then when it asks for adding additional devices, you select humidifier and select that it has only one wire ACC+.
(Step 9) Thats the end of configuration to make your humidifier be controlled by Ecobee without transformer or any complicated wiring or bypass or humidistat etc.
This simplifies the wiring of humidifier and make is super easy.
Alternative tips:
if you didn’t take this route and having issues making your humidifier work with ecobee using transformer, some of the issues I have see which can be fixed easily are:
- if you are using the “HUM” terminal on your HVAC control board to power your transformer, it will only turn on when Heat is turned on your furnace. This is ok but when you may be testing equipment with ecobee, it will not turn on the humidifier since the transformer is not getting power. This option will still work when you are actually using heat and humidifier will turn on.
