Connecting humidifier to Ecobee 3: wiring question

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Old 12-22-18, 12:33 PM
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Connecting humidifier to Ecobee 3: wiring question

Hello,

Looks like I've come to the right place. I have used my humidifier in manual mode only. I just realized that my Ecobee 3 should be able to control this bypass evaporative humidifier. However, I'm a bit confused by the wiring. I've included a couple of labelled photos that might help explain my current set up.

My current humidifier is connected to the furnace only. It is connected via 2 wires to a 24V transformer seen in the photo of the furnace's circuit board. The 24V transformer for the humidifier, in turn, is connected to the circuit board with a black and white wire.

My furnace only has one wire going from the circuit board all the way up to my Ecobee thermostat. This wire actually has 3 conductors (black, red and green). Only the black and red are used. You can also see what I've labelled with the photo of the Ecobee wiring panel. The green conductor is not used (therefore available for other uses? Maybe to help with humidifier to Ecobee wiring?)

For what it's worth, my Ecobee is being powered by a 24V wall plug power adapter that is next to it. They are the two white wires attached to the Ecobee wiring board.

Can you help me with the proper wiring to get the humidifier to work automatically (smartly) with the Ecobee? Hopefully, I don't have to run any additional wires.

Thank you!!!
 
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Old 12-22-18, 01:28 PM
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Welcome to the forums.

Ok.... we see a gas furnace and no A/C system involved.
Connect the green wire at the Ecobee to the ACC+ terminal.

I see the red and black wires in the cable that goes to the thermostat at the furnace.
It's on the R and C terminals.
Where does the cable with red and black go to that is connected to C and G ?
 
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Old 12-22-18, 01:32 PM
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You don't show if there is a humidistat attached to the ductwork. This is usually bypassed if the thermostat is controlling the humidifier.
 
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Old 12-22-18, 03:13 PM
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So at the furnace, only the W, R and G connectors are being used. (The C is not connected to anything)
There are 2 red wires going to the R connector.

One set of the black and red at the furnace goes to the thermostat as you stated.

The other set of black and red seems to go to a big fan at the air intake side of the furnace. (In this new photo, the black and red conductors is the red wire going to the switch on the ceiling here that seems to go to this big fan).
 
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Old 12-22-18, 03:18 PM
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Originally Posted by Astuff View Post
You don't show if there is a humidistat attached to the ductwork. This is usually bypassed if the thermostat is controlling the humidifier.
Yes. There is currently a humidistat in the ductwork.

So in my opening post, I have a photo which shows the furnace and a 24V transformer. There are two wires (black and white) running from the transformer towards the humidistat and humidifier. The black wire goes to the humidifier and the white wire goes to the humidistat.

There is a white wire the goes from the humidistat to the humidifier to complete the circuit.
 
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Old 12-22-18, 03:24 PM
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Originally Posted by PJmax View Post
Welcome to the forums.

Ok.... we see a gas furnace and no A/C system involved.

Yes. No A/C system.
Connect the green wire at the Ecobee to the ACC+ terminal.

I see the red and black wires in the cable that goes to the thermostat at the furnace.
It's on the R and C terminals.

No. there is nothing connected to the C terminal. The red and black wires from the thermostat going to the furnace are on the W and R terminals.

Where does the cable with red and black go to that is connected to C and G ?
See my fuller response above, including another photo.
 

Last edited by bikemd; 12-22-18 at 04:08 PM.
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Old 12-22-18, 05:37 PM
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No need to quote the entire reply. It just clutters up the thread.

That looks like a duct booster fan. If it's connected to C and G at the furnace...... it may never run.
G requires power on it to activate the furnace blower. I would doubt that booster turns the furnace blower on and the furnace CANNOT turn that booster on. Only a thermostat wire connected on to the G terminal could turn the furnace blower and that booster fan on.

Ok...... you'll remove that separate transformer. You will need to connect the green wire to ACC+ at the Ecobee. At the furnace end..... that green wire will go directly to one of the solenoid wires on the humidifier. The other solenoid wire connects to C at the furnace. That's it. There is nothing else in line.
 
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Old 12-22-18, 06:37 PM
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Thank you Pete.

I think I follow what you last said about how the booster fan and the furnace blower works together. I went to the furnace for another look. I'm almost absolutely sure that the black and red wires from the thermostat are going to the W and R on the furnace. And the duct booster fan's red and black wires are going to the R and G connectors at the furnace.

So it really doesn't look like the thermostat wire is connected to the G terminal. The wire at the G terminal is going to the duct booster fan.

So... what do you think? Does your advice about removing the transformer and using the green wire still applies?

Thanks in advance.

Ken
 
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Old 12-22-18, 07:09 PM
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My advice is strictly for the humidifier and that gets wired as I instructed.
I'm not sure if that duct booster is needed but you should look into what it's for.
 
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Old 12-22-18, 11:27 PM
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Hi Pete,

As an aside and sort of trying to further streamline my system. I had an additional thought. As I said in my opening post, I am using a wall plugin adapter that outputs 24V to power my Ecobee (the two white wires at the Ecobee panel). When I first installed the Ecobee, I had an even more limited understanding of my furnace wiring than I do now and only saw two conductors (red and black) going from my furnace to my thermostat. So I went with using a 24V wall power adaptor. But now I am thinking...if I ran a wire from the C terminal of the furnace all the way up to the Ecobee, doesn't that provide 24V power? And then I can eliminate needing the 24V wall plug altogether?

If the above is true. I will try the following:
  • 1st, I will use the unused green wire in the 18/3 bundle to get the humidifier under the control of the Ecobee (ie. following your instructions). Essentially, connecting the humidifier solenoid to the ACC+ connector at the Ecobee and the C terminal of the furnace.
  • If the above achieves my initial objective of getting the humidifier to be smartly controlled by the Ecobee, then my 2nd project will be to eliminate the need for the 24V wall plug powering the Ecobee.
  • To achieve that, an option would be to pull a 18/5 wire to go from my furnace to the Ecobee (to replace the current 18/3 wire). This will allow me the additional conductor to also go from the C-terminal at the furnace to the C terminal of the Ecobee

Does that all sound about right to you?
 
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Old 12-22-18, 11:33 PM
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Sounds like a good plan.

When you run a new cable.... use a 7 or 8 conductor cable.
You'll pickup.... R, W, C, G, and ACC+ plus a few spares.
 
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Old 12-23-18, 12:31 PM
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BTW, just a general "concept" question.

For anyone interested in using a smart thermostat like an Ecobee to control a humidifier, I presume one needs to essentially physically remove the humidifier's own humidistat from the whole circuit/setup. In other words, do not use the humidistat, take it offline and simply reduce the humidifier's wiring down to 2 wires going to the humidifier's solenoid?

Thanks.
 
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Old 12-23-18, 12:45 PM
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Yes.... you will not be using the old humidistat. You can leave it in place.... just bypass it.
 
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Old 12-31-18, 10:10 PM
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Hi Pete,

Just an update. The wiring scheme that you had suggested to get the humidifier under Ecobee control works. I have taken out the transformer that was providing power to the humdifier from the furnace board. I have connected one of the humidifier solenoid wires to the C terminal of the furnace board. The other solenoid wire is connected to my ACC+ terminal of the Ecobee. Thanks!

As I said, I might now try to pull a new 10/6 or 10/8 thermostat wire to go from my Ecobee to the furnace so I can retire the power brick that is providing 24V to power my Ecobee at the present time.

Happy New Year!
 
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Old 12-31-18, 10:28 PM
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Good job. Thanks for the update. Name:  fest4.gif
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Size:  952 Bytes Happy New Year.
 
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