Nest wiring to humidifier

Reply

  #1  
Old 04-18-14, 02:50 PM
F
Member
Thread Starter
Join Date: Mar 2011
Location: USA
Posts: 44
Received 0 Votes on 0 Posts
Nest wiring to humidifier

Hi,

I have an Aprilaire 550 and I want to wire my Nest 1st Gen to it. My Nest is currently operating my Rheem furnace without any issues. Can someone help me with how to wire it? When does a relay come into play? I have attached a diagram of the current setup.

Thanks,

Doug
 
Attached Files
File Type: doc
Nest Wiring.doc (48.0 KB, 187 views)
Sponsored Links
  #2  
Old 04-18-14, 05:42 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
I see your diagram.
I'm assuming that transformer is wired to the HUM terminals on your furnace control board... correct ?

Name:  11.JPG
Views: 1130
Size:  21.4 KB

It would be helpful to know the make and model of your furnace.
You will also need one additional wire between the thermostat and the humidifier/furnace.
 
  #3  
Old 04-19-14, 07:54 PM
F
Member
Thread Starter
Join Date: Mar 2011
Location: USA
Posts: 44
Received 0 Votes on 0 Posts
I just checked and one wire is connected to neutral and the other I believe is going to ground (can't really tell as it's connected to a plug). This is a Rheem Classic Super Quiet 80. Nothing is hooked up to my HUM terminal.

Thanks,

Doug
 
  #4  
Old 04-20-14, 10:30 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
Ok... so it's plugged into an "always live" receptacle.

I would use a basic 24vac normally open relay to do what you want. It would use that transformer and the Nest would activate the transformer.

Does that nest have the multi purpose * output connection like the version two does ?
Did you locate a spare wire from t'stat to furnace for the * connection ?
 
  #5  
Old 04-20-14, 07:40 PM
F
Member
Thread Starter
Join Date: Mar 2011
Location: USA
Posts: 44
Received 0 Votes on 0 Posts
The 1st Gen only has a Aux/W2 connection. I believe only the Nest 2nd Gen can be hooked up to a humidifier. I have a 2nd Gen on the first floor I can swap out. Can you sketch a diagram for me so I can get a better understanding on how to wire this?
 
  #6  
Old 04-20-14, 08:29 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
Your diagram...... redrawn.

Name:  11.JPG
Views: 431
Size:  25.2 KB
 
  #7  
Old 04-21-14, 07:18 AM
F
Member
Thread Starter
Join Date: Mar 2011
Location: USA
Posts: 44
Received 0 Votes on 0 Posts
Thanks! I will give it a shot. Can you point me in the direction on which relay to purchase?
 
  #8  
Old 10-03-15, 07:16 PM
F
Member
Thread Starter
Join Date: Mar 2011
Location: USA
Posts: 44
Received 0 Votes on 0 Posts
I'm revisiting this project and was wondering if I can just connect connect it this way without using a relay. Will the nest provide enough voltage to activate the solenoid on the humidifier?

Nest * connection --> 1st hum solenoid wire
C terminal on furnace ---> 2nd hum solenoid wire

Thanks.
 
  #9  
Old 10-03-15, 07:37 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,069
Received 1,109 Votes on 1,029 Posts
I had to go back and re-read the thread. Been a while since you've been here.

Yes.... the nest has enough oomph to run the humidifier. It's more about the size of the transformer that is running the furnace. Worst case...... you'll need to upgrade to a 40va transformer if that one fails.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: