2 Zone Nest Install w/New Control Board


  #1  
Old 12-11-16, 05:24 PM
R
Member
Thread Starter
Join Date: Jan 2011
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
2 Zone Nest Install w/New Control Board

Hi all. I just purchased two new Nest thermostats, one for each of the two zones in our home. We have a single furnace (oil) forced air, with the two zones controlled by an existing EWC-ST-2E board. In some reading, I've come to realize that board is not compatible with Nest or other Wi-Fi thermostats. I've purchased a new EWC NCM-300 to swap out. In an attempt yesterday, I was able to get the board swapped out and hooked up the new thermostats, but it didn't behave correctly (my A/C compressor outside actually fired up during "HEAT" mode -- not good).

One other note: I think there's currently a "master/slave" relationship between the zones, as if we actively shut off Zone 1 at the thermostat (not by temperature, but by actually setting it to OFF), Zone 2 will *not* fire up. Other than that, they seem to work well independently.

Anyway, I spent some time pulling together current vs. new in a single attached picture, and am hoping someone can look at it and get me pointed in the right direction. Many thanks in advance for any and all advice!

Name:  Nest_Help_Install.jpg
Views: 3931
Size:  52.1 KB
 
  #2  
Old 12-11-16, 06:20 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,539
Received 38 Votes on 34 Posts
It looks like your new zone control board is a better model than the existing board. That old Slave - Master setup is out of date.

The new thermostats and board will not use the O, B, or O/B terminals.
You do not have a heat pump. ( Even though the old board and zone 1 stat were setup that way)

At your zone 1 stat:
Y1 = yellow
W1 = white
G = green
Rc = red
C = blue

Wire the zone 1 wire connections the exact same way at the zone control board.

Wire the zone 2 stat the same way if you have enough conductors.
Wire zone 2 this way at the zone control board as well.
 

Last edited by Houston204; 12-11-16 at 06:47 PM.
  #3  
Old 12-11-16, 07:01 PM
R
Member
Thread Starter
Join Date: Jan 2011
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Thanks, Houston! Will try this tomorrow.

One question: this configuration will handle cooling as well, correct? We have central A/C.

Also, the previous configuration didn't include a common -- but to confirm, I should add it to the new configuration?
 
  #4  
Old 12-11-16, 07:27 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,539
Received 38 Votes on 34 Posts
One question: this configuration will handle cooling as well, correct? We have central A/C.
Yes, Cooling would be the Y1 terminal.

Also, the previous configuration didn't include a common -- but to confirm, I should add it to the new configuration?
Yes, your new thermostat will function better if common is connected.
 
  #5  
Old 12-11-16, 07:48 PM
R
Member
Thread Starter
Join Date: Jan 2011
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Awesome, thanks so much Houston. Will update tomorrow...
 
  #6  
Old 12-12-16, 05:59 PM
R
Member
Thread Starter
Join Date: Jan 2011
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Houston, just hooked everything up and all is working well. Thanks so much!
 
  #7  
Old 12-12-16, 07:57 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,539
Received 38 Votes on 34 Posts
That is great news. Thanks for posting back with your results.
 
 

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