Can I connect to full thermostats to the same AC unit?

Old 08-18-11, 01:20 PM
Thread Starter
Join Date: Aug 2011
Location: usa
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Can I connect two full thermostats to the same AC unit?

My house was built in the 1990's.

The way it is set up in regards to the upstairs and downstairs, there is one unit outside, with two separate thermostats. (The basement has its own completely separate thermostat and unit)

The upstairs one will only work when the downstairs one is set to either cool or heat. If it is set to off, then the upstairs one wont work at all.

The upstairs thermostat has a W, Y, and two R's bridged together.(picture here)

The upstairs thermostat is about 10 feet away from the circuit control board (picture here).

Is there a way for me to replace the thermostat and connect it differently, so that the upstairs will work independent of the downstairs (that even if downstairs is on off, the upstairs one will work)? I would want to put the Trane TZEMT400BB3
upstairs (I believe it requires a "C" wire)

Thank You
Old 08-18-11, 04:54 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 6,532
Received 95 Upvotes on 88 Posts
Yes, but you will probably need a different zone control board.
What type of heat do you have?
Do you have motorized zone dampers?

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