Emerson Sensi Thermostat

[CThome]

I have a 2 Zone, Master/Slave configuration on my Lennox furnace. I recently replaced the Emerson 1F97-12377 Programmable Thermostat with an Emerson Sensi Thermostat. The new thermostat works on Zone 1, but the Zone 2 2nd floor thermostat is no longer able to open the dampers to bring heat to the 2nd Floor. The Sensi Thermostat is not able to control the 2nd thermostat. Is it possble to make the 2nd thermostat totally independent of the Sensi Thermostat (i.e. eliminate the Master/Slave configuration0?

[Paul Z.]

You will have to replace the ST board with a NCM-300.

[Paul Z.]

Your new thermostat for zone one needs to have must have a "O" and "B" terminals not O/B Honeywell 4110 series will wor. Zone 2 any one you want. You might want to change board to an NCM-300 that will handle any type.

[y2kflhr]

Just curious what you wound up doing? I am in the same boat, I purchased a sensi and my upstairs isn't working, tech support said I need to add a Single Pull, double throw switch. Would I be having the same issues with a Nest or a Lyric?
thanks

[Mooring10]

I downloaded the Sensi app and it told me my system was compatible based on the wires on my Master thermostat; when I check on the website wirepicker compatibility, it says my system is not compatible! It appears their algorithms are different and both assume I have a heat pump based on the O and B wires--I do not.

I have a 2-Zone Gas/AC system with two existing White-Rodgers 7904 5/2 Programmable Thermostats. The zone control is a DuroZone SMZ-SW. There are three DuroZone dampers (2 on one zone). The O and B terminals are connected on the Master Thermostat and the zone controller board. According to the DuroZone sheet, the O and B look like they control the zone dampers.

The Sensi app said to match (old-new) RH-RH, B-C, O-O/B, W-W/E, Y-Y and G-G.

I installed it according to the instructions. I could not get the Wifi to connect so I decided to at least set it manually for overnight. When I turned the heat up very cold air started to blow from registers--I think it may have turned my AC on when it was 10 degrees outside. It ran for maybe 10 minutes before I knew something was wrong and turned if off. Have I ruined my AC?

I just got off the phone with Emerson. I told them their app says it is compatible, and their website says it isn't. The tech told me Sensi does work with zone systems, but it is NOT compatible with mine. He said I could ignore the B and O wires and use it without the zones--not sure how well that would really work.

I am stumped. I'm looking for an internet solution to controlling my HVAC, I don't have a C wire going to either of the existing thermostats. Is there anything available where I don't have to install a new zone board and dampers? I had a Honeywell RedLink proposal but it was nearly $2,000 for the equipment and install. Some are telling me my DuroZone dampers will not work with other zone boards. They are motorized, not spring.

What I am trying to accomplish is to turndown the HAVC while we are away on weekends and then turn it back on when I know we are coming back (so we don't come into a 55 degree house and wife will treat me better). A work around I am considering is to buy a 7-day programmable and set the heat to 55 on Friday afternoon and back to 68 on Sunday afternoon. The Emerson 1F95-1277 seems to fit this scenario and it has O and B terminals. Will the O and B terminals on the new Emerson work the same as my older 7904?

Thanks for any and all advice--This is probably a DIY job I shouldn't have started.

[Paul Z.]

Zone one terminal block need to have the "O" "B" wired to the thermostat. You stat can not wire that way.

[Mooring10]

Zone one terminal block need to have the "O" "B" wired to the thermostat. You stat can not wire that way.

Thanks for your reply and this forum.

I now understand that the Sensi stat will not work with my current system.

Any comments on my questions in red above?

If I switched out the DuroZone board for the NCM300--could I then use the Sensi? I have not heard any mention of the NCM300 by HVAC contractors near me (Eau Claire, WI). I have a Bryant Plus 90i from 2000-- it is connected:
W2 -- Empty
Com 24V -- 2 red wires
W/W1 -- 1 white wire
Y/Y2 -- 2 wires (White and Blue)
R -- 1 red wire
G -- 1 green wire
HUM -- Empty

Thank you.