T-Stat Fan Recirculate Temp Based


I am trying to setup a Honeywell RTH9580 to recirculate air based on temp. The system in question is a single air handler/condenser central air system. What will happen is the 2nd floor tends to be much warmer then the first due to the T-Stat being located on the first floor. So in an attempt to help this situation, I installed a Xiaomi temp sensor on the second floor and setup Core to control the house fan based on a set temperature. But what I found was that the thermostat did not change modes from Auto to Fan On. No matter what I tried, Core just did not adjust the fan mode. I could in fact adjust the mode in the Smartthings app though.

Wondering if anyone has some recommendations for a smart app or if there is a trick to get core to work properly. Thanks.

(Ron Talley) #2

I would first, manually adjust the registers to even out the temps.

Second suggestion is to try webCoRE.


This is actually for my dad’s house and he does do this manually already and manually turns the fan on when needed. I was trying to automate this process.

(Ron Talley) #4

Meaning, manually adjust the registers (the thing that the air comes out of) so that the temp balances out upstairs and downstairs.

Having a temp sensor in the room helps big time with this but using the fan, will not give you the results you are looking for. Either way, try webCoRE.


Yes, he does adjust the registers for summer/winter, they are old style so they must be physically flipped to direct air upward for the summer. Running the fan does actually does help, its just a manual job at the moment.

I will try WebCore, but was avoiding this because it is still in beta if I am not mistaken. I also wanted the simplest way to set this up, as my dad will not be managing the system and it needs to be as little hands on as possible. I also figured this is a very simple objective that there may already be a smartapp app available.

(Ron Talley) #6

Post your Piston. Let’s take a look. Seems like a very easy Latching Piston.

Temp Sensor is greater than or equal to X
Using Therm
Set Fan Mode to On

Temp Sensor is less than X
Using Therm
Set Fan Mode to Auto


This is exactly what I had setup, but the piston would just sit there and not trigger the T-Stat. It seemed like an access issue to me possibly.

Edit: The piston would show running also.

(Ron Talley) #8

Dang. Well might be a bug in CoRE. webCoRE is super easy to install and the time spent trying to get it to work in CoRE could be used to install webCoRE and build the piston over. Cool thing is that you can play with the Piston from anywhere without the need to be logged in to the SmartApp.


Yeah I will check out webCore,I know it is very powerful and welcome upgrade over Core.