I just moved into a new house last week and I'm having an issue with the upstairs thermostat. I'm a first time home owner and looking for some guidance on how to troubleshoot the problem. An explanation of the issue is below.

We have two heat pumps and two thermostats - one for downstairs and one for upstairs. The downstairs unit works great but the issue is with the upstairs thermostat.

The heat was working fine for the first two days, but when I came home from work on Friday I went upstairs and noticed it was stifling hot. The thermostat was set at 60 but the room temperature was 90 and was continuously blowing out of the vents upstairs. So the heat must have been blowing all day and it never shut off when it reached the desired temperature. The settings on the thermostat were at Auto Fan and Heat, which are the correct settings to my knowledge.

To get around the problem, I just turned off the upstairs unit and it did shut off for me. However, the same thing happened the next day when I turned it on again - the heat kept running after reaching the desired temp...in excess of 15 degrees. This time, however, the heat would not shut off when switched to the "off" position. I left it go for about an hour and tried it again and it then finally did shut off.

I am now afraid to turn it back on because I'm worried I will not be able to shut it off.

Here are the specs on the thermostat

white-rogers comfort-set standard 1F89-211 pro-spec #80h∅w

Any advice that can point me in the right direction would be a huge help. Thank you!

- Nick