I just got some info that may help. See this google doc https://docs.google.com/spreadsheets/d/1VQ5RKnu5wZUIdHfiWDm2ZcqK4KqLm_2zuZBcYDqasQI/edit?usp=sharing There are some wires that look like they may be touching, I will ensure they are not tomorrow. See the image in the google doc.
My house heater (gas) will turn off after running for some time but before reaching the temperature set at thermostat. I then have to lower the temperature at the thermostat below the current house temperature (I hear a loud click from the return register) and then back up to a level above the current temperature. The cycle then repeats.
The thermostat reads 68 but is set to heat to 72. The heater is off.
I lower the thermostat to 67. I hear a click.
I raise the thermostat to 72. The heater turns on.
Some time later the heater turns off, but it does so before reaching the level set at the thermostat. I repeat the cycle.
Last year I had two separate techs come out and they did not find any issue. One adjusted something and the issue seemed to be better for a while but neither fixed the issue.
Any thoughts on this or is there a stack exchange better suited to this question?
The heater is original I believe, installed in 97. It is gas like I said and I change the return register filter regularly.
Edit - Thermostat is an emerson up500W. It is set to a single stage gas heater and the reversing valve position is set to "O" (but "B" is an option). The device says the batteries are full. https://ibb.co/pnGbvQR https://ibb.co/k3d8xJz https://ibb.co/bdfXgmL
I apologize but I do not know anything about the furnace. I will crawl up into the attic and take a look tomorrow and get a model number.