The pop up reminder has been on my thermostat since October.
However the furnace couldn’t hold temperature and started short cycling so I had to. Unfortunately that doesn’t seem to be the problem so I may need to call a guy (it’s always to replace the control board but I have yet to find a way to confirm that before spending $400 to do it myself)
Short cycle probably isn’t the control board. More like something isn’t working right (sense unit for flame, pressure switch for evacuator blower, etc).
Furnaces are fairly simple (at least in number of components), and the board will flash an indication of the error. Pull the cover off and look at the diagram on it - there should be a chart showing how to read the flashes.
Side note: it’s probably been short cycling it’s whole life, since most are way oversized, and installers don’t bother to adjust the ductwork/dampers or the blower speed. Most likely the blower is configured for max speed, and it would work better at low speed.
Everywhere I’ve lived this has been the case, and configuring the blower to low speed worked fine, and the air conditioning actually worked better (too high of a speed and the air exchange rate is too high to dehumidify the air properly).