Have a Bryant 80 plus furnace. Fan works fine. But it's blowing cool air. I've changed the thermostat setting to have the furnace try and make the temp significantly higher than the current temp. The LED flashes 1 short, 3 long. Cleaned the filter. Air flow seems to be fine.
Any clues?
-Thanks.

I have the same issue, 1 short 3 long led, air filter changed to new one, fan blowing fine but It's COLD air. :(

Help

Thanks.

Code 13 is a limit circuit lockout. If the primary limit switch is stuck open, something is causing the furnace to overheat (clogged filter). This switch is not designed or intended for frequent/repeated cycling. Try tapping the butt of a screwdriver between the terminals to reset. If this doesn't work, you may have to remove the switch & tap the disc against a hard surface. You will have to cycle power off/on to cancel lockout.

KC 13, that's almost exactly what I had to do. I take switches out and put those back on after tapping a hard surface. It works like a charm.

Thanks a lot guys.