HI
My Goodman furnace will not (repeat cycle) . Furnace will operate, but after it reaches
The desired HEATING TEMP, it shuts down and will not recyle, when the temp drops.
I then get the 3 blink flashing light---indicating (pressure switch is stuck open).
Then I turn the furnace off for about 1 hour then adjust the thermostat to desired temp
And the furnace will ignite and bring temp up to desired setting.
Appreciate your help, and I thank you. Mike

Flue pipes are possibly the wrong size, best guess.