1. Today it stopped heating the house; three red blinks were visible. The instructions say this means the "pressure switch is stuck open".
2. I could see the "top" (smaller" motor wasn't spinning) but the bottom (bigger) motor was spinning; so, I guessed, there was no vaccum to the pressure switch - hence - the pressure switch was stuck in the open (off) position.
3. To test, I removed the hose from the top (smaller) motor & sucked on it.
4. This self-induced vacuum caused the diaphram to move which caused the mechanical switch connected to the pressure valve to close (I could see the switch move when I sucked on it).
5. The flame ignighter heated up and the gas started burning. The three blinking red LED signal went out; I thought I "fixed" my furnace.
I cycled the power a few times while I cleaned the filters and blew dust from around the wires.
6. Then the Amana Air Command 80 gas-fired furnace stopped heating again; this time, four red blinks were visible!
7. Now the opposite ocurred; the "top" (smaller) motor was now spinning but the bottom (big) motor was not spinning. No air was circulating through the house.
8. Four blinks indicate an "open Limit Control (primary or auxilliary)".
8. If I cycle the power to the furnace, it works for about ten minutes and then the bottom (big) motor stops spinning and the four blinks start again.
I have a few questions: a) How can I troubleshoot this Amana Air Command 80 gas-fired furnace? b) Is there a reset switch somewhere? c) Is there a maintenance guide on the web somewhere?