Gas and Oil Home Heating Furnaces - Amana - Loud Knock

:confused: I RECENTLY CAME ACROSS AN AMANA #GUX-X (UPFLOW) FURNACE THAT MAKES A LOUD KNOCK SHORTLY AFTER THE THERMOSTAT REQUESTS HEAT. THIS IS MOST PREVELANT WHEN THE FURNACE HAS RUN FOR A WHILE, (LIKE ON MILD DAYS). THE IS AT THE FURNACE, & COMES DURING THE IGNITION PHASE, BEFORE BURNER LIGHTS. THE GLOW PLUG DE-ENERGIZES, THEN AFTER A FEW SECONDS, THE IGNITOR GLOWS AGAIN; BURNER COMES ON, AND EVERYTHING IS NORMAL. ANY SUGGESTIONS!!! (FORGOT TO MENTION THAT THE CONTOL MODULE WAS REPLACED RECENTLY). WAS TOLD KNOCK WAS NOT THERE PRIOR TO CONTROL BEING REPLACED. THANKS


EARL - HAPPY HOLIDAYS

hard to say, ej. as i understand noise occurs between call for heat and ignition? try to give more info, how old, is that a 90 or 80%er? upflow or horizontal, where is it located...etc.

Have you checked the main fan pulley on the motor or on the fan itself is not lose on the shaft(s) . Also check for lose mounts on the motor or fan assembly.