Have amana furnace model GACA070AX30. FURNACE HAS A 5 FLASHES ON ERROR CODE. FURNACE STARTS UP REACHES THERMOSTAT SETTING, BURNERS SHUT OFF BUT FAN MOTOR WILL NOT SHUT OFF. IT ALSO TRIPS ROLLOUT LIMIT

If you have a switch that can manually turn on the fan, try it to verify the fan works. This is what I think is happening. The normal operation should be thermostat calls for heat, inducer fan comes on, pressure switch closes, igniter glows, main burner ignites and then in 30 or so seconds the fan comes on and stays on until the thermostat is satisfied. Once the thermostat is satisfied the burner shuts off and the fan runs for approx 120 seconds then shuts off. I think the control board that automatically turns your fan on is faulty. On most modern furnaces if the auto fan control fails and the furnace gets to hot and limits, when the limit opens and shuts off the burner it also energizes the fan motor to cool the heat exchanger.

If the furnace is cycling on and off and not reaching temp there is a problem in the control circuit. If the thermostat is not satisfied the furnace should be running without shutting off in which case the capacity of the furnace is inadequate because of size or problems reducing the capacity. This could be caused by an increase in home size, poor air flow (dirty filter, loose fan belts, fan running slow, obstructions in the duct), dirty heat exchanger or burner, reduced gas flow, over temperature switch bad causing the burner to shut off early, or a few more technical reasons. You may do well to call a technician to troubleshoot this problem.

IT SOUNDS LIKE THE FAN CYCLE RELAY OR BOARD IS NOT MAKING THE FAN COME ON WHEN IT SHOULD THE BURNER SHUTS OFF PROBABLY BECAUSE IT REACHES THE HIGH LIMIT.

How many degrees before it reaches desired temp, does it shut off? A thermostat is designed to shut the furnace off a couple/ few degrees before it reaches set temp. It has what is called a heat anticipater, which shuts the burner down, and lets the blower use the remaining heat from the heat exchanger to bring it up to desired temp making it more efficient. If it is more than a few degrees, replace the thermostat. You can jump out the red and white wires to confirm the faulty thermostat. If by doing this, the furnace never shuts down, until you separate the red and white wires. That confirms a faulty thermostat. Hope this helps someone.

Sounds like the heat anticipator in your thermostat is either bad or out of adjustment. Turn of the furnace power. Remove the thermostat wires from the thermostat. Turn the power back on. Connect the white and red wires together. The furnace should start up. Let it run a couple of minutes. Then disconnect the wires. The burners should shut off immediately. The blower will continue to run for 60 to 360 seconds then shut off. If this happens replace your thermostat. If the burners continue to burn, then your problem is either the furnace or the thermostat wires.

Go to the thermostat and switch the fan to "ON", if the fan runs you have both high and low, 24 volt control voltages, go to the unit and look for a flashing code by the blower assembly, there will be a tiny port to see through on the lower door of the furnace, this will give you any codes telling you what has failed.

Coleman Evcon Furnace Error Codes


this will help you

Try blowing air thru the pilot tube. You may have a spider web in the burner tube.

You can make sure it is not the thermostat by crossing or jumping the R and W terminals (or associated wires) together. This will keep the furnace calling for heat. As it is approaching set temperature, get in front of the furnace and inspect the air filter to make sure it is clean, watch the control module for any error codes that may be turning off the system prematurely.

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

the reason he told you not to cycle the power is because some where there is a flashing light that he can decode and tell him where to start looking for the problem. Call him next it happens and don't touch the power or the stat until he gets to see the unit.