How Do I Troubleshoot a Goodman GDS80904BNA?
- 1). Note the flashing LED on the integrated control module. Its flashing once, twice, up to eight times, continuously or not flashing at all will help diagnose the problem.
- 2). Check power if the furnace fails to operate and there's no LED flashing. Check for a blown fuse or tripped circuit breaker. Ensure 24-volt power is supplied to the integrated control module and its own fuse hasn't blown. Replace the control module's fuse with an automotive fuse, if available. Assume an internal fault in the integrated control module and replace it if the previous actions do not correct the problem.
- 3). Ensure the gas supply is open if the furnace won't operate and the LED is flashing only once. The furnace locked out because after one initial start attempt and two retries, it wasn't able to create a flame. Another cause may be insufficient exhaust airflow, so also check the circulator blower speed and performance as well as the flue for blockages. After one hour, the integrated control module will automatically attempt to restart on its own.
- 4). Check the induced draft blower pressure switch for sticking if the furnace fails to operate and the LED on the integrated control module is blinking twice. This either means the pressure switch is closed or there is a short in the pressure switch circuit. Replace the induced draft blower pressure switch with a replacement part or repair the short, respectively.
- 5). Check the pressure switch hose for blockage, pinching and improper connection if the blower runs continuously with no other furnace operation and the LED flashes three times. The pressure switch circuit is not closed. Also inspect the flue for blockages, pinches and proper termination. Ensure all wiring is secure and properly connected.
- 6). Check for blocked filters if the blower runs continuously and there are four LED flashes. The primary limit circuit is open due to improper airflow, so ensure all vents, filters, ductwork and flues are clear. Five LED flashes with the blowers running but no heat means a flame was sensed but no heat was called. Correct a short in the flame sense circuit, check for lingering flame or verify the gas valve is not closing too slowly.
- 7). Check burners for proper alignment if there's no furnace operation and LED flashes six times. The rollout limit is open because the flame is rolling out. Also check the induced draft blower for proper airflow. Seven LED flashes with normal operation indicates the flame sense microamp signal is low. Sand the flame sensor clean because it's probably covered with a coating of oxide.
- 8). Check and correct wiring from integrated control module to igniter if the furnace won't operate and there are eight flashes on the LED. A problem exists with the igniter circuit, meaning loose wiring or a bad igniter that needs replacement. Continuous flashing of the LED means switched polarity of the 115-volt main power or the 24-volt power to the integrated control module. Check those wirings for proper connection.
