To repair a Goodman gas furnace, check the fuses and circuit breakers, clear the debris from the filter and clean the flame sensor. Other potential repairs include removing blockages from the flue and switch hose, adjusting the gas pressure and replacing the igniter.
If the heater is not turning on, ensure that the temperature is set at least 3 degrees above the current ambient temperature, and examine the circuit breaker, fuses and outlet if it is still not functioning. If the LED light flashes four times consecutively, the filter may be blocked and should be cleaned thoroughly. Ensure that the pressure hose and flue have no blockages. A pilot that lights but does not remain lit may signal a coated flame sensor. Clean the sensor with a damp cloth before lighting it again.
A LED light that flashes seven times indicates a low flame, a problem that may be fixed by turning off the furnace and adjusting gas pressure. For eight consecutive flashes, ensure that the igniter is connected correctly, and replace it if necessary. If these fixes do not solve the furnace's issue, or the furnace is cold to the touch or leaking even with a lighted pilot, contact Goodman to schedule a visit from a repair technician. All repairs and replacements should be performed by an experienced HVAC technician whenever possible to avoid safety risks.