gas value won't stay open on a goodman furnace gmpn100-4
The gas will shut off shortly after the hot surface ignitor (glow plug) turns off. I can force the valve to stay open to let the furnace heat the house. This problem is intermittent and after forcing the value to stay open, the furnace will run normally for 6-12 hours and then needs attention again. I've replaced the computer board with no luck. The last part in my thinking is that the valve is defective. Any assistance anyone has with this would be appreciated.