i have a goodman furnace that won't stay on .. the glow plug comes on and ignites the heat box,, it will run then shut off ...after it gets to desried heat ,,, then when u try to get it to run again it's like it shuts down after igniter being lit for about 10 secs,, i've replaced batteries in thermostat and had new filter installed aswell... it seems every time i go to loook at it i can get it to run as normall then my tenent calls and tells me it wont start after coooling of the house

Try cleaning the flame sensor.

thanks hvac1000 seems to have done the trick u rock my friend

Well, I have to say that I'm simply amazed that cleaning the tarnish off of a piece of metal would so affect a "system" :) . I've tripped the system 4 times and its started flawlessly. I'll know in the morning when it wakes me up because its not working right.

Thanks for taking the time to post your answers here.

Larry