We just installed a 70,000 BTU goodman furnace and it worked fine then it gave the code of 4 flashes. We tested eveything and still locked out.

My book says 4 flashes = a open limit control. Look on the inside of the blower door for your wiring diagram and post exactly what 4 flashes mean for your furnace.

We checked the open limit control and it works fine.

If you just installed the furnace I would look for a problem with the install. Look over your work again and pay close attention to the exhaust size,length,and termination.

It was installed profesionaly and he checked evrything. Exhaust is 2 inch pvc and runs 15 feet.

Exact model number?

Gmh96/gch9

Here is your complete service manual. You can use this to track down your problem. I suggest you keep a copy of this on your computer for future reference. This manual is also for other units so make sure you are using the correct section for your model number.

http://securenet.goodmanmfg.com/pdf/infoPdf/Lit/RS6610004R4.PDF