I have a Coleman Evcon heater/ model DGU08012UB. The flame comes on for a few seconds and then it turns off. Then cool air blows out. This process continues. Can anyone help me with fixing this issue. Is it a common issue? Thanks for your help.

This is a natural gas heater and the red light on the bottom blinks 10 times. Not sure what that code is.

Try cleaning the flame sensor.

How do I locate the flame sensor?

Here is what they look like but there are others.