My XR80 is not heating. The ignitor is glowing and the fan runs but there is no heat. 1) How do I know if the ignitor is hot enough. 2) Is it a gas valve. Also the re light was originally blinking twice t snow blinking continuously Any suggestions?

It is not easy to diagnose from what you offer. Newer heaters have many safeties built in. Could be as simple as the flame sensor or an expensive computer board. Count the flash codes and look at the inside of the air handler for the codes. I had one not too long ago that was just a loose wire on the air handler.