Janitrol Model GUE080-4 REVS, Serail Number 891282538.

Unit will not start.

1. No spark - Spark module tested good.
2. Fan works
3. new thermostat installed 1 year ago

What should I look for?

If the moduele tested good there should be spark. The high voltage leed from the moduale to the spark rod on the pilot could be defective.

You can jump R (RH) and W on the furnace to see if that gets it going. That just jumps the thermostat out of the circuit. If it works then it is in the thermostat or wiring. If not post back.