Came out to call for a system not heating properly. Customer stated that the unit seemed to be running, but sounded like it was only running for about 60 seconds. I checked the unit over and found the system continually restarts after the gas valve receives voltage. Checked voltage to gas valve and it had 24 volts. I found the unit wouldn’t drop out and restart when the wires to the gas valve were disconnected, and would try to complete a full cycle. Gas valve has a short in it and is causing the control board to fault out. Discussed with customer about repair needed. Picked up new gas valve and replaced the existing one. Wired it in and made sure sealant was goo on all gas connections. Cycled system on with new gas valve and it worked without any issue. Made sure gas pressure was correct and that the system was cycling properly. Unit is now operating correctly.