We filled our tub recently and turned everything on and found that we are getting no voltage off of H1 and H2 from the heater relay board to the actual heater. We bypassed H1 and H2 to verify that the heater is actually working, and it was. It seems as though it could possibly be a bad sensor on the heater itself? I'm not sure how to test that. If anyone has any ideas it would be greatly appreciated.