Came out to replace a main board. Board was bad, however, unit still wouldn’t ignite. We have a bad pressure switch. There is proper voltage but not the right amount of water column. I tried to do other test as well to make sure that was the issue. Gas valve had 24v and hot surface igniter was lighting. Pressure switch wouldn’t allow flame to ignite due to the water column. Myself and Jerimiah were able to temporarily get the unit to heat, however, it will fail again. We need to return with parts ASAP.