Over the last week have ran into 3 D-40 seabrooks that were not lighting the main burner. Initially I thought it may be a thermopile so checked millivolts on the thermopiles 500mv+ with pilot on, then checked connections, dissasembled connections added a brand new thermopile connection and hit with pilot no bueno.

So jumping the valve while getting the correct millivolts didn't do anything, on one of them it kicked on then died out, So on each occasion called tech to make sure was doing the right tests to verify that gas valves indeed were faulty. I understand Gas valves are heavily misdiagnosed and wanted to make sure I wasn't throwing parts at the problem. The only other tests would be ohms on the valve and or applying the famous 9v to jump or shock it open

The weird thing for me and what caused me to call tech on 3 separate occasions was the fact that the same model on 3 systems in a week have went down and it seemed pretty odd. Question? With your experience guys when these valves go down what would be the ultimate verification of failure beside the tests performed above?

Have a cool one