Raypak 206a pilot light intermittently staying on

[Ratman67]

Raypak 206a water heater. Getting a “flame w/o CFH” when the ignition sequence begins due to a pilot light that remains on after the previous heat cycle. This is an intermittent issue that happens every day, sometimes every other day. When the pilot light isn’t on, all normal ignition cycle sequence seems fine. Spark, pilot lights, main burner lights and runs until it reaches temp. But randomly the pilot stays on. Blow out the pilot, it starts right up.
Think it could be the pilot light part of the valve that is sticking open. Any other ideas to check before purchasing a new valve???

 

[ajw22]

Welcome to TFP.

Lets see what @swamprat69 thinks when he wanders by.

 

[swamprat69]

The common terminal on the gas valve should be labeled either "C" or "MV/PV" ( Robertshaw or Honeywell ). If you have 24V between ( C or MV/PV ) and PV then the problem is with the control board. If there is no 24V between ( C or MV/PV ) and PV when the pilot is lit, then the pilot solenoid in the gas valve is sticking open intermittently and you would need to replace the gas valve. This would be if the pilot is lit when it should not be lit.