Pilot light will not stay lit. already replaced thermal coupler. 6 gallon

Try spraying some WD-40 in hole where thermocouple attaches to gas valve, then twirl a small piece of steel wool in your fingers and insert it in that same hole and twirl it as you push it in to clean surface where thermocouple makes contact. Then blow out with compressed air if possible and then re-install thermocouple fitting snuggly. If that doesn't do it, you'll have to get a new gas valve/control.

the white rodgers gas control needs to be replaced;
the way it works is: the thermocouple opens the pilot gas circuit and, holds it open
when it heats up by creating a magnetic field in the gas control then: when you turn
the knob on the gas control to "on" a valve inside the gas valve opens the main gas circuit and, electricity supplied by your RV keeps it open.
the main gas coil inside the gas valve is defective and, can not hold the main gas circuit to the burner open anymore.

Any RV sales and service dealer can get parts for you, if they don't already have them in stock. Is the pilot staying on at all? If yes, what happens when you turn from pilot, to On? One easy thing to try is undo thermocouple (probe that sits above pilot flame) from gas valve (3/8" wrench) and clean the end of the thermocouple with fine steel wool, as well as spray some WD-40 into the hole it came out of, and give it a blast of compressed air after to clean it out as well. (protect your eyes) Then re-install the fitting and snug it up good, and try lighting again. You may get lucky that it's just corroded or dirty, and this may cure that.

So are you saying that the first initial lighting of the pilot, without turning to on, works o.k., good flame etc, ? If not sure, try lighting pilot only, and leave setting at pilot only, and see if it's a good flame, and get back to me.

Please confirm which model you have. Heading says DSI (electronic ignition) and it sounds like you are describing a manual light with thermocouple?

Yes. If your using it in an RV, your converter can supply the needed 12 volts, if it's not already there.

I'm having the same problem! Bought new thermacoupler and thermostat and it still won't stay lit.

sounds like the wiring is backwards check the wiring
also check the thermo coupler

Kenny did you change the thermo coupler?

I would remove the heating element from the hot water tank. Take a look at it as it is probably fried from due to turning on the power to the tank when there was no water in the tank. If it looks ok still do a continuity test on it. I believe that is your culprit.

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