Like I said earlier, I had this EXACT problem. Open you tank valve slowly. If you crank it open, the Emergency Shutoff Valve will restrict the flow of gas.
What immersion rod? A heating element rod? An oxygenation wand? I wouldn't think that a heating element need to be sanitized, just cleaned. An oxygen wand tip should be boiled for 10 minutes or more in just water to sanitize it.