I have a State Water Heater Censible model # PRVNOVT1D, the pilot light keeps going out, there are no obstructions and everything is dust and dirt free. Any suggestions?

Assuming that you light the pilot, and it appears to be working for awhile, and then shuts off, there is a sensor above the pilot light that shuts off the gas if it determines the water temperature is too high. The pilot light must be re-lit if that happens.

If the pilot won't stay lit, there is a thermocouple directly in the path of the pilot light that must stay hot in order to tell the controller to deliver the main gas. If the thermocouple is faulty, you won't get your main gas, and the pilot light could go out.

A significant draft could extinguish the pilot light, but you'd know it due to hurricane wind speeds.

Mostly commonly the thermocouple above the pilot light needs replacing.

Where can I find a replacement knob for the control valve on my PRV 40 Noc 52C?