I replaced the thermocouple. It's installed correctly. I get a nice blue flame. No drafts. No water dripping on pilot light. When I go to light pilot light, I hold down the knob for 60 seconds, as soon as I let up on the knob the pilot goes out. Yes, the gas supply is turned on. Is this a faulty gas control valve? How do I test it? I had no trouble replacing the thermocouple so I may be able to replace the gas control valve?