I changed the water heater thermocouple yesterday and lit the pilot light. Had plenty of hot water for 24 hrs. Now the pilot light went out again and had to re-light it. Is this a fluke or is there possibly something else going on?

Any chance there is air movement blowing out the pilot? Did you get the combustion chamber doors in place properly?

There is a small draft coming from the floor drain. Not enough to blow flame out on a candle. And chamber doors are fully closed.

Put some water in that floor drain first. Now, do you have a sealed combustion heater? If so, it sounds like the combustion intake is plugged which will cause the unit to run out of oxygen. What make and model and year water heater do you have?

Called in the professionals. Turned out to be gas control valve. But water heater is 11 yrs old and we have hard water, so instead of changing valve and taking the chance of tank going bad we replaced it all

Thank you for the help and advice!! Much appreciated

Hey, you made the right call. Thanks for the update.