I have 2 GE 28 gallon water heaters, both of which have the same problem. The water heater is turning off after a while, and I have to light the pilot again to got hot water. What could be causing the pilot to extinguish when the main burner shuts off?
'Gusting" of the combustion air can be caused if the shrouding around the base of heater is loose or missing. Such gusting can knock out the pilot.
Another cause of pilot extinguishing is a too rapid start up of the main burner. Usually there is a small baffle around the pilot, protecting it.
Too high a pressure of the gas would also cause a too large main flame. This would have to be checked at the meter by a qualified technician. This, obviously, is a dangerous condition. Other gas appliances (gas stove) might reveal this condition.
Conversely, too low a pressure (and therefore, low gas flow) might make the pilot more sensitive.
Once the pilot is knocked out, cooling of the gas valve thermocouple will prevent restarts.