[Mikendebbie]

When you say you removed the side panel - do you mean you took the metal side of the water heater box off? Or did you remove the basement bulkhead wall which exposes the side of the water heater? Pic below is the sidewall of the water tank for my unit.

When you are listening to it - do you hear the burner fire and then turn off (which would be when you loose hot water)? Or you could feel the heat blowing out of the burner exhaust vent outside.

Are you the original owner?