So I recently installed a new Bradford White 55 Gallon 80k BTU Water Heater RG155H6N. When not using the water for a while (hour or more), then running a very small bath for the kids, the hot water seems to run out extremely quick, definitely way before the limitations of the 55 gallon BW WH. I'm not sure what it could be, my old 50 gallon handled this task no problem. The thermostat is set to "B" which seems to be about 130* give or take (I checked with a thermapen at closest location). I'm not sure what else I can check. It almost seems like the initial few gallons (guessing on how many) come out hot (at the desired temp), but then the water turns to warm very quickly, not cold, but definitely not hot. I have no idea what I can troubleshoot.