the tank is 6 years old and have not had it leak out of t and p since it was purchased. recently replaced the thermocouple and as I was turning it on I lit the pilot and forgot to put it to a setting. so the next day (only the pilot has been lit for like 12 hours. I get a text saying we had no hot water. turned the heat on and we noticed the t and p was leaking. why? with it only being the pilot did the tank not turn off when it got to a certain tempature and caused the t and p to trip?