Before leaving on vacation I set the thermostat on my hot water tank to VACATION setting. Having been gone for 1 month, upon my return I set the tank back to my normal setting...Medium hot. I just noticed that my pressure relief valve discharged about a pint of water. HWT is 40 Gallon Gas. I have drained another quart of hot water from the pressure relief valve. No discharge so far. Should I be concerned if no further discharge occurs?