tpr valve leaking

[lewe]

my tpr valve only leaks a small amount of water when the hot water heater is heating up . i have replced the tpr valve and it still leaks. i have checked the water pressure at an ouside faucet and the pressure is between 70- 80 psi unless the water heater is heating and then it has gone as high as 150 . i do not have a expansion tank and have been told my numerous plumbers that they dont use them . the water heater is only 3 years old . i have been told maybe i need a pressure reducing valve installed at the water meter . please help.

[jadnashua]

classic symptom of the reason an expansion tank is recommended. You would probably notice that you get more water out the valve if someone takes a long shower or otherwise empties the tank so that it has to heat a large volume of water. 70-80 pounds static is at the max recommended. An expansion tank will solve this annoyance. What you have is to be expected under the current conditions. My unprofessional opinion.

[RioHyde]

Install an expansion tank and I do believe that will take care of the problem.