I have a 3 1/2 yr. old Reliance Water Heater. Model #54020Rs960, Serial #J96373516. Recently we replaced the heating elements. Ever since we replaced them the T&P valve has been leaking. We have already replaced the T&P valve twice thinking they were bad. Is it possible that the new heating elements are causing the problems? We have the thermostat set between Hot & A. I had it lower but the water was not hot enough. The heating elements are the same wattage which are 4500, but the heating elements themselves are longer than what we took out. Could that be the problem?
The elements have nothing to do with the problem since they heat under the control of the thermostats. You are either getting a pressure buildup from the expansion of water, or the water is too hot. If the problem is expansion due to the presence of a pressure reducing valve on your building’s main water line, then you will have to install a diaphragm tank in the system somewhere to absorb that excess pressure.