Pressure relief valves on water heaters are set at about 150 PSI. That 10GS05 pump will only build about 90 PSI max. You need a relief valve on the pump set at about 75 PSI. This is not to protect your plumbing, but to protect your pump. When your pressure switch points melt together from excessive cycling, the pump won’t be able to shut off at 60 as it should. The pressure relief valve will dump enough water to keep the pump from melting down, before you figure out what is going on. You also need to plumb the discharge of this PRV to a place you can see. It is your high-pressure alarm. When you see water coming out of the discharge of the PRV, you will know the scenario I described above has happened, and the PRV has just saved your pump.