Called for leaking tmp line on water heater. Upon further investigation found that the Prv has failed, pressure was over 100 psi. Replaced PRV and 8 year old rheem water heater. Installed new 50 gal rheem gas water heater with 10 year warranty. Installed new expansion tank, strapped and supported to the structure. Installed new ball valve and water heater pan. Purged lines of all air. Tested for leaks, no leaks.