Shut down water to home at meter. Excavate around piping to shut off valve buried in yard. Cut out and replace shut off valve in ground. Replaced three-quarter inch PRV on CPVC piping in crawlspace. Replace 2.5 gallon thermal expansion tank and support. Once all items are repaired and replaced pressurize system slowly and bleed out air. Test all new connections for leaks. Replace standpipe access around valve and tamper down dirt around piping.