Homeowner attempted fixing master bath toilet himself and a bolt snapped off so he wanted a professional to finish the work arrived and found the downstairs toilet was running constantly checked the pressure at 120 indicating failure with the PRV the PRV was 15 years old found the expansion tank was compromised due to the high pressure gave price to replace pressure regulator expansion tank in rebuild toilet with customer supplied parts. performed work tested with no failures at time of service house pressure set at 65 expansion tank set at 65.