New moen posi temp cartridge in basement tub/shower. Basement tub/shower head heavy leak. Replaced moen posi temp cartridge. No leak. New thermal expansion tank above water heater. Old expansion tank had ruptured. Replaced with new two gallon thermal expansion tank. Customer has water pressure at 82-84 psi. Pressure may vary, however it is proof. That existing Pressure Regulating Valve has failed. Highly recommend replacing as soon as possible. New expansion tank will help with thermal expansion but does not assist with helping overall incoming pressure. Will include estimate for new PRV with invoice.