The answer to 'why is my pressure regulator burst pipe' is that a burst pressure regulator is often caused by high water pressure in the home's plumbing system. The pressure regulator is designed to lower the incoming water pressure to a safe level for the home's pipes and fixtures, but if the pressure is too high, it can cause the regulator to fail and burst.
Some common symptoms of a burst pressure regulator include low water pressure throughout the home, water leaking from the regulator, or the sound of water constantly running. If the pressure regulator bursts, it's important to shut off the main water supply to the home immediately to prevent further damage. In some cases, the burst regulator may have caused damage to other plumbing components as well.