The answer to 'why is my pressure regulator burst pipe' is that a burst pipe caused by a failed pressure regulator is a common plumbing issue. Pressure regulators are installed to control the incoming water pressure and prevent it from exceeding safe levels for your home's plumbing system. Over time, the internal components of the regulator can wear out, leading to a sudden increase in water pressure that can cause pipes to burst.
Some common symptoms of a failed pressure regulator include unexpectedly high water pressure, leaks or flooding, and a noisy or vibrating water system. If you suspect your pressure regulator is the cause of a burst pipe, it's best to call a professional plumber to diagnose and replace the regulator as soon as possible to prevent further damage.