If you install a flow detector with an auto shutoff valve with the intention of it shutting off the main water line to the house when it detects a burst pipe, it will indeed stop the water flow to the entire house if a burst pipe is detected. This is the primary function of such a device—to prevent extensive water damage in case of a sudden and significant increase in water flow that indicates a burst pipe or a major leak.
However, this means that when you use the shower or the washing machine, the flow detector may falsely detect an abnormal increase in water flow (depending on its sensitivity and accuracy). This could potentially trigger the auto shutoff valve, cutting off the water supply to the entire house.
To avoid this inconvenience while still maintaining protection against burst pipes, it's essential to set up the flow detector with appropriate sensitivity and flow thresholds. Some modern flow detectors come with adjustable sensitivity settings, so you can fine-tune the device to differentiate between regular water usage and a burst pipe situation.
Additionally, some flow detectors are designed specifically for particular areas of the house, like near the main water supply line, which would reduce the risk of false alarms from isolated water use in individual appliances.
Before installing a flow detector with auto shutoff, make sure to read the product specifications and guidelines, and consider consulting a professional plumber to ensure it's set up correctly and tailored to your specific needs. It's essential to strike a balance between preventing water damage and maintaining practical water usage for daily activities.