Red Seal Plumbing Practice Exam

The pressure relief valve (A) releases excess pressure from the boiler, while the flow switch (B) controls the water flow to the boiler. These options do not provide protection from excessive temperature. The pipe thermostat (D) measures the temperature of the water entering the boiler, but does not have the ability to protect it from excessive temperature. The limit control (C), on the other hand, is specifically designed to monitor and control the temperature of the boiler, making it the correct answer. It helps prevent the boiler from overheating and causing potential damage.