Cassette-type fan coil units are mainly composed of centrifugal fan blades, coil (heat exchanger), and microcomputer control system, serving as terminal devices in central air conditioning systems. They are widely used in hotel, restaurant, factory, exhibition halls, shopping malls, and office buildings, among other multi-room or large-scale industrial and civil buildings, for air conditioning purposes such as cooling, dehumidification, and heating. They create a fresh, tranquil, and spring-like environment year-round for work and living. These units have an oblong, sleek design, are aesthetically pleasing, and feature a new-type aluminum alloy centrifugal fan wheel. They operate quietly with low noise and are safe and reliable, with a long lifespan. Each unit undergoes pressure leak testing: the inlet and outlet water pipes (collecting head) are made of forged brass, ensuring reliability and durability, with a service life exceeding 45,000 hours.