A 4 Ton RTU (Roof Top Unit) is a type of air conditioning system that is designed to be installed on the roof of a building. It is typically used to cool larger commercial and industrial buildings, and can provide cooling for up to 4 tons of air. The 4 Ton RTU is composed of several components, including a compressor, condenser, evaporator, and expansion valve. The compressor is responsible for compressing the refrigerant gas and transferring it to the condenser, where it is cooled and then sent to the evaporator. The evaporator then absorbs the heat from the air, cooling it down and sending it back into the building. The expansion valve then controls the flow of the refrigerant, ensuring that the right amount is used for cooling. The 4 Ton RTU is an efficient and cost-effective way to cool large buildings, and is becoming increasingly popular for its energy efficiency and reliability.