What type of switch is used to keep refrigerant levels within safe limits on some systems?

• A. Pressure switch
• B. Flow switch
• C. Float
• D. Temperature switch

Answer: (C)

Sensing and controlling liquid level is essential to protect equipment and ensure reliable operation. A float switch uses a buoyant float that rises and falls with the liquid height; when the liquid reaches a preset level, the float moves a switch to start or stop a device, or to trigger an alarm. This direct response to liquid height is exactly what’s needed to keep refrigerant levels within safe limits in systems that include a receiver, sump, or reservoir, preventing both overflow and starvation of the system.

Other options don’t measure or control level directly. A pressure switch monitors pressure rather than how full a vessel is. A flow switch checks that refrigerant is moving, not how high the liquid is in a container. A temperature switch reacts to heat, not to liquid height.