What condition causes a valve to 'hunt'?

A valve 'hunts' when it oscillates rapidly between fully open and fully closed states, often resulting in poor system performance. This phenomenon can occur when a system is not properly balanced or if components are mismatched. An oversized orifice allows too much refrigerant to flow into the evaporator too quickly, which can lead to excessive pressure fluctuations. These rapid changes in pressure can confuse the valve's sensing mechanism, causing it to continuously adjust in an attempt to stabilize, resulting in the 'hunting' behavior.

Understanding the impact of valve and orifice sizes is vital for maintaining efficient system operation. An oversized orifice disrupts the intended refrigerant flow designed for the system, causing instability in pressure and temperature control. This instability is what leads to the hunting condition, emphasizing the importance of selecting appropriately sized components in HVAC systems to ensure smooth, stable operation.