What are the disadvantages of butterfly valves?

Restricting flow is one of the biggest downsides. The valve disc is always present in the fluid flow path, which results in a constant pressure loss. This can present problems in systems where a low resistance is needed. Although High Performance Butterfly Valves and Double Offset Butterfly Valve designs reduce this problem, it is still more significant compared to ball valves.

Sealing limitations​ are yet another worry. Resilient-seated valves, which are the most common type, may not provide for a truly bubble-tight shutoff for long durations, particularly in abrasive or high temperature applications. While SS Butterfly Valve models and Keystone Butterfly Valves have greater life expectancy, it is possible for elastomeric seats to degrade over time and cause leakage. This may mean more maintenance or replacement at a shorter interval, particularly for critical applications.

Complexity and cost of actuation​ are other negatives. The addition of an Electric Valve Actuator or a Butterfly Valve Actuator increases the cost and also requires electrical infrastructure. Motorized Butterfly Valve units require periodic checking of the actuator, wiring, and control. In very cold, hot, humid or wet environment, where actuators can deteriorate in service, due to rust, burning/moisture contact or power failure and cause them to stop working.

Precision limits in throttling operation is also a limitation. Although butterfly valves do control flow, they are not as accurate as globe valves in that regard. Disc "racing" can produce turbulence and cavitation, especially in Lug Type Butterfly Valve and Wafer Type Butterfly Valve installed in high pressure systems.

You should also think about material compatibility. A stainless butterfly valve is best for corrosive environment, but the low grade types may be rust or chemical attack. In addition, the Butterfly Check Valve variations are also subject to erosion due to constant fluttering in unstable flow conditions.

Finally, there are installation limitations. These two styles have very specific orientation requirements and aren't designed to be used as shut-off valves in certain pipeline arrangements without additional support. Flanged Butterfly Valve types are more robust and rigid, thus more costly to install but require more substantial support.