With regard to their application in refrigeration systems, which of the following statements about flow switches is false?
a. They are used on chilled water systems
b. They are used as shutdowns or permissives when flow is insufficient
c. They are operated by the force exerted on a flexible vane immersed in the fluid flowing in the line
d. They can only be used to regulate liquid flow, not air flow
e. They can be used to close flow indicator circuits
Answer: D