How does a flow-check piston type metering device work? What ...

[joblessjake]

How does a flow-check piston type metering device work?
 
  What will be an ideal response?

Question 2

Why do coil manufacturers specify both wet and dry coil static pressure drops?
 
  What will be an ideal response?

[kusterl]

Answer to Question 1

It checks in the forward direction, forcing the refrigerant to pass through a small hole. In the reverse direction it opens like a check valve.

Answer to Question 2

The Dry coil reading represents the pressure drop through the coil if no water is condensing on it. The wet coil pressure drop represents the pressure drop through the coil if it is condensing water. The water takes up space between the fins, increasing the pressure drop through the coil.

[joblessjake]

Thanks

[kusterl]

Welcome