I'm having difficulty making the zone relative humidity control properly with a chilled water system. I'll admit that I have a lot less experience with chilled water coils than with DX... Background:

• The chiller is providing water at the correct setpoint temperature
• Airflow is as specified
• Zone temperature is at the proper setpoint
• I tested 3 scenarios as shown below and hope that I've condesned the main details so you can comment without an IDF.

The short version of this question is this: Why is humidity NOT controlled (very well) with the simplest approach (:SingleZone:Humidity:Maximum)? That works very well for DX, so it's surprising and confusing (not to mention annoying) that chilled water coils don't work as well.