I used E+ to model an office building with two chillers. After changing the availability manager schedule from 24/7 to normal office hour, the chillers operating way became weird in summer months: chiller 1 and 2 are on and off a lot during some weekdays. In this model, I made the Chiller Flow Mode "ConstantFlow" and the corresponding chilled water pump "Continuous".
Chiller 1 Plot 1
Chiller 1 Plot 2
Chiller 2 Plot 1
Chiller 2 Plot 2