Clean the cooling tower sumps and condenser pump strainers if you're having flow issues. If your 19XR uses pressure transducers to measure water flow, blow out the pipes on those in case debris is clogging them. The transducers can also go bad, sometimes intermittently.
Building Physics Rule #1: Hot flows to cold.
Building Physics Rule #2: Higher air pressure moves toward lower air pressure
Building Physics Rule #3: Higher moisture concentration moves toward lower moisture concentration.