Waterflows is always the first order of business. Condensor coil clenliness if air cooled. Alot of times its not the chiller it's the ancilary equipment, tower fans off, clogged strainers, dirty coils, etc.
Your poor planning does not constitute an emergency on my part!!!!
Abs is right. Think simple, think flow. Without flow or lack of flow, work is not being performed adequately. Don't let it overwhelm you, just because it is a chiller system. Look at things abs described first. Good luck.
"Excellence is the gradual result of always striving to do better"
I can't imagine being on duty and running a chiller call without ever having worked on one before. Is there anyone else on duty with you that you can call for help? Maybe a buddy in the HVAC field that can help you out?