Ensure the chiller vessel is properly configured for normal use. This includes checking the wiring is undamaged and secured in place, making sure the power source is active and none of the circuit breakers have tripped. Reset the circuit breakers if the latter issue is present.
Check for any vibration coming from the pipes. This could indicate the supports which hold the pipes in place are loose or, worse, the pipes are damaged. These problems will have to be fixed or the issue will deteriorate further.
Visually inspect the base of the chiller for any leaks. This could indicate loose seals allowing vital fluids to seep away. Have this issue fixed by an expert before you try and use the unit again.
Touch the liquid lines to ascertain whether they are overheating. If they are very hot, it indicates a blockage of the coolant; replace the line filter drier cartridges by pulling the old cartridge out of the unit and inserting a new one.