Reason: It may be cool water not enough; or cool load low; or failure occurred at throttle orifice; or heat transfer at heat transfer tube of evaporator bad for the pollution like furring; or lack of refrigerant.
Solution: Check the cool water circuit and refill the cool water to rated volume; or check the rated temperature at auto on/off device; or check if expand throttle is blocked; or clean the heat transfer tube; or fill the refrigerant to needed volume.
Reason: It may be cooling water not enough; or capacity of cooling tower reduced; or temperature of cool water too high; or cooling capacity too high to increase the load at condenser; or non condensed gas exist; or heat transfer at condensing tube bad for the pollution like furring.
Solution: Check the cool water circuit and adjust it to rated current flow; or check cooling tower and expand throttle etc. to lower (or rise) the temperature of cool water to rated temperature as soon as possible; or get rid of non condensed gas; or clean the tube.
Reason: It may be oil filter blocked; or oil pressure adjusting valve (gate gurgle valve) opened too wide; or outlet oil at oil pump decreased; or bearing abrades; or failure occurred at oil pressure meter (or sensor); or too many refrigerant mixed into lubricating oil (oil pressure is too low for oil bubbles when starting).
Solution: Change the core of oil filter; or tighten the oil pressure adjusting valve so that the oil pressure rise to rated pressure; or disassembly to check; or change the bearing; or check oil pressure meter, reset the pressure sensor and change it when necessary; or do apply the oil heater when cooler stops to maintain rated oil temperature (check if wire of oil heater is breaking, and if the set temperature for oil heater to heat is correct).
Reason: It may be cool water not enough; or cool load low
Solution: Check the cool water circuit and refill cool water to rated volume; or wait for cool load rise.
Reason: It may be oil pump broken; or resistance at oil circuit too great.
Solution: Disassembly the oil pump to check; or check the oil circuit system like oil filter and other components, change them when necessary.
Reason: It may be cooling capacity of oil cooler lowered; or refrigerant supply for cooling oil cooler not enough for refrigerant filtering net is blocked; or bearing abrades.
Solution: Adjust oil temperature adjusting valve; or clean refrigerant filtering net; or disassembly to repair or change bearing.
Reason: It may be cooling water not enough; or failure at differential meter
Solution: Check cool water pump and cool water circuit and adjust to normal flow volume; or check and repair differential meter.
Reason: It may be power phase voltage unbalance; or voltage drop at power cord large; or operating with ultra-low head; or refrigerant supply for cooling main motor not enough for refrigerant filtering net is blocked.
Solution: Take measures to make power phase voltage balance; or take measures to lower voltage drop at power circuit; or clean the refrigerant filter net.