Mokon Troubleshooting Guide Model 311 Process pump will not start Process pump shuts down during operation Pump seal leak Tank overflows or will not fill on systems with autofill option (water makeup valve) Chiller not running System unplugged/power off Improper power source wiring Blown fuse at power supply Low voltage Overload on pump/motor starter Inadequate flow of process fluid Flow switch Chiller shut down Overload on pump/motor starter Blown fuse at power supply Entrapped air in process loop System run dry Temperature run below 20 F with standard seal Debris in fluid loop Float switch for auto fill is stuck Solenoid diaphragm will not seat Start chiller Plug system in/turn power on Check wiring (electrical schematics) and correct Identify open fuse and replace. Check for ground/shorted. Measure incoming voltage. If too low, correct. Press reset button on Overload to reset. Inspect process and process lines for blockage. If blocked, correct. Inspect/clean or replace as needed Check section for possible causes and corrective measures Press reset button on Overload to reset. Replace seal order EDPM seal if running below 20 F Add filtration Inspect. If stuck, clean/replace. 1
Discharge pressure will not build up System does not reach and/or hold temperature Variance in temperature readings Leaking water around the motor shaft Slow response after changing temperature setting Incorrect pump rotation Entrapped air Faulty Pressure gauges Cooling solenoid valve or pressure regulator Heater burn out Heater contactor Loose electrical connections Faulty Thermocouple or RTD Plugged flow paths, inadequate circulation through process and connecting lines Faulty thermometers Leaking Pump seal Heater burn out Heater contactor Sticking Cooling solenoid valve Faulty thermocouple or RTD Reverse phase to incoming power Press purge button. Run system with temperature setting at its lowest setting. Clean or replace valve(s) Tune as required. Refer to controller section in manual. determine correct sizing Tighten connection or replace broken wires Inspect. If plugged, dislodge. determine proper sizing. Tune as required. Refer to controller section in manual for proper procedure. Replace pump seal determine proper sizing Clean or replace valve as required 2
Fluctuating temperature readings from controller Noisy pump Faulty thermocouple or RTD System at end of long feeder line Entrapped air Cooling solenoid valve or pressure regulator Incorrect pump rotation Tune as required. Refer to controller section in manual for proper procedure. Install another source line Press purge button Clean or replace valve(s) Check and correct pump rotation Compressor will not start or shuts down with supply pump running Scroll compressor rotating in the wrong direction Low or high refrigerant pressure Compressor shut down due to thermal protection Inadequate flow of process fluid Freezestat/Fluid is exceeding the low temperature limit Low water flow through the condenser Water regulating valve Switch any two incoming power connections to correct phase issue Let cool, restart and verify amp draw. Consult a qualified refrigeration technician. Inspect process and lines for blockage. Clear blockage if necessary. Make sure all process valves are open. Flow restrictions in process loop, partially plugged evaporator, running below 25% of the chillers rated capacity. Verify condenser supply water flow rate is as stated in manual 3
high refrigerant pressure (water-cooled systems) Condenser supply water lines too small Insufficient water pressure drop across condenser due to plugged or fouled condenser tubes Condenser supply water temperature too high (above 85 F/29 C) Replace lines with insulated hose or pipe of equal diameter as the port (refer to table in manual) Find colder source of water Dirty condenser coils Inspect/clean high refrigerant pressure (air-cooled systems) low refrigerant pressure freezestat Inadequate water flow Fan not rotating Fan rotation High ambient air temperature Refrigeration loop overcharged Inadequate air flow Low refrigerant charge Low head pressure Restriction to refrigerant flow in refrigerant loop Ambient air temperature too cold (air-cooled) Condenser cooling water temperature too low Air in process loop Water/glycol solution foaming Attempting to operate below setting (45 F/7 C) Defective freezestat Low water flow Low water flow causing icing in condenser Requirement is 3 GPM/Ton at 85 F or 1.5 GPM/Ton at 60 F Blown control fuse Verify fan is rotating (counter clockwise) Review chiller location. See manual for installation guidelines. Requirement is 1000 CFM/Ton. Keep inlet of condenser clear. Find warmer source of air Find warmer source of water Purge refer to start up procedures in manual Add a defoaming agent Standard operating range is 50-65 F Increase water flow/remove restrictions 4
Hot gas bypass valve stuck open Chiller does not keep up with load System does not come down to set point temperature Condenser tubes limed over/blocked Poor condensing Over condensing Chiller not started correctly (before heat generating process) Scroll compressor rotating in the wrong direction Chiller undersized for load Lack of refrigerant Dryer clogged Too large process load Evaporator freezing Restrictive process or process connections Faulty Thermocouple or RTD Chiller should be the first piece of machinery started in the process Switch any two incoming power connections to correct phase issue Consult Mokon application engineer for assistance with determining proper size chiller Remove restrictions Inspect/replace component 5