Low temperature coolant circulation pumpThe inability to lower the temperature may be caused by various factors such as refrigeration system failure, circulation system problems, environmental or operational factors, abnormal sensors and controls, changes in coolant characteristics, etc. The following are specific reasons and troubleshooting methods:
1、 Refrigeration system malfunction
Leakage or insufficient refrigerant
Phenomenon: The compressor continues to operate but the temperature cannot decrease, or the cooling effect gradually deteriorates.
Reason: Leakage caused by aging refrigerant pipelines, loose joints, or damaged compressor seals.
Troubleshooting: Check the refrigerant pressure gauge. If the pressure is lower than the normal value (usually 0.5-1.5MPa), refrigerant needs to be replenished and leak checked for repair.
The efficiency of the compressor decreases
Phenomenon: The operation time of the compressor is prolonged, but the temperature drops slowly or stagnates.
Reason: Insufficient power due to internal wear of the compressor, insufficient lubricating oil, or aging capacitors.
Troubleshooting: Measure the compressor current. If it is lower than the rated value (such as a 1.5kW compressor rated current of about 3.2A), replace the capacitor or repair the compressor.
Condenser/evaporator blockage
Phenomenon: Uneven frosting on the surface of the condenser, or the outlet temperature of the evaporator is higher than the set value.
Reason: Dust and oil stains block the heat sink, or impurities in the coolant deposit inside the heat exchanger.
Troubleshooting: Use compressed air to blow the condenser fins, or disassemble the evaporator to clean the internal pipes.
2、 Circulation system issues
Insufficient flow of circulating pump
Phenomenon: Slow flow of coolant leads to a decrease in heat transfer efficiency.
Reason: Wear of pump impeller, bending of pipeline or incomplete opening of valve.
Troubleshooting: Check the pressure difference between the inlet and outlet of the pump. If it is lower than 0.1MPa, replace the impeller or adjust the pipeline layout.
Pipeline leakage or air resistance
Phenomenon: System pressure fluctuations or continuous decrease in coolant level.
Reason: Loose pipeline joints, cracked welds, or system failure to exhaust causing air resistance.
Troubleshooting: Use soapy water to detect the leakage point, or open the exhaust valve to discharge the air in the system.
Low efficiency of heat exchanger
Phenomenon: The temperature difference between the inlet and outlet of the coolant is less than 2 ℃, or the temperature of the cooled equipment remains high.
Reason: scaling inside the heat exchanger, low coolant flow rate, or insufficient heat transfer area.
Troubleshooting: Disassemble the heat exchanger for cleaning, or increase the power of the circulation pump to increase the flow rate.
3、 Environmental or operational factors
The ambient temperature is too high
Phenomenon: In summer or high-temperature workshops, the cooling capacity of equipment significantly decreases.
Reason: The heat dissipation of the condenser is limited by the ambient temperature, resulting in a decrease in cooling efficiency.
Solution: Move the equipment to a well ventilated area or add a forced air cooling device.
Excessive load
Phenomenon: The heat generated by the cooled equipment exceeds the cooling capacity of the pump.
Reason: The heating power of the reaction kettle is too high, or multiple devices share a low-temperature pump.
Solution: Reduce heating power or increase the number of low-temperature pumps to share the load.
Operation parameter setting error
Phenomenon: The deviation between the set temperature value and the actual value is too large, or the cycle mode selection is improper.
Reason: The user did not adjust the temperature, flow rate, or circulation method according to the experimental requirements.
Troubleshooting: Check the control panel parameters to ensure that the temperature setting value is reasonable (such as using cascade cooling below -20 ℃).
4、 Abnormal sensor and control
Temperature sensor malfunction
Phenomenon: The displayed temperature does not match the actual temperature (such as displaying -10 ℃ but actually being 0 ℃).
Reason: Sensor aging, position deviation, or poor circuit contact.
Troubleshooting: Use a standard thermometer to calibrate the sensor, or replace the sensor with a new one.
Control system malfunction
Phenomenon: The compressor frequently starts and stops, or the temperature fluctuates by more than ± 2 ℃.
Reason: Improper PID parameter settings, control board malfunction, or unstable power supply.
Troubleshooting: Reset the control system parameters or contact the manufacturer to repair the control board.
5、 Changes in coolant characteristics
Improper concentration of coolant
Phenomenon: The freezing point of the ethylene glycol/water mixture is higher than the set temperature.
Reason: The user did not prepare the coolant in proportion, or long-term use caused changes in concentration.
Solution: Use a refractometer to detect the concentration of the coolant and adjust it to the specified range (e.g. 50% ethylene glycol is required for the -40 ℃ freezing point).
Coolant contamination
Phenomenon: The coolant becomes turbid, has peculiar smell or produces foam.
Reason: Impurities entering the system, microbial growth, or chemical corrosion.
Solution: Replace with brand new coolant and clean the interior of the system.
VILow temperature coolant circulation pumpMaintenance and prevention suggestions
regular maintenance
Clean the condenser fins every 3 months and replace the lubricating oil and dry filter every 6 months.
Perform annual air tightness testing on the system to ensure no leaks.
Operating Specifications
Avoid frequent starting and stopping of equipment to reduce compressor wear.
Drain the coolant during winter shutdown to prevent pipeline freezing and cracking.
Spare parts reserve
Reserve commonly used spare parts (such as sensors, capacitors, refrigerants) to shorten the time for fault repair.