1、 Daily inspection

1. Appearance and connection inspection
   • Check daily whether the controller casing is intact, without damage or cracks.
   • Confirm that the float, connecting rod, and transmission mechanism are securely connected without any looseness or detachment.
   • Check if the wiring terminals are securely fastened to avoid poor contact caused by vibration.
2. Running status monitoring
   • Observe whether the float moves flexibly without any jamming or abnormal noise.
   • Relay or alarm device action sound, confirm signal output is normal.
   • Record the correspondence between liquid level changes and controller actions to verify logical accuracy.

2、 Cleaning and maintenance

1. Cleaning of floating ball and guide rod
   • Wipe the surface of the float with a soft cloth every month to remove any attached scale, oil, or impurities.
   • Lubricate the guide rod (such as using silicone grease) to reduce frictional resistance.
   • AttentionAvoid using corrosive cleaning agents to prevent damage to the surface of the float or guide rod.
2. Cleaning the interior of the container
   • Regularly clean the sediment or impurities inside the liquid level measuring container to prevent the float from getting stuck.
   • For viscous liquid containers, it is necessary to increase the cleaning frequency to avoid the failure of the floating ball caused by the adhesion of the medium.

3、 Mechanical component maintenance

1. Float and connecting rod inspection
   • Check the floating ball quarterly for deformation, cracking, or magnetic weakening (magnetic levitation ball type).
   • Confirm that the connecting rod is not bent, broken, or worn, and if necessary, straighten or replace it.
   • For the side mounted controller, check the gap between the float and the guide rod to ensure smooth operation.
2. Lubrication of transmission mechanism
   • Lubricate the transmission components such as gears and bearings of mechanical controllers every six months.
   • Avoid excessive lubrication that may cause oil stains to enter the electrical components and cause short circuits.

4、 Electrical system inspection

1. Wiring and insulation testing
   • Check the wiring terminals for oxidation every six months, sand them with sandpaper, and tighten them again.
   • Use a megohmmeter to test the insulation resistance of the controller, ensuring it is greater than 1M Ω (safety standard).
   • Check if the grounding wire is reliably connected to prevent the risk of electrical leakage.
2. Signal output verification
   • Verify the accuracy of relay contact action by simulating liquid level changes.
   • For 4-20mA output models, use a calibrator to detect signal linearity, and adjust if the deviation exceeds ± 1%.

5、 Regular calibration

1. Liquid level calibration
   • Perform full-scale calibration of the controller annually and compare the measured values using standard level gauges.
   • Adjust the float position or calibrate the potentiometer (if any) to ensure that the liquid level display error is ≤ ± 5mm.
2. Alarm point testing
   • Simulate high/low liquid level alarm conditions and verify whether the sound and light alarm device is triggered in a timely manner.
   • For remote monitoring systems, check whether the signal transmission is stable, without packet loss or delay.

6、 Antifreeze and anti-corrosion treatment

1. Low temperature environment protection
   • In cold regions, install insulation sleeves on controllers installed outdoors to prevent floating balls from freezing.
   • Choose low-temperature resistant materials (such as stainless steel floating balls) to avoid brittle cracking of ordinary materials.
2. Corrosion medium protection
   • For strong acid and alkali environments, anti-corrosion floating balls (such as PTFE coating) and 316L stainless steel guide rods are selected.
   • Regularly check whether the anti-corrosion coating is intact, and repair any local damages in a timely manner.

Common faults and solutions