What are the common malfunctions of well‑type level gauges, and how can they be resolved?

　　 Manhole level gauge What are the common malfunctions and their solutions?

　　Well‑level gauges are widely used in industrial process control, petroleum refining, pharmaceuticals, food processing, water treatment, gas stations, grinding machinery, valve‑opening control, and other fields, where they monitor, alarm, and regulate physical parameters such as liquid level, temperature, density, and interface conditions.

　　What are the common malfunctions of well‑type level gauges, and how can they be resolved?

　　1. The level gauge reading remains unchanged.

　　Faults: transmitter loss, power supply failure, float jamming, pressure valve blockage, etc.

　　Solution:

　　(1) Check whether the connection wires of the manhole level gauge are loose; if so, tighten them immediately. Verify that the supply voltage is normal and that the card is outputting power, then inspect the measurement card’s fuse for damage. If the fuse is blown, replace it. If the fuse is intact, replace the card.

　　(2) Clean, unclog, and replace the pressure valve. If there is dirt inside the float and cylinder, clean it promptly.

　　(3) Verify that the level transmitter and the signal generator’s power supply are functioning properly; if no output signal is present, replace them.

　　2. The liquid level display differs from that of the host computer.

　　Fault: The loose component of the level transmitter is damaged or partially displaced.

　　Solution:

　　(1) Check the local liquid level display. If it is normal, inspect the transmitter to determine whether an output signal is present. Otherwise, the transmitter must be replaced.

　　(2) When using a level gauge, if the aforementioned issues arise, they can be addressed by following the methods described above. To minimize malfunctions, ensure proper operation of the level gauge and perform routine maintenance as specified.

　　What is the cleaning of a manhole level gauge?

　　1. When cleaning the well‑level gauge, first loosen the nut on the iron pipe at the gauge’s location, then carefully remove the gauge; clear any debris adhering to the gauge, such as aquatic plants and plankton.

　　2. When cleaning the pressure‑sensing port of the level gauge, inject trichloroethylene or alcohol into the port to a depth of about half its height and let it soak for 5 minutes. Then gently shake the gauge and repeat this process several times until the port is thoroughly clean. Do not use any tools to clean the pressure port, as this may damage the pressure‑sensitive diaphragm of the sensing element.

　　3. When cleaning the transmitter’s pressure port and pressure fitting, do not use brushes with excessive hardness or metal tools to avoid damaging the sensing element and the threads of the pressure port.

　　4. Cleaning Manhole level gauge Afterwards, gently place the level gauge back into the iron pipe, ensuring that the lower portion of the pipe is properly positioned, then reinstall the nut in its original location. Following disassembly and cleaning, reinstallation may alter the installation depth. Therefore, it is necessary to compare the water level readings at the same gate position and recalibrate the secondary water meter’s measured values to ensure the accuracy of the sampled data.