Core issue: The medium-pressure UV disinfection equipment automatically shuts down after more than one month of operation, and repeats the cycle upon restart, with water temperature stabilized at approximately 20°C, severely affecting sterilization efficiency and system stability.

I. Probability ranking of fault causes (from highest to lowest)

1. Ballast (Power/Drive Box) Overheat Protection

Even with normal water temperature, the electrical box may still overheat, triggering the ballast's built-in temperature protection: rising temperature during operation → automatic shutdown if overheating → restart after cooling → shutdown again if overheating occurs.

Diagnostic indicator: Upon power-off, the power box/cabinet housing exhibits significant thermal expansion.

countermeasure ：

• Check if the ballast's cooling fan is running, dusted up, or has damaged blades;

• Ensure the ventilation openings of the power cabinet are not blocked to maintain air circulation;

• Monitor ambient temperature; if it exceeds 40°C, improve ventilation or implement cooling measures.

• If the fan operates normally but still overheats, it may indicate aging internal components (e.g., capacitors or IGBT modules) in the ballast, requiring replacement.

2. Aging of UV lamps, triggering abnormal current/voltage protection

The lifespan of medium-pressure mercury lamps is typically shorter than that of low-pressure mercury lamps. After lamp aging, the starting current increases, and the operating temperature rises, further leading to current exceeding the limit and triggering the ballast's overcurrent protection. Additionally, tube aging causes the lamp voltage to rise, which may also exceed the output range of the ballast, thereby activating the overvoltage protection.

Decision feature:

• The light is dim and reddish when turned on (normally it should be bright white);

• The use time is close to or beyond the life cycle.

Solution: Directly replace with a medium-pressure UV lamp of the same model. The key materials of LIGHTBEST medium-pressure UV lamps, such as glass tubes and electrodes, are all imported with high quality, coupled with strict process control, resulting in a longer lamp lifespan and more stable UV output compared to those from low quality UV lamps manufacturers.

3. Poor contact of socket/wiring

Vibration, high temperature, or oxidation may cause poor contact between the lamp base or terminal block, manifesting as: heating during operation leads to contact disconnection → lamp extinguishment; after cooling, contact resumes → restart and lamp illumination, with repeated cycles.

countermeasure ：

• Inspect the ceramic lamp bases at both ends of the tube for blackening, loosening, or carbon buildup;

• Re-tighten all terminal connections between the ballast, lamp tube, and power supply;

• Replace the lamp socket with a new one if it is worn out or damaged.

4. Leakage Protection/Lines Issues

Moisture or water ingress in the lamp tube, cable, or lamp chamber reduces insulation, triggering the leakage protection device. This manifests as a sudden power outage during operation, with temporary restoration after reboot.

countermeasure ：

• Inspect the lamp chamber for water ingress and the lamp surface for condensation;

• Use a multimeter to measure the insulation resistance of the lamp and cable, which should normally be>2MΩ.

• If insulation is inadequate, perform drying treatment or replace the damaged component.

II. On-site Quick Assessment Mnemonic (1-minute positioning)

· The power cabinet overheats after shutdown → Ballast overheating/fan failure

· Reddish coloration and reduced brightness of the lamp tube → Lamp aging or over life

· Occasional flicker followed by extinction → Poor contact of the socket

· Restart takes a few minutes → Ballast thermal protection (requires cooling before resuming)

III. CONCLUSION AND FURTHER RECOMMENDATIONS

Based on the fault symptoms (normal water temperature, extinguishing after operation, or failure to start/restart), the most probable causes are poor heat dissipation of the ballast, fan malfunction, or ballast aging, followed by lamp aging (replaced when reaching its service life).

Learn about field usage:

1. Does the ballast housing overheat after being turned off?

2. Total lamp running hours?

3. Can it be restarted immediately after being turned off, or after a few minutes?

This enables more precise fault diagnosis and resolution. For further inquiries, please visit our Lightbest official websites at www.light-best.com and www.bestuvlamp.com, or contact us through our official WeChat account.