If the average power output (or performance tables) is increasing after cleaning, but the water pressure of the cleaning equipment is low, it indicates that the cleaning is insufficient or improper, which can lead to both underperformance and long-term module damage. 

Here is a breakdown of why this happens and the risks involved:

Why Low Pressure & Increasing Averages Indicate Problems

Ineffective Cleaning: Low-pressure water struggles to dislodge caked-on dirt, bird droppings, or stubborn grime. This means the panel is not reaching its full generation potential, even if it seems slightly better than before.

Mineral Deposition: Low pressure often means you are forced to spend more time scrubbing, which, if using non-RO (reverse osmosis) water, leads to water drying on the panel and leaving mineral residue (scaling). This residue reduces sunlight transmittance, permanently reducing efficiency.

Abrasive Risk: If the pressure is too low to remove dirt, operators often resort to harder manual scrubbing. This can cause micro-scratches on the glass, destroying the anti-reflective coating (ARC), which causes permanent power loss. 

Risks of Low Pressure/Improper Cleaning

Module Damage (Micro-cracks): Excessive manual scrubbing to compensate for low water pressure can lead to micro-cracks on the cells.

Thermal Shock: Using cold water on hot panels (often done when pressure is low and cleaning takes longer, extending into warmer hours) causes rapid expansion and contraction, which can lead to glass cracks.

Hot Spots: Incomplete cleaning leaves behind stubborn patches, creating shaded areas. These shaded cells act as resistors, creating "hot spots" that can damage the module, reduce its lifespan, and cause permanent degradation. 

Recommended Action

Check Water Quality: Ensure you are using water (TDS < 500 mg/L) to prevent mineral deposits.

Optimize Pressure: Ensure the pressure is low-to-medium (not exceeding 35 bar at the nozzle) but sufficient for effective cleaning without needing harsh scrubbing.

Use Proper Tools: Use soft brushes or sponges to prevent scratching the glass.

Timing: Clean early in the morning to avoid thermal shock.