Maintenance of the solar submersible pump system: panels, inverter, and pump

Last updated: October 18, 2026

Maintenance of a solar submersible pump system focuses on three main parts: the panels (regular cleaning to remove dust and inspection of the casing and cables), the submersible pump inverter (clean ventilation and review of the alarm log), and the pump itself (monitoring its output and current to detect corrosion early). Most major malfunctions begin with small signs that can be observed during routine inspections before the pump stops working in the middle of summer.

Why does the maintenance of a submersible pump system differ from that of a home water system?

With a grid-tied home system, if its output drops, the grid compensates for the difference without the user noticing. However, with a submersible system, any decrease in solar panel output is immediately reflected as a decrease in water supply. Furthermore, submersible systems often operate in harsher environments: open farms exposed to dust and wind, water that may contain sand or salts, and long distances between the panels, the well, and the inverter.

Therefore, submersible pump system maintenance focuses on factors affecting the incoming water, in addition to the general inspection checklist we explained in Solar system maintenance: Periodic checklist.

Maintenance of solar panels and structure on the farm

Cleaning

On farms, dust accumulates quickly, and may be mixed with residue from nearby sprinklers or bird droppings. The frequency of cleaning depends on the location and season: some sites require weekly cleaning during dusty seasons, while others only need cleaning every two weeks or a month. A practical indicator: if you notice the pump starting late in the morning or the flow rate lower than usual in the afternoon, begin by checking the cleanliness of the panels.

Use low-salt water and a soft brush, and avoid cleaning at midday when the panels are very hot. Full details in Cleaning solar panels from dust.

Structure and Foundations

• Check the bolts and nuts, especially after strong winds, and tighten any that are loose.
• Check for any rust at cut points, holes, or galvanizing scratches, and treat them with a zinc-rich coating.
• Make sure that the foundations have not been affected by irrigation water or soil erosion around them.
• Remove weeds and plants growing under or around the panels, as they shade the panels and become a hazard in the summer.

Cables and connectors

Inspect exposed cables for insulation cracks caused by sun exposure, rodent gnawing, or friction against metal edges. Ensure that MC4 connectors are securely fastened and show no signs of blackening or melting, as these indicate excessive heat during connection.

Maintenance of the submersible inverter (solar VFD)

The submersible inverter is responsible for converting the solar panels' electricity into a current suitable for the motor, and for protecting the pump from dry running and inappropriate voltage. Its most important requirements are:

• Clean ventilation: Clean the ventilation openings and fans of dust and insects. An overheated inverter will automatically reduce its power output, causing a decrease in pumping without you knowing why.
• Shade and protection from rain: The inverter should be in a well-ventilated, shaded room or box, not in direct sunlight.
• Alarm log: Review the recorded alarms monthly. For example, a repeated dry run alarm indicates that the well is declining or operating above its productivity. For explanations of common messages, see Common Inverter Alarms.
• Settings: Do not change the inverter settings (minimum frequency, current protection, level sensors) except with the knowledge of the technician who set them, because they are related to the motor specifications.
• Connections within the board: The technician inspects it annually, tightens the cable ends, and ensures the safety of the circuit breakers, lightning protection, and grounding.

How do you know that your plunger pump is starting to weaken?

The pump is buried in the well and you can't see it, but its specifications tell you its condition. For general faults in the rest of the system, refer to [reference/website/etc.]. Common solar system malfunctions and how to detect them. These are the most important signs of a weak pump:

The sign	Possible cause	What are you doing?
Acting less than usual on a sunny day and the panels are clean	Defense corrosion, suction filter blockage, riser pipe leak, or well level drop	Compare with your previous readings and request a technician inspection.
The motor current is higher than usual for the same frequency.	Mechanical friction, sand in the pump, or a problem with the engine.	Stop the repeated starting and request a check before the engine burns out.
Repeated dry start alarm	The water level drops more during pumping than before.	Measure the well level; you may need to reduce the flow or lower the pump.
Sandy or murky water	Problem with the well or filters	Address the cause of the sand buildup, as it accelerates pump wear.
The pump is working but no water is coming out.	Broken drive shaft, pipe separation, or complete blockage	Turn off the power immediately and call a technician.

Record your readings

The simplest maintenance tool is a notebook or chart on your phone where you record, once a month, on a sunny day around noon: the frequency at which the inverter is operating, the motor current, the behavior if you have a meter, and the time it takes for the tank to fill. After a few months, you'll have a reference, and any noticeable change means something needs to be checked. Many submersible inverters display these readings on the screen or in a monitoring app.

The tests performed by the technician

• Measure the insulation resistance of the motor cable and motor with a dedicated device to detect moisture leakage before the motor burns out.
• Measuring the static and dynamic water levels and comparing them to previous readings.
• Pull the pump out when needed to inspect the impellers, filter, drive shaft and non-return valve.

Proposed maintenance schedule for a solar submersible pump system

The following table is a guide and should be modified according to your site conditions and manufacturers' recommendations:

repetition	Tasks	Who does it?
Weekly or according to dust levels	Check the panels and clean them as needed, ensuring the pump is working and the tank is full.	farm owner or worker
monthly	Recording frequency, current, and behavior; reviewing alarms; cleaning the inverter's ventilation openings.	farm owner or worker
Every 3–6 months	Inspecting cables, connectors, and screws; testing the float and level sensor.	Technician or trained worker
annually	Inspecting the inverter board, circuit breakers, and grounding; measuring the motor insulation; measuring the well level.	Specialized technician
When signs of weakness appear	Pump removal, inspection, or maintenance	Technician specializing in towing equipment

Specifically, before the summer season begins, conduct a thorough inspection, because this is the season with the highest water demand and the highest temperature for the inverter and motor.

Common mistakes that shorten the lifespan of the system

• Leaving the panels dirty for weeks and then judging the system to be weak.
• Place the inverter in a metal box under the sun without ventilation.
• The dry-run sensor was disconnected because its alarm was “annoying,” so the pump operated without water.
• Increasing the pump's output above the well's productivity to fill the reservoir faster.
• Postponing pump inspection despite the appearance of sand or high current until the motor burns out.

The simple rule: every noticeable change in system behavior has a cause, and investigating it early is far cheaper than replacing a burnt-out motor or worn-out pump in the middle of the irrigation season. If the farm is far from you, train the worker to perform simple weekly checks and record the readings, and leave the electrical and mechanical work to the qualified technician.

Frequently Asked Questions