There are two main divisions of solar pumps: submersible and surface. Each of these can be used for different purposes, and therefore come with their own unique set of problems, so here some of the most common problems (and solutions) you may encounter with your new solar pump.
What are some of the most common problems with solar pumps? Solar pump malfunctions include:
- Pumps failing to start/function
- Tilt angle causing inconsistent water flow
- Low water production
- Water running continuously
- Malfunctions with low well sensor
- Damaged pumping mechanism
- Moisture inside/on PV panel
- Hot spots in cells
- Hot cells
Knowing the problem is only half the battle. Continue reading for an in-depth look at each of these common issues and how to fix them!
Types of Solar Pumps and Associated Problems
As described by EL-PRO-CUS:
- Submersible solar pumps: these pumps are capable of lifting water from 650 feet and are
suggested for a depth of approximately 150 feet. These pump water in the day
time (during sunshine, of course), and water is stored in an external tank for
- Main problems: pump malfunctioning or not powering on. Typically, this can be attributed to a failure of the control box or malfunctioning of, or damage to, pressure switch.
- Surface solar pumps: these work for ponds and shallow wells. The maximum recommended
depth of water is 20 feet. These can push water up to 200 feet. They are best
for pulling water from approximately 60 feet.
- Main problems: more vulnerable to environmental damage due to being installed at the surface level, typically use more power than submersibles. These things can result in lower water production and exposure to obstructions to PV panels, resulting in lower energy efficiency.
As they are not installed below the freezing line, these pumps are particularly vulnerable to damage in the pump mechanism or pipes during winter months due to expanding, frozen water.
How Long do Solar Pumps Last?
The average life expectancy of a solar pump is about 20-25 years, with regular maintenance. For instance, panels and the pump need to be cleaned to prevent a build-up of debris, which could contribute to lower water production due to either blockage of the solar panels or congestion of soil particles in the pump.
Although solar panels can be expensive to maintain (at the beginning), they are beneficial in that they allow individuals to be in direct control of their water supply at all times and they’re at their peak production in summer due to frequency and strength of sunlight.
Given their long lifespans, the cost of the solar panel is ultimately less than that of a traditional generator, as they do not need as frequent replacement of parts and constant, intensive upkeep.
Now, this is not to say that your solar pump will never need any upkeep. Few issues come up quite often with solar pump users. Here’s a comprehensive list of the most common problems with solar pumps (and how to fix them).
1. Pump Will Not Start or Function at All
There are several reasons a pump may not start or function at all. The first thing you need to do is figure out exactly what is causing this problem You may be able to repair the solar pump, or call someone in to repair it, but you might also need to replace it.
- Check the voltage of the system: Voltage should be at 10%± motor ratings. Read voltage at pressure switch, control box, and any other components power may be running through.
- Check Pressure Switch: Look for deformed, burned or melted parts or discoloration, namely all black components. Check for sediment/debris in the tube/nipple leading to switch. Check that contact points are being opened and closed accordingly.
- Check Control Panel: Check for apparent defects or simply signs of wear and tear. Look specifically for burnt, loose or melted components.
- Check Splice Connections: Check for any corrosion or obvious damage. Typically, there is a splice connection at the top of the well, between the submersible cable and the UF/THHN.
- Check the Pump and Motor: If none of the above yields results, it may just be time to replace the pump and/or motor.
Although, before you toss it, there are many ways to troubleshoot the pump and motor, so check with the AIM Manual on Submersible Motors first.
2. Tilt Angle Causing Inconsistent Water Flow
If the angle of the solar panel is too steep, not all of the surface area is being used, and therefore not as much energy is taken in. This results in a significantly decreased production level of water.
RPS Solar Pumps offers a graphic explaining the perfect tilt angle for your solar panel based on your location in the United States.
Northern states such as Washington, Montana, and North Dakota are recommended to maintain a fixed Tilt Angle at 37˚, with adjustments for summer angles of 2˚ and winter angles at 41˚.
Southern states, including Arizona, New Mexico, and Texas, are suggested to have fixed Tilt Angles at 30˚, adjusting to 11˚ in summer and 50˚ for winter.
Once you adjust the angle for your proper latitude and time of year, you will see an immediate improvement in the water production of your pump.
3. Low Water Production
Any blockage of light will affect your solar pump’s performance in that it is unable to collect as much sunlight for energy production. Some pumps are so sensitive that even shadows cast in passing by a human will decrease water production.
Microcracks and shattered glass can also seriously affect water production. These issues can arise due to defects in manufacturing, problems in transport or during installation. Although at first, it will only cause a small loss in power, this loss will increase over time and cause you to lose out on a lot of energy, and therefore, water, production.
Check the surroundings of the chosen site. Consider locating your solar pump in an area that has little foot traffic (both animals and humans), to avoid casting shadows, and get rid of any overhanging vegetation that may even completely block some of the cells.
Also, take a look at the height of your pump in the well. If your pump is too high in the well, it will not pull up an adequate amount of water. Lower the pump into the well, and it should return to producing normally.
Lastly, examine your panel closely for cracks or any deformities in the cells.
Some have tried using polyurethane to “paint” over the cracks and re-seal the panel, applying upwards of six coats.
Synergy Power, however, says that such DIY fixes are, in fact, not a good idea as there are many chemical reactions required to properly seal the PV (photovoltaic) panels.
Ultimately, you may have to look into the replacement of the panel, as the expertise and materials required for this replacement are not likely available to the average person.
4. Water Running Continuously
According to Silicon Solar, there may be a break in the line or a check valve in the riser pipe may be open. This can either be between the pump and the building to which the water is being supplied, or in the plumbing of the building.
A few troubleshooting steps to this would be to:
- Keep an eye out in the yard for any puddles. This will be a tell-tale sign of where the leak is occurring.
- Shut off the water in the house and look at the water pressure gauge. If it remains consistent, there is no problem with the check valves and no leaks. If the pressure drops, there is a leak in the line to the house or an issue with the check valve.
If the latter is the case, you will need to contact a professional plumber to help you fix the problem.
Otherwise, check the pressure switch and try to lower the minimum pressure. Make sure to turn off the power before adjusting the pressure switch.
Hunker suggests even considering a smaller well pump if none of the above solve the problem, as seasonal changes can have drastic effects on elements such as the height of the water table.
5. Malfunctions with Low Well Sensor
If the low well sensor is too high in the water, not in the water at all, or not connected to the controller. The sensor will remain on, and the system will not pump water.
This can happen especially often in dry summer seasons, when production is at its peak, meaning the well runs lower much faster.
Check that your sensor is submerged and perform a system reset. Once on again, the system will recognize that the sensor is submerged, shut off the Low Well alert and continue pumping water.
6. Damaged Pumping Mechanism
Helical rotors are particularly prone to this. If the Stator is being operated outside of the water, it can overheat and melt, and not function properly. The build-up of sediment/debris in the well can wear out your Stators even faster. Wear and tear over time will also damage these mechanisms.
You will need to pull up the pump and replace the pumping mechanism. This process only takes about 15 minutes.
RPS Solar Pumps provides an in-depth instructional video on performing tests on their Solar Well Pump Kits and knowing when to replace this mechanism.
7. Moisture Inside, or on, PV Panel
Moisture can enter the panel when the backsheet becomes separated from the back of the panels if the backsheet is cracked or the glass of the panel is cracked.
Moisture inside the solar panel can cause corrosion and decrease performance efficiency over time.
Moisture on the exterior of the panels can reduce efficiency as well, as solar.com notes, because the water vapor and droplets will reflect light away from the panel, reducing the amount of energy it can take in.
Humid weather can contribute to these conditions.
Take a look at the build of your solar panel. Some panels are built with ventilation apertures to allow airflow into the panel to solve the inevitable build-up of condensation within the plate.
North American Clean Energy notes that, for flat-plate collectors, a 50-fold daily air change rate is optimal.
Proper ventilation of your solar panel can work only if it’s secured on the appropriate mounting hardware, as the ventilation apertures are located on the back of the panel for protection from the rain.
For condensation inside the glass, the ventilating/insulating functions of the backsheet and apertures will solve this within an hour.
For wetness on the exterior of the panel, make sure to regularly clean the glass, as water, debris and anything that can reflect light away from or cast a shadow on the panel will significantly reduce energy production.
For panels with moisture damage caused by the separation of the backsheet from the panel, Gold Coast Solar Power Solutions states that these must be replaced, as the integrity of the hardware has been significantly compromised. The same is recommended for the following two common problems.
Civic Solar suggests avoiding panels that use backsheets made of non-UV resistant material, such as polyvinylidene difluoride (PVDF) film. Just behind these are polyethylene terephthalate (PET) backsheets. These backsheets are subject to a significant amount of defects, 60% and 30%, respectively.
Backsheets composed of polyvinyl fluoride (PVF) are recommended as the most reliable material.
8. Hot Spots in Cells (Burn Marks Inside Cell)
This can create a serious fire hazard. There will be holes in the cells, and it can even burn the backsheet of the panel. Hot spots can also cause the glass of the solar panel to shatter across the entire panel or in a localized region.
This can be caused by poor soldering or poor joints during manufacturing.
This instance is considered a failure of the solar panel, and it needs to be replaced. See the previous section for information on choosing reliable material for backseet to avoid this problem in the future.
9. Hot Cells (Outside of Cell is Burned)
There is resistance in energy production in the cell, and so the cell overheats and burns around the edges.
Instead of passing power through the cell, the cell somehow creates a bit of resistance in energy production, and so overheats. Power from the rest of the panel can feed into this and burn the cell even more.
This instance is considered a failure of the solar panel and it needs to be replaced. See section, “Moisture Inside, or on, PV Panel,” for information on choosing reliable material for backsheet to avoid this problem in the future.
Maintenance and Care for Solar Pumps
Being armed with the knowledge of the 9 most common problems with solar pumps and their fixes will go a long way for you, but installing and maintaining your solar pump properly will go a lot further.
What you can do to prevent these major problems from happening is making the best choices before the installation of your solar pump.
You can avoid unnecessary moisture condensation in the panel by not only choosing the best material recommended for backsheets, but also ensuring that your backsheet isn’t directly exposed to the sun (this is where tilt angle comes into play).
For problems with the pumps themselves, as you saw, these issues can often be identified and solved on your own. More often than not, the problem lies in a pump that was set too high in the well or some sort of obstruction blocking the intake of solar rays.
When troubleshooting these problems, it is recommended to start at the surface level first.
Meaning, check that the solar panel and connections are working properly before moving lower to the pump or controller. As these parts are not subject to environmental exposure as the solar panel is, unless there is a manufacturer defect or a mistake was made during installation, you should not see any problems with the functioning pump components.
Thankfully, solar pumps do not require a lot of maintenance.
- Every few years, the solar panel needs to be cleaned with soap and water.
- Once or twice a year, perform a routine inspection of water flow. This will immediately tell you of issues with low water flow or inconsistent water flow.
That’s it! Solar pumps do not take much maintenance at all, and as you can see above, troubleshooting is just as user-friendly.
Ultimately, Is a Solar Pump Worth the Trouble?
The uses of solar pumps for access to clean water for underprivileged communities and large-scale use for livestock owners are now recognized by the Food and Agriculture Organization of the United Nations and USDA.
Unfortunately, some of the major problems you may see with your panel will ultimately need to be replaced or looked at by a professional.
If so many things can go wrong, and further, so many things that would ultimately need replacement by a professional, why bother?
- Solar well pumps are significantly more energy-efficient than alternative power sources for pumping.
- They are virtually maintenance-free
- Solar pumps, both surface and submersible, are long-lasting.
- They can be installed almost anywhere, whether you live in the suburbs or a rural area.
- No ongoing costs
Problems that can arise with solar well pumps are almost negligible when looking at the advantages, durability, and low-maintenance traits of this system.