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Solar pump seal leak leading to motor breakdown
Hey folks - Thank you for providing this forum.
I am assisting a permaculture farm in southern Arizona that irrigates its crops using a submersible pump in a deep (350'), six-inch diameter well. In 2020, they went from a grid-powered pump to a solar powered one (Sunpump) that does not include a battery bank, so it only pumps when the solar panels are producing energy. Previous pumps stayed operational for several decades each. This solar pump has failed three times in four years, each during the summer months when we were pumping at a lower rate due to the lower efficiency of the solar panels in summer temps. Each time, the manufacturer replaced the motor without providing any insight into what might be causing this problem.
I recently sat down with Sunpumps and they told me that the cause of these breakdowns was the same each time - the shaft seal overheats, causing leaks that then damage the motor. They said that the seals are rated for 100 d F. They are suggesting that the pump itself is not malfunctioning, but that the integrity of the well walls may be in question, obstructing water flow that prevents proper cooling of the system. They suggested that we move the pump up or down 20 feet to see if it changes anything.
I've checked all the other parameters related to the sizing of the pump - the total dynamic head, pump placement (200') wrt the well depth and static/pumping water levels, etc. All of that looks like it is in order. And from what I've read, pump seals can be temperamental. I've thought about having my client get a video inspection of the well, but am on the fence with that given that they've never had these issues before this pump. Essentially, I'm trying to figure out if we got a lemon of a pump or if we really do have deeper issues with the integrity of the well. I have also seen one or two suggestions on reddit that direct solar-to-pump systems may have their own unique challenges, but it doesn't seem like any of those problems would include seal leakage.
So, with that said, I'm wondering (1) does anyone here have experience with Sunpumps for deep submersibles? If so, can you give me any insight into how you experienced their products or customer service? It seems odd to me that we are just now learning the core issue after four years, and it doesn't give me a lot of confidence in their interest in customer service. (2) Does anyone have any experience with perforations in the well casing and how to tell if that is actually happening? (3) Has anyone used video well inspections for problems like this? If so, did you find it useful or worth the money? Can you suggest any other assessment options? (3) Is there any chance that this problem is related to the direct solar part of the system?
I appreciate any insights that anyone here would care to share.
Thanks,
Clarissa
I am assisting a permaculture farm in southern Arizona that irrigates its crops using a submersible pump in a deep (350'), six-inch diameter well. In 2020, they went from a grid-powered pump to a solar powered one (Sunpump) that does not include a battery bank, so it only pumps when the solar panels are producing energy. Previous pumps stayed operational for several decades each. This solar pump has failed three times in four years, each during the summer months when we were pumping at a lower rate due to the lower efficiency of the solar panels in summer temps. Each time, the manufacturer replaced the motor without providing any insight into what might be causing this problem.
I recently sat down with Sunpumps and they told me that the cause of these breakdowns was the same each time - the shaft seal overheats, causing leaks that then damage the motor. They said that the seals are rated for 100 d F. They are suggesting that the pump itself is not malfunctioning, but that the integrity of the well walls may be in question, obstructing water flow that prevents proper cooling of the system. They suggested that we move the pump up or down 20 feet to see if it changes anything.
I've checked all the other parameters related to the sizing of the pump - the total dynamic head, pump placement (200') wrt the well depth and static/pumping water levels, etc. All of that looks like it is in order. And from what I've read, pump seals can be temperamental. I've thought about having my client get a video inspection of the well, but am on the fence with that given that they've never had these issues before this pump. Essentially, I'm trying to figure out if we got a lemon of a pump or if we really do have deeper issues with the integrity of the well. I have also seen one or two suggestions on reddit that direct solar-to-pump systems may have their own unique challenges, but it doesn't seem like any of those problems would include seal leakage.
So, with that said, I'm wondering (1) does anyone here have experience with Sunpumps for deep submersibles? If so, can you give me any insight into how you experienced their products or customer service? It seems odd to me that we are just now learning the core issue after four years, and it doesn't give me a lot of confidence in their interest in customer service. (2) Does anyone have any experience with perforations in the well casing and how to tell if that is actually happening? (3) Has anyone used video well inspections for problems like this? If so, did you find it useful or worth the money? Can you suggest any other assessment options? (3) Is there any chance that this problem is related to the direct solar part of the system?
I appreciate any insights that anyone here would care to share.
Thanks,
Clarissa
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