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Two months ago, I built a water well in my basement to collect the water coming into it. A submersible pump with an integrated float switch should then pump the water out via a hose. Unfortunately, things turned out quite differently.
Submersible pump broken after a month?
During my routine checks, I regularly checked the water level in the pump well. The submersible pump worked safely and reliably for a month.
But now I noticed that the pump no longer turns off automatically. Furthermore, the pump rattles and makes noises as if it is about to explode. Obviously, I made a big mistake when creating the sump.
The damp cellar is located under the actual cellar. The house was built in 1900. The exterior walls were drained and yet this basement was always damp as the water entered from below after heavy rains.
To collect this water, a month ago I built a sump in the corner of the basement. The water can collect in the drainage pipe and is automatically pumped out by a pump.
Currently, I direct the water outside to the garden via a ¾ inch garden hose.
- Die robuste Tauchpumpe für gründliche Entwässerungsaufgaben von Regenfässern, Brunnen und Pools
- Integrierter Schwimmerschalter mit Umschalter für Automatik- oder Dauerbetrieb zur Niveauregulierung des Wasserstands
- Besonders flachsaugend bis 2mm Wasserstand zur nahezu restlosen Entleerung. Max. Wassertemperatur: 35 °C
- Stabiler Tragegriff mit integrierter Kabelaufwicklung am Kunststoffgehäuse für die schnelle Einsatzbereitschaft
- Universalanschluss für flexible Anschlussmöglichkeiten
The last days there were again very productive and long-lasting snow and rainfalls. So the water is again pushing into the basement from below.
This morning I noticed that the pump no longer switches off after it has pumped the water out of the shaft. Also, the pump rattles very loudly. Something is not right there.
I got the pump out of the sump and disassembled it on my workbench. It was there that the problem became apparent.
A video says more than a thousand words
By the way, you can find many more videos on this important topic in my playlist on the project Drying out the basement. If you want to see more of me and my projects, feel free to check out my YouTube channel.
The pump sucks in stones
Even though I placed the pump in the well on a brick, it sucked in the small rocks I used as drainage and filter from the substrate. These little stones got caught in the pump and caused some damage there.
The pump sucks the water from below through an opening with a rather coarse strainer. So there was no real protection against foreign bodies.
The small stones then got stuck under the impeller and on the sides. The impeller in the pump was scraped. Some corners are also broken off. Inside the housing, the pressure was then so great that parts of the plastic casing broke off.
This is, of course, very annoying. I simply underestimated the suction power of the pump. Although the pump was 10 cm above the ground, the suction was so strong that it sucked in the small stones.
If you want to replicate this project, be sure to think about adding a filter between the pump and the bottom. Or put the pump more than 10cm above the ground.
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Repairing the submersible pump with tape and sealant
I have tried to repair my pump. To do this, I fixed the broken parts with tape.
Behind the tape I put a special adhesive. This hardens completely and is waterproof. I sealed the hole in the sheathing the same way.
The repaired areas didn’t really look pretty, but my construction was fit for purpose and worked.
The water runs back
Before I put the pump back in the shaft, I solved a second problem which I became aware of through this incident.
I had chosen this pump model because it can easily pump the water up the 5 to 6 meters. Unfortunately, the pump does not have a check valve. As soon as the pump switches off, the water flows out of the hose back into the shaft.
I originally assumed that only the water from the riser would flow back and the rest would then drain to the outside.
Unfortunately, this is not the case. The pump is well below the surface. As soon as the pressure decreases, all the water runs back down into the shaft due to the negative pressure from the hose. That would be 25 meters instead of the calculated 5 meters.
Retrofit check valve for the pump
I decided to use a small check valve. The valve has ¾ inch female threads on both sides and is made of brass. The plate and the spring inside are made of stainless steel.
The gasket is made of NBR. This is a synthetic rubber with chemical resistance and high abrasion resistance. So this valve should last a long time.
To be able to screw on the adapter for the garden hose I still need a double nipple with ¾ inch external thread on both sides.
- Zuverlässiges Abpumpen von bis zu 14.000 Liter klares bis leicht verschmutztes Wasser pro Stunde
- Automatische Entlüftung ab einem Wasserstand von 7 mm nimmt die Pumpe den Betrieb im Manuell-Modus auf
- Robuster und einfach anzubringender Edelstahlvorfilter schützt die Pumpe vor zu starker Verschmutzung und verhindert damit eine Verstopfung des Pumpenlaufrads
- Anwendungsgebiete: Wasserschäden im Haus und im Keller, Abpumpen von Wasser aus Pools und Installation im Drainage-Schacht
- Lieferumfang: Entwässerungspumpe mit komfortablem Tragegriff, Schlauchanschlussstück, Edelstahl-Vorfilter, keramische Gleitringdichtung
Are there any alternatives to my sump pump?
The old pump has been running for a week now without any problems. I built a second brick underneath and additionally placed the pump in a wastebasket with a fine grid structure.
Due to these modifications, no more stones are sucked in – however, the residual water level now remains somewhat higher. This is not yet a perfect solution. I’ll have to think of something better.
But maybe you have a good tip for me?
Drop me a line in the comments!
In the meantime, I have replaced the pump with an INOX drainage pump from Kärcher. This pump had already proven to be powerful and reliable when I was working on the pool.
In the pump shaft, this pump now does the work – safely and effectively.