New submersible pump defective – draining the cellar
Two months ago I built a sump pit with a sump pump in my cellar to collect the water seeping into it and further dry out my cellar.
A submersible pump with an integrated float switch should then pump the water out via a hose.
Unfortunately, things turned out quite differently. The new submersible pump in the pump sump was defective after just a few weeks. Read this article to find out why the pump was destroyed and how the draining process continued.
During my regular routine checks on and in the house, I always checked the function of the pump and the water level in the pump shaft. The submersible pump worked safely and reliably for over a month.
However, my Home Assistant system recently informed me of unexpectedly high power consumption. The cause was the new pump, which no longer switched off automatically. It also made rattling noises that gave the impression that it was about to malfunction.
I had obviously made a serious mistake when creating the pump sump.
Submersible pump broken after one month
The affected cellar, damp and located below the actual cellar, is in a house that was built in 1900. Despite the exterior walls being drained, this cellar always remained damp, as water penetrated from below during heavy rainfall.
To collect this water, I built a sump pump in a corner of the cellar a month ago. The water was able to collect in a drainage pipe and was then pumped out automatically.
The matching article can be found here: Draining the cellar – pump sump | Build your own soakaway
I directed the pumped-out water into the garden using a ¾-inch garden hose. We recently had another heavy and prolonged downpour of snow and rain, which caused the water to push into the cellar again from below.
This morning I noticed that the pump wouldn’t switch off after pumping out the water and was rattling very loudly.
There was obviously a fault. I then removed the pump from the sump and dismantled it on my workbench, where the problem finally became apparent.
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- Einfach zu transportieren ist die Pumpe durch den stabilen und ergonomischen Tragegriff und integrierter Aufhängeöse für die schnelle Einsatzbereitschaft.
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- Das schlanke Design in Verbindung mit dem integrierten Aquasensor und dem Pumpenauslass an der Oberseite ermöglicht auch den Einsatz in sehr engen Bereichen wie z.B Drainagen oder Schächten.
Video: Pump in soakaway defective
I recorded the repair of the defective pump and the further optimizations to my pump shaft in a video and published it on my YouTube channel.
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.
Zuletzt aktualisiert am 15. November 2024 um 08:17 . Ich weise darauf hin, dass sich hier angezeigte Preise inzwischen geändert haben können. Alle Angaben ohne Gewähr. (*) Bei den verwendeten Produktlinks handelt es sich um Affiliate Links. Ich bin nicht der Verkäufer des Produktes. Als Amazon-Partner verdiene ich an qualifizierten Verkäufen. Dein Preis ändert sich jedoch nicht.
The pump sucks in stones
Although I had placed the pump in the shaft on a brick to achieve a certain height above the ground, it still sucked in small stones that I had used as drainage and filter material.
These stones got caught in the pump and caused considerable damage.
The water was sucked in by the pump from below via an opening with a rather coarse sieve, which offered no real protection against the ingress of foreign bodies.
The small stones collected under the impeller and on the side walls of the pump, damaging the impeller and breaking off some of the corners.
The resulting pressure inside the housing was so great that parts of the plastic casing broke off. This was of course very annoying and showed that I had considerably underestimated the suction capacity of the pump.
Despite the elevation of 10 cm above the ground, the suction was strong enough to suck in the small stones.
For anyone planning a similar project, I strongly recommend placing a filter between the pump and the floor or placing the pump even higher, i.e. more than 10 cm above the floor.
- 1m KG Steigrohr DN315 oder DN400
- VARIANTE 1 - DN315 Nennweite: DN315 Länge: 100 cm Material: PVC (Polyvinylchlorid)
- VARIANTE 2 - DN400 Nennweite: DN400 Länge: 100 cm Material: PVC (Polyvinylchlorid)
Repairing the submersible pump with tape and sealant
I have tried to repair my pump. To do this, I first fixed the broken parts with adhesive tape.
Behind the adhesive tape I filled in a special adhesive that hardens completely and is waterproof. I sealed the hole in the sheathing in the same way.
Although the repaired areas were not visually appealing, my design proved to be fit for purpose and worked perfectly.
- Wagner GREEN MS-Polymerkleber ist ein einkomponentiger Unterwasserkleber für die Anwendung im Pool¹, Schwimmbad, Gartenteich, Aquarien. Unterwasser Verklebung, Reparaturen und Abdichtung auf fast allen Untergründen. Kann direkt mit Wasser in Kontakt kommen, bzw. unter Wasser verarbeitet werden
- Reparatur Dichtmasse der neuesten Generation auf Polymer-Basis, klebt auf nassen Untergründen³, sehr hohe Klebekraft, größe Dehnfähigkeitm gleichbleibend elastisch, gute UV- und Witterungsbeständigkeit, Überstreichbar, Lösemittel- & isocyanatfrei, sofort schlagregenfest
- Reparatur Kleber für Notreparaturen: Löcher abdichten im Schwimmbad¹, Schwimm- und Koi Teichen. Undichte Stellen an Dachrinnen, Wintergärten und Aussenanlagen sofort abdichten. Klebt und dichtet Aquarien, Terrarien und Teichfolien
- Spezial Kleber zur Verklebung und Abdichtung von: Glas, Naturstein, Holz, Stahl, Kupfer, Aluminium, Kunststoffe (nicht rückfettende), PVC, EPDM und Kautschukfolien, Teichfolien, GFK uvm. - Erstellung von Klebedichtungen unterschiedlichster Materialien, mit einander und untereinander
- Erneuern von Fliesen und Fugen auch unter Wasser¹ - Abdichten im Feuchtraum- und Sanitär-bereich² - Ausbessern von Undichtigkeiten im Dachbereich³
The water runs back
Before I put the pump back in the shaft, I solved another problem that I had become aware of as a result of this incident.
I originally opted for this pump model because it can easily pump the water up the 5 to 6 meters.
However, the pump lacked a non-return valve, which meant that as soon as the pump switched off, the water flowed out of the hose and back into the sump.
I had originally assumed that only the water from the riser would flow back and the rest would drain to the outside. However, this turned out to be a misjudgment.
As the pump is well below the surface, when the pressure dropped, all the water ran out of the hose back into the sump due to the resulting negative pressure. This meant that the water flowed back 25 meters instead of the calculated 5 meters.
- Massives und langlebiges Rückschlagventil aus Messing geeignet für Wasserversorgungs-, Heizungs-, Klima- und Druckluftanlagen
- Gewinde: 3/4" (24,12 mm / DN 20) Innengewinde
- Material: Körper aus Messing, Teller und Feder aus Edelstahl, Dichtung aus NBR
- Montage: in der senkrechten, waagerechten und schrägen Lage montierbar
- Betriebstemperatur: -20°C bis 100°C / Gewindeanschlüsse: ISO228 / Nenndruck: 25 bar (PN 25)
Retrofit check valve for the pump
I decided on a small non-return valve, which has ¾ inch internal threads on both sides and is made of brass. Inside, the valve has a stainless steel plate and spring.
The seal is made of NBR, a synthetic rubber that is characterized by its chemical resistance and high abrasion resistance. This promised a long service life for the valve.
To screw on the adapter for the garden hose, I also needed a double nipple with a ¾ inch external thread on both sides.
A non-return valve is an important component in pump systems as it prevents the backflow of water. It ensures that the pumped-out water does not flow back into the pump sump when the pump switches off.
The valve opens when water flows in the desired direction and closes automatically as soon as the flow stops or reverses. This effectively keeps the pump sump dry and reduces the load on the pump.
Risks when installing the non-return valve
However, there are a few risks to consider when installing a non-return valve.
A key point is the position of the hose that drains the water. If this hose is located in an area that is not frost-proof, there is a risk that it will freeze in winter.
A frozen hose can block the water and cause a backflow, which increases the pressure on the pump and can ultimately lead to damage.
In addition, a non-return valve can become blocked by deposits and dirt over time. This requires regular maintenance and cleaning to ensure proper functioning.
Another risk is the incorrect installation of the valve. If it is not installed correctly, it can lead to leaks or reduced efficiency of the pump system.
It is therefore crucial to check the non-return valve regularly and ensure that the drain hose is frost-proof to ensure proper operation of the system.
- Starke Performance: Die Kärcher Schmutzwasser-Tauchpumpe SP 16.000 Flood Box bewältigt bis zu 16.000 Liter Wasser pro Stunde – auch verunreinigtes Wasser mit Schmutzpartikeln von bis zu 20 mm Größe
- Für den schnellen Einsatz: Im Flutkorb lassen sich die Pumpe und der 10-m-Gewebeschlauch mit werkzeugloser Befestigung aufbewahren. Der Korb kann zudem als Vorfilter verwendet werden
- Höhenverstellbarer Schwimmerschalter: Der höhenverstellbare Schwimmer lässt sich an der Pumpe fixieren, damit die Pumpe im automatischen Betrieb früher startet und flacher abpumpt
- Gut geschützt: Dank der keramischen Gleitringdichtung und der Ölkammer ist die Tauchpumpe SP 16.000 Flood Box besonders langlebig und kann problemlos im Dauerbetrieb eingesetzt werden
- Lieferumfang: Im Lieferumfang ist die Kärcher SP 16.000 Flood Box Schmutzwasser-Tauchpumpe enthalten sowie ein Quick Connect-Schlauchanschluss und ein G 1- und G 1 1/2-Anschlussgewinde
Optimize pump protection in the soakaway
The old pump worked without any problems for the following week after my adjustments. I placed an additional brick under the pump and also placed it in a wastepaper basket with a fine grid structure.
These modifications prevented stones from being sucked in, but the residual water level remained somewhat higher.
Alternatives for avoiding particles in the pump
To prevent coarse particles and small stones from being sucked into the pump, there were various approaches that I considered.
In addition to using the metal mesh wastepaper basket, I thought about other ideas to extend the life of the pump and increase its efficiency, researching other options and talking to other homeowners.
The recommendations for protecting the pump from stones and coarse dirt were ultimately always the same:
- Install pre-filter: An additional pre-filter could have been installed upstream of the pump to trap larger particles. These filters were specially developed for pump systems and could be easily cleaned or replaced.
- Fine-mesh protective baskets: In addition to the waste paper basket, a fine-mesh protective basket could have been placed directly over the inlet of the pump. These baskets were often made of stainless steel and offered an additional protective layer against particles.
- Regular cleaning of the pump s ump: Regular cleaning of the pump sump could have removed deposits and dirt before they entered the pump. This would have reduced the risk of clogging and extended the service life of the pump.
- HEPA filters: HEPA filters, which float in the water and catch particles before they reach the pump shaft, could also have been a useful addition.
However, all four options for protecting my pump proved to be useless for me as the pump sucked in the water over the entire floor area and regular cleaning of the pump sump would blow up my schedule.
Another idea was to place the pump in a pre-filter bag. These pre-filters are normally used in industrial vacuum cleaners to reduce the load on the actual filter.
Unfortunately, I couldn’t find a model in the right size and was also worried that the fabric would clog up too quickly with the suspended particles in the water.
The idea of placing the pump in a metal mesh wastepaper basket, on the other hand, proved to be quite effective. The fine mesh prevented larger particles from entering the pump, while the water continued to flow out without any problems.
However, this slightly increased the residual water level in the pump sump, which could be undesirable in some cases. Nevertheless, this method offered good protection and was relatively easy to implement.
I look forward to receiving further tips and suggestions to optimize the system even further. Your comments and experiences are very welcome!
- Dekorativ: Der runde Papierkorb fügt sich mit seiner schönen und zugleich unaufdringlichen Optik bestens in Ihre Einrichtung ein - Dekoartikel in schicker Mesh-Optik - Schwarze Variante
- Vielfältige Nutzung: Praktisch für die Mülltrennung in der Küche - Zusammengeknüllte Blätter und Werbeprospekte im Wohn- oder Arbeitszimmer schnell entsorgen - Drahtkorb als Begleiter im Büro
- Schneller Überblick: Der Abfallkorb besteht aus einem Drahtgeflecht - Der Papiereimer ist offen - Aufgrund der Gitter-Struktur sehen Sie sofort, wie voll oder leer der Papiersammler ist
- Starke Details: Dank der abgerundeten Kanten ist der Papiersammler auch fürs Kinderzimmer geeignet - 3 dezente Noppen sorgen für festen Stand und schonen Fliesen sowie Bodenbeläge
- Basics des runden Mülleimers: Der Abfalleimer fasst ca. 19 Liter - Der obere Durchmesser des Abfallkorbes beträgt ca. 30, der untere ca. 24 cm - Der leichte Drahteimer wiegt nur ca. 600 g
New INOX pump for the soakaway
In the meantime, I replaced the old pump with an INOX drainage pump from Kärcher. This had already proved to be powerful and reliable during my work on the pool. This new pump now performs its work safely and effectively in the pump shaft.
The Kärcher dewatering pump SP 6 Flat Inox is a high-performance device that has been specially developed for demanding dewatering tasks.
This pump is characterized by a maximum flow rate of up to 14,000 liters per hour and can pump water down to a minimum residual water height of just 1 mm, making it particularly effective in flooded areas.
The maximum immersion depth is 7 meters and the maximum delivery head is 9 meters, which underlines its versatility.
Thanks to its robust stainless steel housing and ceramic mechanical seal, the SP 6 Flat Inox offers increased durability and reliability.
The pump also has an automatic float switch, which enables safe and energy-saving operation by automatically switching the pump on and off depending on the water level.
Kärcher INOX pump
The technical specifications of the new pump are impressive:
- Delivery rate: up to 14,000 liters per hour
- Minimum residual water level: 1 mm
- Maximum immersion depth: 7 meters
- Maximum delivery head: 9 meters
- Housing material: Stainless steel
- Seal: Ceramic mechanical seal
- Float switch: Automatic
Kärcher, founded in 1935, has made a name for itself worldwide as a leading supplier of efficient, resource-saving cleaning systems.
Kärcher offers a wide range of products, from high-pressure cleaners and vacuum cleaners to various pump solutions that are suitable for both private and professional use.
- 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
Summary and conclusion
Two months ago, I built a soakaway with a pump sump in my basement to collect any water seeping in and keep the basement dry. A submersible pump with a float switch was supposed to pump the water outside, but after a few weeks the pump was defective.
Routine checks showed high power consumption and noise, which indicated a malfunction.
The cellar is located in a house built in 1900 and remains damp despite the exterior walls having been drained. Heavy rainfall led to renewed water problems. I placed the pump in a metal mesh basket to prevent stones from being sucked in, but this increased the residual water level slightly.
In the meantime, I replaced the old pump with a Kärcher SP 6 Flat Inox. This pump is powerful, has a flow rate of up to 14,000 liters per hour and pumps water down to a minimum residual water height of 1 mm.
It is made of robust stainless steel, has a ceramic mechanical seal and an automatic float switch.
To keep particles and stones out, I considered various approaches such as pre-filters, fine-mesh protective baskets, regular cleaning and HEPA filters. The metal mesh basket proved to be effective and easy to implement.
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