My robotic pool cleaner won't sink and stays at the surface
Home Nura guide — category: Robotic Pool Cleaners
Diagnosis
This symptom isn't trivial, but in most cases you can fix it without calling in a pro. Work through the steps below in order and stop as soon as the problem clears up.
What to do
1. Unplug it and let it cool. 2. Inspect the parts you can reach. 3. Follow the manufacturer's procedure (owner's manual or official website). 4. If the fix means taking the unit apart, stop and contact customer support so you don't put the warranty at risk.
Repair or replace?
If the problem is still there after these checks and the appliance is out of warranty, weigh the repair estimate against the cost of a new model.
If you're replacing it
Robotic Pool Cleaners: the picks from our buying guide
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Best overall
Dolphin S300i
Cleans the floor, walls and waterline in pools up to 40 ft (12 m) long with no battery to run down, and its fine or ultra-fine filter lifts out from the top.
Photo: © Maytronics
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Best value
Dolphin E35i
Most of what the S300i offers (40 ft pools, waterline, MyDolphin Plus app), plus a caddy cart and an ultra-fine filter in the box.
Photo: © Maytronics (Dolphin)
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Best cordless
Beatbot AquaSense 2 Pro
Fully cordless, it also skims the surface, covers up to 3,850 sq ft (360 m²) and is rated for up to 5 hours on the floor and walls.
Photo: © Beatbot
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Other common problems in this category
These issues affect the same type of appliance — each one comes with a diagnosis and the steps to take.
- Robotic Pool CleanersThe impeller on my robotic pool cleaner is clogged with leaves
- Robotic Pool CleanersThe cord on my robotic pool cleaner tangles every cycle
- Robotic Pool CleanersMy robotic pool cleaner floats up and won't stay on the pool floor
- Robotic Pool CleanersThe filter on my robotic pool cleaner clogs less than 10 minutes into a cycle
Frequently asked questions
Check the manufacturer's warranty first: how long it lasts and what it covers vary by brand and model, so read the terms for yours and keep your proof of purchase. If you bought it new in the EU, a two-year legal guarantee also applies (Directive (EU) 2019/771), covering defects present at delivery, whenever they first show up.
If you're still within the seller's return window, a return or exchange is usually the fastest fix. After that, go through the manufacturer's support team: it handles warranty claims and can often repair the unit even after the warranty has run out. Either way, keep your proof of purchase.
Our public methodology lowers the Nura Score /10 of any model in our Robotic Pool Cleaners guide whose recurring failures show up in owner reviews. A model that breaks down too often never makes it to the top, whatever the brand.
Generally, yes, if you stick to routine maintenance: cleaning, replacing a gasket, recalibrating. Irreversible changes to the hardware are what can cause problems, so read your warranty terms before you open anything up. Anything the manufacturer's manual walks you through is the safe zone.
Your proof of purchase, the exact model name and a record of the symptom: photos, a short video, the sound it makes and any error code. Note when the problem started and what you've already tried. With all that in hand, support can pin down the problem much faster.