




The Bitmain Antminer S21e XP Hydro 3U is a water-cooled Bitcoin miner of the S21 generation in a rack format with three height units, on the market since 2025. As a SHA-256 machine it is suited to Bitcoin and Bitcoin Cash. Our offer covers the version with 860 TH/s and 13.0 joules per terahash. Cooling is done by water alone, the weight is 42.7 kilograms, and the power connection is three-phase.
The 11,180 watts refer to a water inlet of 35 degrees Celsius; Bitmain does not offer any other level for this housing.
The housing is 900 mm deep, 482.6 mm wide and 130 mm high, which fits a 19-inch rack of matching depth. It ships in a carton of 1,150 × 640 × 260 mm, 48.6 kilograms in total. In operation the 3U reaches 50 dB. It has no pump of its own; the external cooler drives the loop.
16 to 20 litres of coolant per minute have to flow through the machine; the pressure must not exceed 3.5 bar, and the connectors have an outer diameter of 14 millimetres. Antifreeze calls for a pH value of 7.0 to 9.0, pure water 6.5 to 7.5 and deionised water 8.5 to 9.5. At the inlet, 20 to 50 degrees are permitted. If it freezes where the miner is operated, antifreeze must go into the loop without exception.
The 3U draws its power through an LP34 plug at 380 to 415 volts, 50 to 60 hertz and up to 24 amps. Networking is handled by an RJ45 socket rated for 10/100 Mbit. Storage is permitted between minus 20 and 70 degrees; in operation, humidity may reach 10 to 90 percent.
As standard, Bitmain gives a 365-day factory warranty on the machine, counted from the shipping date; our standard price always includes our own warranty.
The predecessor is the Antminer S19 XP Hydro from the S19 generation; the next generation in the same rack format is the Antminer S23 Hydro 3U. The three machines compared:
From the S19 XP Hydro to the S21e XP Hydro 3U, the figure per terahash drops from 20.8 to 13.0 joules, and the S23 Hydro 3U comes to 9.5 joules. As a single machine, the water-cooled S21 generation is available in the Antminer S21 XP Hydro at 12.0 J/TH. The miner comparison sets the daily revenue of the 3U against the other machines we offer.
The S21e XP Hydro 3U is a very good machine in a different form factor from the single hydro units. It packs a great deal of hashrate into very little space and is still extremely efficient.
For the 11,180 watts of the 3U and your electricity price, the Bitcoin mining calculator gives the revenue per day. Every price movement and every change in the Bitcoin network hashrate can shift it; the cockpit shows both, plus the Bitcoin mining pools with share and fees.
When you buy mining hardware via Cryptohall24, you get a guarantee of 12 months In contrast to manufacturer warranties, our warranty only begins when the hardware is sold to our customers and not as soon as it leaves the factory. Since there can often be several months between production and sale in the mining market, our customers often have a longer effective protection than with the pure manufacturer's warranty.
Optionally, the hardware can be added to insured for up to 36 months become.

The process is clear and done in a few steps: you enquire about the device you want, you receive a written quote with the final price from us, and as soon as you accept it, we issue the invoice. After full payment is received, we trigger the order and the hardware is on its way to you.
That way you know where you stand at every point - from quote to delivery, a continuously supported process with a personal contact.
You can pay conveniently by bank transfer in euros, in crypto (Bitcoin or USDC) or in cash against a receipt.
As throughout our business, payment is in advance: we trigger the order as soon as payment has been received in full. That keeps the process clean and predictable for both sides.
Yes, discounts are possible for larger quantities. How large they are depends on several factors - the device, the quantity, the delivery location and the respective procurement conditions.
That's why we state the right price best directly in an individual quote. Just tell us the model and the quantity you want and we'll work it out for you.
On modern ASIC miners the power supply is built firmly into the machine and is therefore always included - it does not have to be bought separately. An external power supply only existed with very old first-generation models.
So you receive a ready-to-run device. Whatever else specifically belongs to the respective product is stated in the product description; in case of doubt we clarify it in the quote.
You can see availability directly on the product; in case of doubt we confirm it in the quote. The majority of our hardware is located in our main warehouse in Hong Kong and is shipped from there directly to your destination.
Individual devices are in stock in Germany (Hamm) - those reach you particularly quickly. We state the concrete delivery date bindingly in the quote, as soon as device and destination are clear.
We deliver worldwide. We handle the shipping and the complete import processing including customs clearance for you - you don't have to deal with it yourself. We state the shipping costs transparently in the quote.
That way the miner arrives ready to use at your place or the desired site. On request we deliver directly to our hosting, then the device goes into operation without a detour.
To operate at home or in your own business you mainly need three things: a suitable power connection (ASIC miners draw several kilowatts continuously, large devices often three-phase power), enough space with ventilation, and a stable internet connection via LAN.
On top of that come noise and waste heat: air-cooled devices are very loud and heat the room noticeably. Anyone who doesn't meet these requirements usually has the miner hosted - then we take care of power, cooling and operation.
Commissioning is straightforward: connect the device, plug it into the network and configure it to your mining pool and wallet. After that the miner runs around the clock.
We don't leave you alone with it - we support you with setting up pool and wallet and the first steps, even without prior experience. Your personal contact is available for questions.
As a German company we offer you 12 months' warranty on your hardware as standard.
Alternatively, you can exclude the warranty in the purchase contract and handle it via the manufacturer's warranty - then the device becomes cheaper. We offer both routes; which one makes sense for you we clarify in the quote.
Yes. You can buy the device from us and have it hosted in the same step - then it runs at a site with low-cost electricity, without noise and heat at your home.
For many this is the most economical way. You can read how hosting works on our hosting page.
We sell our devices to businesses (B2B). A statutory consumer right of withdrawal therefore does not apply in B2B business; in addition, we procure and import the hardware specifically for your order.
So you buy in a targeted and binding way. That's exactly why we calmly clarify the right device for your project before the quote - so you make the right choice from the start. If you have questions before buying, we are always reachable.