Bitmain Antminer S21 Hyd. official reference

Official exact hydro reference: Bitmain documents the Antminer S21 Hyd. at 335 TH/s, 5,360 W typical wall power at 35°C inlet water, and 16 J/TH. Actual hashrate is ±3%; wall power and efficiency fluctuate within ±5%.

Three-phase electrical gate

The official input is 380–415 V AC three phase, 50–60 Hz, with 12 A maximum current. A manufacturer note also states 10 A per wire; this reference preserves the published 12 A maximum rather than silently resolving that wording conflict. Do not transfer 200–240 V air-miner assumptions.

Exact coolant-loop requirements

The official modes use inlet-water setpoints of 35°C for NEM, 45°C for HEM1, and 50°C for HEM2. Required flow is 8–10 L/min, pressure is no more than 3.5 bar, and the connection is DN10. The specification lists pure or deionized water with pH 8.5–9.5.

Never energize the server dry. Validate three-phase protection, grounding, isolation, circulation, heat rejection, filtration, water quality, leak detection, and emergency controls before operation.

Physical and environmental reference

The server is 339 × 163 × 207 mm and 12.3 kg net. Packaged dimensions are 570 × 316 × 430 mm and gross weight is 13.6 kg. Network access is RJ45 Ethernet. Storage is −20–70°C and relative humidity is 10–90% non-condensing.

Exact-name boundary

S21 Hyd., S21+ Hyd., S21 XP Hyd., and S21e Hyd. are separate identities. Matching chassis or a 300-series hashrate does not establish the same PSU, coolant chemistry, controller, firmware, recovery method, or facility requirements.

Firmware, recovery, and repair

• Identify the exact label, control board, and installed version.
• The reviewed board-selection matrix does not list S21 models; use only the exact manufacturer support path.
• For no boot, coolant alarms, leakage, corrosion, instability, or electrical and thermal symptoms, request Antminer diagnosis.

Primary source: Bitmain S21 Hyd. specification. Reviewed August 27, 2026.