STULZ CyberAir 3PRO
One model name spans DX, dual-fluid, and chilled water; the suffix decides 2027 EPA exposure
STULZ CyberAir 3PRO is one of 4 CRAC and CRAH units tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.
Room and in-row air cooling runs out of headroom as rack density rises; above roughly 40 kW per cabinet the load is picked up by liquid cooling, usually retrofitted into halls that keep their CRAC units for the remaining air-cooled rows. The catalogue entries closest to that decision are ZutaCore HyperCool Two-Phase Immersion and GRC ICEtank Immersion Cooling.
STULZ CyberAir 3PRO specs, capacity in kW and tons, DX refrigerant options, GWP values, and the 2027 EPA and EU F-Gas deadlines for used equipment buyers.
CyberAir 3PRO is a family name, not a single SKU. Model codes combine an air-conduction prefix, a size class, and a cooling-system suffix, and that suffix is the whole story: A/AS, G, and GE/GES all carry a compressor and refrigerant circuit, while CW and CW2 are pure chilled-water coils with none at all. ACW and GCW sit in between, pairing a chilled-water primary path with a DX backup circuit in one cabinet. The nameplate alone settles nothing until that suffix is read. DX capacity spans 22-150 kW (6.3-42.7 tons) across all five DX variants; CW spans 22-260 kW (6.3-73.9 tons) on STULZ's own product page. Both sides use scroll compressors, either fixed-speed on/off units or STULZ's continuously modulated "EC compressor," with EER around 4.3-5.5 kW/kW. Five refrigerants populate the DX lineup and split on the 2027 deadline. R-407C, R-410A and R-134a all exceed EPA's 700 GWP ceiling for new CRAC manufacture; R-513A (GWP 630) already clears it on the on/off-compressor ASD/ASU/ALD/ALU series, and R-454C (GWP 146) clears it comfortably on the newer GE4(S) range. The EU's stricter F-Gas Regulation 2024/573 caps new data-center AC at GWP 150 on the same date, a ceiling R-513A fails despite passing EPA's, leaving only R-454C compliant on both. STULZ is the one name in this category never absorbed into a larger industrial group, founded in Hamburg in 1947 and still family-held, and it shipped EC fans as standard on its CyberAir 1 in 2003. A same-vintage Liebert unit was more likely built with belt-driven fans; Vertiv still sells a paid retrofit kit to convert those units today.
Why it matters
The model-code suffix, not the product name, decides whether a unit has refrigerant exposure at all and, on the DX side, whether it already clears EPA's 700 GWP limit taking effect January 1, 2027. R-513A clears that US limit today; the EU's stricter 150 GWP F-Gas ceiling on the same date fails R-513A and passes only R-454C, so a unit compliant in one market can fail the other.
Who buys it
Data center and colocation operators sourcing room-perimeter CRAC or CRAH capacity, telecom and edge site owners standardizing on one European brand across DX and chilled-water rooms, and buyers working European used-equipment channels where STULZ resale activity concentrates. A buyer must confirm the suffix on the physical nameplate before pricing, since "CyberAir 3PRO" alone names neither a compressor nor a refrigerant.
Role in the data center
Room-perimeter cooling for a data hall, server room, or telecom space, sized well above in-row or rack-level units and below large central chiller-plant equipment. The DX variants (A/AS, G, GE/GES, ACW, GCW) serve rooms without or supplementing a chilled-water plant; the CW/CW2 variants serve rooms already fed by a central chiller.
Key specifications
| Cooling capacity, DX line (all variants) | 22-150 kW (6.3-42.7 tons) |
|---|---|
| Cooling capacity, CW line (product-page figure) | 22-260 kW (6.3-73.9 tons) |
| Cooling capacity, GE4(S) low-GWP DX | 24-71 kW (6.8-20.2 tons) |
| Airflow, DX line | 4,000-32,000 m3/h |
| Airflow, CW line | 7,500-46,200 m3/h |
| Electrical supply, standard (EU/international) | 400 (380-415) / 3-phase+N+PE / 50 V, Hz |
| Electrical supply, alternate options | 230V/3Ph/50Hz; 208V/3Ph/60Hz; 460V/3Ph/60Hz V, Hz |
| Dimensions, smallest cabinet (size 1) | 950 (W) x 1,980 (H) x 890 (D) mm |
| Dimensions, largest cabinet (size 7) | 3,110-3,350 (W) x 2,495-2,915 (H) x 980-1,040 (D) mm |
| Operating weight, ASD 231 A (DX, air-cooled) | 376 kg |
| Operating weight, ASU 640 CW (chilled water) | 373 kg |
| Sound pressure level range | 46-58.5 dB(A) |
| Filter class | ISO 16890 (ISO Coarse 80% to ePM10 70%) rating |
| EER, compressor mode (headline range) | 4.3-5.5 kW/kW |
| EER, ASD 231 A at 53C condensing temp (unit example) | 2.96 kW/kW |
| Standards compliance (DX) | EN 378, EN ISO 12100, EC Machinery Directive 2006/42/EC, RoHS 2011/65/EU - |
Technical summary
DX capacity: 22-150 kW (6.3-42.7 tons) CW capacity: 22-260 kW (6.3-73.9 tons), OEM sources disagree up to 272.8 kW GE4(S) low-GWP DX capacity: 24-71 kW (6.8-20.2 tons) Compressor: scroll, on/off or continuously modulated "EC compressor" EER, compressor mode: 4.3-5.5 kW/kW Refrigerants: R-407C, R-410A, R-134a, R-513A, R-454C Electrical supply: 400V (380-415V) / 3-phase+N+PE / 50 Hz standard Fan technology: RadiCal EC fans, latest generation EPA CRAC-subsector GWP limit: 700, effective January 1, 2027 EU F-Gas 2024/573 self-contained data-center AC limit: GWP 150, same date
Configurations and options
Air-conduction prefix (ASD downflow, ASU upflow, ASR raised-floor with external fan box) combines with the cooling-system suffix and a numeric size class to form the full model code. On/off fixed-speed compressors run on the ASD/ASU and ALD/ALU series; STULZ's continuously modulated "EC compressor" runs on AS and GES systems. Alternate voltages (230V/3Ph/50Hz, 208V/3Ph/60Hz, 460V/3Ph/60Hz) are available against the 400V/50Hz standard configuration.
Compatibility and dependencies
A buyer should not assume "CyberAir" branding alone identifies this model: STULZ separately sells CyberAir 2 (the direct predecessor), CyberAir Mini/Mini CW, CyberOne (a distinct EC-DX line), CyberRow, CyberPack, Ceilair, and EVE (an Italian-subsidiary line), and a listing that hedges between "CyberAir" and one of these names should not be priced as CyberAir 3PRO without a confirmed ASD/ASU/ASR/ACW/GCW/CW/CW2 model code on the nameplate.
Pricing and availability
Comparable secondary-market band: 75–700 $ per ton. Trend: flat
Lifecycle and maintenance
No STULZ document publishes a numeric service-life, MTBF, or overhaul interval for CyberAir 3PRO. The continuity case is concrete, not asserted: STULZ is the one major name in this category never absorbed into a larger industrial group, founded in Hamburg in 1947 and still family-held, and it shipped EC fans as standard on its CyberAir 1 as early as 2003, so its EC-fan and driver-board failure history run longer than any competitor's. Vertiv's own Liebert lineup shows the contrast: legacy DS, DH, and Deluxe System/3 units shipped with belt-driven AC fans, and Vertiv still sells a paid EC Fan Upgrade Service to retrofit them today. A 15-year-old STULZ unit's parts and control-board sourcing run through the same unbroken entity that built it, not a post-acquisition successor brand.
Thermal and emissions profile
Five refrigerants span STULZ's CyberAir 3PRO DX lineup: R-407C (GWP 1,774), R-410A (2,088), and R-134a (1,430) all exceed EPA's 700 GWP ceiling for new CRAC manufacture after January 1, 2027; R-513A (630, on the on/off-compressor ASD, ASU, ALD and ALU series) already clears it; R-454C (146, on the GE and GES "GE4(S)" range) clears it comfortably. The EU's F-Gas Regulation 2024/573 is stricter on the same date, capping new self-contained data-center AC at GWP 150 - R-513A fails that ceiling despite passing EPA's, leaving R-454C as the only refrigerant compliant in both markets. CW and CW2 units carry no refrigerant circuit at all; their exposure sits upstream at the chiller plant.
Common failure points
- Scroll compressor — rising amp draw at constant load, reduced sensible capacity, high-head-pressure trips
- Refrigerant circuit leak points — repeated small refrigerant top-offs, declining subcooling on successive service visits
- EC fan driver board — fan fails to modulate, runs fixed-speed or not at all despite an intact motor
- E2 controller firmware and comms card — BMS integration errors, lost setpoint history, obsolete Modbus or BACnet card
- Condenser and evaporator coil fouling — falling sensible capacity and rising head pressure at unchanged load over time
- Humidifier and reheat subsystem — subsystem bypassed or physically disconnected, canister corrosion, no humidity control
- Backup DX circuit on ACW or GCW units — backup circuit sits idle for years while the primary chilled-water path carries the load
Inspection checklist
Nameplate refrigerant charge — confirm R-407C, R-410A, R-134a, R-513A, or R-454C — the five options span GWP 146 to 2,088 and only two clear EPA's 700 GWP limit Model code suffix — confirm A, AS, G, GE, GES, ACW, or GCW versus CW or CW2 — a CW/CW2 nameplate carries zero refrigerant exposure, an ACW/GCW nameplate hides a backup DX circuit Compressor run-hours — pull the on-board E2 controller counter reading, not a verbal estimate, before rigging Refrigerant leak-rate history — request 3 years of service tickets with logged superheat and subcooling readings, not a single spot check Superheat at the evaporator outlet — verify it falls within 8-12F of design at the last recorded service — a wide deviation signals a metering-device or charge problem Subcooling at the condenser outlet — check against the unit's design target on the startup sheet — low subcooling with normal superheat points to undercharge Scroll compressor amp draw — review the trend over the last 12 months — a rise of more than 10% at constant load indicates wear before audible failure EC fan driver-board revision and firmware — confirm STULZ or a distributor still stocks the exact board fitted, since driver electronics are a documented CRAC failure point E2 controller firmware and comms protocol — confirm Modbus or BACnet compatibility with the buyer's BMS before purchase, not after installation Condenser and evaporator coil fin condition — inspect 100% of the coil face for fouling or damage, not one corner Belt-drive versus EC fan — a genuine CyberAir 3PRO should carry EC fans as standard — a belt-driven fan on a unit labeled 3PRO is a mismatch red flag Humidifier and reheat subsystem — confirm whether it is still connected and functional or was bypassed, a common condition on aging units EPA Section 608 refrigerant recovery — confirm a licensed technician performs recovery before deinstallation and logs recovered weight against the original charge Water-side connections and pressure rating on CW, CW2, ACW, or GCW units — pressure-test to the stated maximum, 16 bar on the sourced ASU 640 CW example Cabinet weight versus rigging plan — confirm actual operating weight, 373-376 kg on the two sourced unit examples, against floor-load and lift-plan assumptions
Regional notes
STULZ's own catalog splits by regulator, not just by refrigerant. Against EPA's 700 GWP limit on CRAC-subsector manufacture from January 1, 2027, R-513A (GWP 630) already clears the bar on the on/off-compressor ASD, ASU, ALD and ALU series. Against the EU's F-Gas Regulation 2024/573, which caps new self-contained data-center AC at GWP 150 on the same date, that same R-513A fails by a wide margin and only R-454C (GWP 146) passes. A buyer sourcing across both markets, or moving a European-built unit to a US site or the reverse, cannot assume one region's compliant refrigerant satisfies the other. Electrical supply follows the same regional split: 400V/3-phase+N+PE/50Hz is standard on international documentation, with 230V/3Ph/50Hz, 208V/3Ph/60Hz and 460V/3Ph/60Hz offered as alternates for other grids.