Table of Contents
Motivair Liquid Cooled Doors, also known as rear door heat exchangers (RDHXs), are liquid-to-air heat exchanger cooling systems that remove high levels of heat generated by today’s servers, mass storage systems, and core networking hardware.
It is mounted directly to the rear panel of HPE racks. RDHXs are compatible with 42U or 48U racks across a range of IT capacities under specified load and site conditions.
RDHXs are designed to complement new or existing data centers by enabling computing-power growth without adding to the heat load in the data center.
Overview
Airflow through the RDHX fully supports industry-standard front-to-back cooling designs and standard server dimensions. Hot air exiting the rear of the servers passes through the RDHX coils, where it is cooled. Depending on the data center room’s dew point, the RDHX can connect directly to the facility water supply or to a cooling distribution unit (CDU). Top-feed and bottom-feed options are supported. Mural graphics on the doors are also supported. The RDHX can also be deployed with direct liquid cooling (DLC) to increase the percentage of heat captured by water and meet room-neutral requirements.
Standard Features
Key Features
General Solution
- – Liquid to air heat exchanger cooling system attached to back of a standard IT rack
- – Hot air exhaust from the server moves through cooling coils to remove the heat
Cooling Capacity (kW per rack)*
- – M8: 5–17 kW
- – M12: 14–35 kW
- – M14: 35–55 kW
- – M16: 55–75 kW (only available in 48U × 800 mm)
*See the RDHX Site Planning Guide for additional information and specifications.
Water
- – Accommodates facility water temperatures 2°C (4°F) above the maximum anticipated dew point.
- – Accommodates water pressure between 25 and 100 psi (172–689 kPa).
- – For water temperatures at or below the dew point, a cooling distribution unit (CDU) is required to create a warmer secondary water loop that supplies the doors.
Power
- – Supports 208 V, 230 V, or 277 V single-phase input power.
Flexibility
- – HPE Apollo 42U or 48U racks support shipment of fully integrated rack solutions through HPE Factory Express or partner rack integration because the racks are delivered on shock pallets.
- – Underfloor and overhead plumbing capabilities
- – Full service offering available, including planning, deployment, and maintenance.
Agency Certifications
- – ETL, CSA, and CE certified.
Configuration Information
Each Motivair Door SKU includes
| |
| Description | SKU |
| HPE M12 42U 600mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4M97A |
| HPE M14 42U 600mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4M98A |
| HPE M12 42U 600mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4M99A |
| HPE M14 42U 600mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N00A |
| HPE M14 42U 600mm G2 Rack 260-290V Top Feed Rear Door Heat Exchanger | S4N01A |
| HPE M14 42U 600mm G2 Rack 260-290V Bottom Feed Rear Door Heat Exchanger | S4N02A |
| HPE M12 42U 800mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4N03A |
| HPE M14 42U 800mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4N04A |
| HPE M12 42U 800mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N05A |
| HPE M14 42U 800mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N06A |
| HPE M14 42U 800mm G2 Rack 260-290V Top Feed Rear Door Heat Exchanger | S4N07A |
| HPE M14 42U 800mm G2 Rack 260-290V Bottom Feed Rear Door Heat Exchanger | S4N08A |
| HPE M12 48U 600mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4N09A |
| HPE M14 48U 600mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4N10A |
| HPE M12 48U 600mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N11A |
| HPE M14 48U 600mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N12A |
| HPE M14 48U 600mm G2 Rack 260-290V Top Feed Rear Door Heat Exchanger | S4N13A |
| HPE M14 48U 600mm G2 Rack 260-290V Bottom Feed Rear Door Heat Exchanger | S4N14A |
| HPE M12 48U 800mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4N15A |
| HPE M14 48U 800mm G2 Rack 208-230V Top Feed Rear Door Heat Exchanger | S4N16A |
| HPE M12 48U 800mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N17A |
| HPE M14 48U 800mm G2 Rack 208-230V Bottom Feed Rear Door Heat Exchanger | S4N18A |
| HPE M14 48U 800mm G2 Rack 260-290V Top Feed Rear Door Heat Exchanger | S4N19A |
| HPE M14 48U 800mm G2 Rack 260-290V Bottom Feed Rear Door Heat Exchanger | S4N20A |
| Hose Kits for RDHX | |
| HPE QD to TC 1.8 m Hose Pair for Liquid Cooled Door | R4N58A |
| HPE QD to TC 2.4 m Hose Pair for Liquid Cooled Door | R4N59A |
| HPE QD to TC 3 m Hose Pair for Liquid Cooled Door | R4N60A |
| HPE QD to TC 3.7 m Hose Pair for Liquid Cooled Door | R4N61A |
| HPE QD to TC 4.3 m Hose Pair for Liquid Cooled Door | R4N62A |
| USA Facility Adapter for RDHX | |
| HPE Cray Supercomputing 25.4 mm H2O Adapter NPT Assembly | R6W44A |
| International Facility Adapter for RDHX (only international sites that require BSPT thread) | SKU |
| HPE Cray Supercomputing 25.4 mm Water Adapter BSPT Kit | S0B09A |
| Notes: – Order one hose kit SKU and one facility adapter SKU for each door. | |
| USA Voltage CDU for RDHX | |
| HPE Cray Supercomputing 3-phase 270 kW 208 V 60 Hz 63.5 mm NA Floor Coolant Distribution Unit | R4N53A |
| HPE Cray Supercomputing 3-phase 270 kW 480 V 60 Hz 63.5 mm NA Floor Coolant Distribution Unit | R4N56A |
| EU Voltage CDU for RDHX | |
| HPE Cray Supercomputing 3-phase 270 kW 400 V 50 Hz 63.5 mm EU Floor Coolant Distribution Unit | R9B19A |
| USA facility adapter for RDHX CDU | |
| HPE Cray Supercomputing 76.2 mm H2O Adapter NPT Assembly | R6T83A |
| International Facility Adapter for RDHX CDU (only international sites that require BSPT thread) | |
| HPE Cray Supercomputing 76.2 mm Water Adapter BSPT Assembly | S0B12A |
| Notes: – Order one facility adapter SKU (R6T83A or S0B12A) for each CDU. – A CDU is required for sites that have supply water temperature at or below dew point. – The CDUs include a primary hose kit, a secondary manifold, and treated water for the secondary cooling loop to the RDHXs. – The HPE-provided secondary manifold is designed for raised-floor data centers. If the data center is on a concrete slab, the customer must provide the overhead secondary manifold that connects the CDU to the RDHXs. – Consult Site Engineering when planning a deployment or when you are unsure whether a CDU is required. | |
Service and Support
For the most up-to-date information on HPE Services, please refer to the HPE Services – Supplemental QuickSpecs, which provides a comprehensive and regularly updated overview of available services.
Technical Specifications
Environment-friendly products and approach: End-of-life management and recycling
Hewlett Packard Enterprise offers end-of-life product return, trade-in, and recycling programs, in many geographic areas, for our products. Products returned to Hewlett Packard Enterprise will be recycled, recovered, or disposed of in a responsible manner.
The EU WEEE Directive (2012/19/EU) requires manufacturers to provide treatment information for each product type for use by treatment facilities. This information (product disassembly instructions) is posted on the Hewlett Packard Enterprise website.
These instructions may be used by recyclers and other WEEE treatment facilities, as well as Hewlett Packard Enterprise OEM customers that integrate and resell Hewlett Packard Enterprise equipment.
Summary of Changes
| Date | Version History | Action | Description of Change |
|---|---|---|---|
| 21-Sep-2026 | Changed | Replaced references to "HPE GreenLake" with "GreenLake" to align with current branding standards. | |
| 16-Feb-2026 | Added | Added new product identifiers for HPE Cray Supercomputing adapter assemblies (25.4 mm and 76.2 mm NPT) to reflect updated facility adapter offerings. | |
| Changed | Updated Each Motivair Door SKU includes table to replace obsolete Motivair M‑series SKUs with new HPE M12/M14 SKUs across 42U and 48U, 600 mm and 800 mm racks. Added corresponding S‑series SKUs; removed all discontinued R‑series SKUs. Streamlined table formatting and resolved encoding artifacts. Updated hose kit and facility adapter sections to reflect new NPT and BSPT assemblies. Removed legacy Cray EX hose kit references. | ||
| Removed | Removed redundant rack‑specific SKU groupings (for example, Heavy Rack and 42U/48U variants) and associated obsolete SKUs. | ||
| 06-Nov-2023 | Changed | Updated additional SKUs and Service section | |
| 10-Jul-2023 | Changed | Overview, Standard Features and Configuration Information sections were updated. | |
| 05-Dec-2022 | Changed | Configuration Information section was updated | |
| 04-Apr-2022 | Changed | Overview, Standard Features and Configuration Information sections were updated. | |
| 06-Dec-2021 | Changed | Configuration Information section was updated | |
| 11-Oct-2021 | Changed | Service and Support section was updated. | |
| 02-Aug-2021 | New | New QuickSpecs |
© Copyright 2026 Hewlett Packard Enterprise Development LP. The information contained herein is subject to change without notice. The only warranties for Hewlett Packard Enterprise products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. Hewlett Packard Enterprise shall not be liable for technical or editorial errors or omissions contained herein.
ChilledDoor® Rack Cooling System and Motivair® are U.S. registered trademarks of Motivair Corporation.
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