CRAC Spare Parts Guide: What to Stock On-Site for Liebert, Uniflair, and Stulz Units

Parts availability is one of the least glamorous aspects of data centre operations, and one of the most consequential. When a CRAC unit trips offline at 2 a.m. on a Sunday, the difference between a two-hour recovery and a two-week outage often comes down to whether the right spare was sitting on a shelf in your comms room.

Australian data centre operators face a particular challenge here. Local distributor stock for precision cooling components is thin compared to North America or Europe. Compressors, control boards, and humidifier cylinders for specific models routinely carry lead times of six to twelve weeks when ordered reactively. For facilities running N+1 or 2N cooling redundancy, a prolonged parts wait can erode that redundancy entirely while the failed unit sits idle.

This guide covers the spare parts worth holding on-site for the three CRAC brands most commonly installed in Australian data centres: Vertiv/Liebert (CW and Datamate series), Schneider Electric/Uniflair (InRow and Leonardo), and Stulz (CyberAir). The recommendations are grouped by component category so procurement officers can build a rationalised inventory rather than duplicating parts across brands unnecessarily.

Why Reactive Procurement Fails in Precision Cooling

Precision air conditioning components are not commodity items. A scroll compressor for a Liebert CW unit is not interchangeable with one from a Stulz CyberAir, even if both are sourced from Copeland or Bitzer. Refrigerant circuit configurations, electrical connections, and control logic differ enough that substitution is rarely straightforward.

The other factor is refrigerant transition. With R410A phase-down accelerating under the Kigali Amendment and Australia's scheduled HFC reduction milestones, some older units are becoming harder to support. Parts for R410A-charged equipment are still available, but the supply chain is tightening. Units already transitioned to R32 or R513A have their own specific component requirements. Knowing which refrigerant your units contain directly affects which compressor and expansion valve variants to stock.

For facilities running three or more CRAC units of the same model, holding one set of high-wear spares per model family is generally cost-justified. For smaller installations with one or two units, a negotiated consignment arrangement with your service provider is worth considering.

Vertiv / Liebert: CW and Datamate Series

Liebert equipment, now sold under the Vertiv brand, remains one of the most widely installed CRAC platforms in Australian data centres. The CW (Chilled Water) and Datamate (DX) series cover a broad range of room-based and close-coupled configurations.

Compressors

Datamate units use hermetic scroll compressors, typically Copeland or Danfoss units matched to the specific refrigerant charge and circuit capacity. Stocking a compressor is only practical for facilities running four or more identical units; the capital outlay is significant and the component is refrigerant-specific. For smaller sites, a documented supplier relationship with confirmed stock availability is the more realistic approach. Confirm whether your units are R410A or R32 charged before specifying any compressor spare.

Fans

EC fan motors are the most common failure point across the Liebert range. The CW series uses backward-curved EC fans with integrated motor controllers. These fail due to bearing wear, capacitor degradation, and moisture ingress over time. Replacement fans are model-specific; the physical dimensions and control interface (0-10V or PWM) must match. Hold at least one fan assembly per unit type on-site. Lead times from Vertiv distribution in Australia regularly exceed four weeks for less common frame sizes.

Humidifier Cylinders

Liebert units fitted with electrode humidifiers use replaceable cylinders that foul progressively with mineral deposits. In Brisbane and Sydney, where water hardness varies significantly by suburb and season, cylinder life can range from three months to over a year. The cylinder is a consumable, not a failure item, but running without a spare means scheduling replacements reactively. Stock two cylinders per humidifier-equipped unit and rotate on a condition basis rather than a fixed interval.

Sensors

Temperature and humidity sensors drift over time and are a frequent source of nuisance alarms and control instability. Liebert units use proprietary sensor assemblies for supply air, return air, and ambient sensing. A spare sensor set costs relatively little and can resolve a misdiagnosed control fault quickly. Calibrate sensors annually against a traceable reference; replace any sensor reading more than 1°C or 3% RH outside specification.

Control Boards

The iCOM controller used across the Liebert range is a known long-lead item. Board failures are not common, but when they occur, the unit is completely non-functional until the replacement arrives. For sites where a single unit failure would compromise cooling redundancy, holding a spare iCOM board is worth the investment. Ensure the firmware version on the spare matches the installed units before storing it.

Schneider Electric / Uniflair: InRow and Leonardo

Schneider's Uniflair range covers both in-row cooling (InRow series) and room-based perimeter units (Leonardo). The InRow units are prevalent in high-density deployments; the Leonardo covers traditional raised-floor environments.

Compressors

InRow DX units use compact scroll or rotary compressors matched to R410A or, in more recent models, R32. The compressor is housed in a sealed refrigerant circuit and is not a field-serviceable item in the traditional sense; replacement requires a licensed refrigerant technician and circuit recommissioning. As with Liebert, compressor stocking is only practical at scale. Focus instead on ensuring your service contractor holds or can access stock within an acceptable timeframe, and document that commitment in your maintenance agreement.

Fans

Uniflair InRow units use EC plug fans or axial fans depending on the model and airflow direction (front-to-rear or vertical). Fan failures in InRow units have a direct and immediate impact on rack inlet temperatures because the unit is positioned within the row rather than at the perimeter. Hold one replacement fan assembly per InRow model variant installed. For Leonardo perimeter units, the fan array typically uses multiple smaller EC motors; a single motor failure reduces airflow but does not take the unit offline entirely. Stock one motor per unit.

Humidifier Cylinders

The Uniflair Leonardo uses Carel or Humitronic electrode humidifier cylinders depending on the production year. These are not interchangeable across manufacturers. Check the humidifier manufacturer plate inside the unit before ordering spares. The InRow series does not include integrated humidification; humidity management in InRow deployments is typically handled by a separate room-level unit.

Sensors

Schneider units use a combination of NTC thermistors and capacitive humidity sensors. The supply air sensor is the most frequently replaced item. Uniflair also uses differential pressure sensors for filter monitoring; these drift and can generate false filter-change alarms. A spare pressure sensor and a spare supply air sensor cover the majority of sensor-related service calls.

Control Boards

Uniflair units use the Schneider EcoBreeze or proprietary Uniflair controller depending on the series. Board availability through Australian Schneider distribution is inconsistent. For InRow units integrated into a BMS via Modbus or BACnet, a controller failure also severs the monitoring connection, which creates a secondary problem for facilities teams relying on centralised DCIM. Holding a spare controller board for InRow units is strongly recommended where monitoring continuity is a site requirement.

Stulz: CyberAir Series

Stulz CyberAir units are well regarded for build quality and are common in Australian colocation and enterprise data centres. The CyberAir 3 is the current generation; older CyberAir 2 units remain in service at many sites.

Compressors

Stulz uses Copeland scroll compressors across the CyberAir range. The compressor selection varies by unit capacity and refrigerant type. CyberAir 3 units are available in R410A and R32 variants; the compressor part numbers differ between them. For sites running multiple CyberAir units of the same capacity, a compressor spare becomes more justifiable. Stulz Australia maintains a local parts presence, but availability for specific compressor variants is not guaranteed.

Fans

CyberAir units use EC backward-curved fans with integrated motor electronics. Stulz fans are sourced from ebm-papst and are generally available through industrial fan distributors as well as through Stulz directly, which provides some supply chain flexibility. Hold one fan assembly per installed unit. For CyberAir 2 units, confirm the fan frame size and voltage specification before ordering, as these differ from CyberAir 3.

Humidifier Cylinders

Stulz uses both electrode and resistive humidifier types depending on the unit configuration. Electrode cylinders are consumables with site-specific service life driven by water quality. Resistive elements last longer but fail without warning. The CompTrol controller monitors humidifier run hours and can be configured to generate a replacement reminder. Stock one cylinder or element set per humidifier-equipped unit.

Sensors

CyberAir units use Stulz-proprietary sensor assemblies for return air temperature and humidity. These are not interchangeable with generic NTC or capacitive sensors without recalibration. A spare return air sensor and a spare supply air sensor cover the most common fault scenarios. Stulz also uses a refrigerant pressure transducer for high and low side monitoring; these drift over time and are worth holding as a spare for units approaching five years of service.

Control Boards

The CompTrol controller is the nerve centre of the CyberAir. Board failures are uncommon but render the unit inoperable. Stulz Australia can sometimes supply boards from local stock, but this is not guaranteed for older CyberAir 2 variants. For sites where CyberAir units are the primary cooling source, holding a spare CompTrol board is a reasonable precaution. Store it in an antistatic bag in a temperature-controlled environment.

Building a Rationalised Spare Parts Inventory

The table below summarises recommended on-site stock levels by component category. These are starting points; adjust based on the number of units installed, your redundancy configuration, and your contracted service response times.

• EC fan assemblies: One per installed unit, model-specific
• Humidifier cylinders: Two per humidifier-equipped unit, consumable rotation
• Supply and return air sensors: One set per unit type
• Control boards: One per site for each controller platform installed
• Compressors: One per site where four or more identical units are installed; otherwise, documented supplier commitment
• Refrigerant pressure transducers: One per unit type for units over five years old
• Filter media: Three months' supply based on your replacement interval

Parts storage matters as much as parts selection. Control boards and sensors are sensitive to electrostatic discharge and humidity. Store them in their original packaging in a controlled environment. Label each spare with the unit model it is compatible with and the date of purchase. Rotate humidifier cylinders on a first-in, first-out basis.

Integrating Spare Parts into Your Maintenance Programme

A spare parts inventory is only as useful as the maintenance programme that deploys it. Annual preventive maintenance visits should include a parts audit: check that stocked items are within their shelf life, confirm compatibility with any units that have been modified or upgraded, and replenish anything consumed during the year.

For facilities operating under AS/NZS 3666 requirements or with ASHRAE TC 9.9 thermal compliance obligations, cooling downtime has regulatory as well as operational consequences. Documenting your spare parts holdings as part of your site's risk management plan demonstrates due diligence to auditors and insurers.

At CRAC Services Australia, we assist maintenance teams across Brisbane, Sydney, and Melbourne with parts identification, inventory planning, and procurement for Vertiv/Liebert, Schneider/Uniflair, and Stulz equipment. If you want to review your current spare parts position against your installed base, visit [https://crac.services](https://crac.services) or contact our team directly.