# Questions to Ask a Liquid Cooling Vendor Before You Buy A practical checklist for data center operators and MEP engineers evaluating liquid cooling vendors: technical specs, warranties, fluid qualification, integration, and commercial terms. Updated 2026-11-01. Also on the [web page](https://liquidcooling.fyi/guides/questions-to-ask-cooling-vendor). Evaluating liquid cooling vendors requires technical depth and commercial rigor. This checklist covers the questions operators and MEP engineers should ask before committing. ## Technical capability ### Cooling architecture - [ ] What cooling technologies do you offer (direct-to-chip, single-phase immersion, two-phase immersion, RDHx)? - [ ] What is your maximum demonstrated rack density in production? At what supply temperature (W-class)? - [ ] Can you support mixed cooling in one facility (e.g., direct-to-chip for AI, RDHx for legacy)? - [ ] What is your typical CDU deployment model (rack, row, facility)? Why for my use case? ### Server/OEM integration - [ ] Which server OEMs have you qualified with? At what densities? - [ ] Do you offer cold plates for our specific GPU/CPU models (NVIDIA B200/GB200, AMD MI300/MI350, Intel Gaudi)? - [ ] What is the cold-plate pressure drop at design flow? How does it vary across a 72-GPU rack? - [ ] Do you provide quick-disconnects (QDs) rated for our pressure/temperature? Dripless? Hot-swappable? ### Fluid and materials - [ ] What coolant(s) do you support in the IT loop? Facility loop? - [ ] For direct-to-chip: Is the fluid qualified by the server OEM for warranty coverage? - [ ] For immersion: Does the fluid have Intel Data Center Certification for Immersion Cooling or equivalent OEM validation? - [ ] What materials are wetted in the IT loop? Compatibility with cold-plate alloys, seals, hose, QDs? - [ ] What is the fluid life expectancy? Recommended replacement interval? Testing protocol? ### Thermal performance - [ ] What supply temperature and ΔT does your design target? Which ASHRAE W-class? - [ ] What is the CDU approach temperature (IT supply vs. facility return)? - [ ] How does the system respond to rapid load transients (GPU power spikes)? - [ ] What instrumentation is included (flow, temp, pressure, conductivity, leak detection)? ## Reliability and operations ### Redundancy and resilience - [ ] What redundancy model do you recommend (N+1, 2N, cold standby)? For CDU? Pumps? Heat exchangers? Controls? - [ ] What is the switchover time on pump or CDU failure? Is it automatic? - [ ] How does the system behave during facility loop temperature excursions? - [ ] What is the single largest fault domain in your proposed architecture? ### Maintenance and serviceability - [ ] What preventive maintenance is required? Frequency? Duration? Downtime needed? - [ ] Can components be serviced without draining the IT loop? Without shutting down adjacent racks? - [ ] What spare parts do you recommend holding on-site? Lead times for critical spares? - [ ] Do you offer remote monitoring and predictive analytics? Integration with our BMS/DCIM? ### Fluid management - [ ] How is fluid quality monitored? Online sensors or manual sampling? - [ ] What is the filtration strategy? Filter change interval? Bypass capability? - [ ] How is fluid topped up or replaced? Closed-system procedures? - [ ] What is the process for fluid contamination event (biological, corrosion, particulate)? ## Commercial and contractual ### Warranties and guarantees - [ ] What warranties cover the CDU, cold plates, manifolds, QDs, and fluid? - [ ] Does the server OEM honor warranty with your cooling solution installed? Written confirmation? - [ ] Are there performance guarantees (supply temp stability, ΔT, uptime)? - [ ] What are the exclusions? Fluid degradation, improper maintenance, facility loop deviations? ### Fluid supply continuity - [ ] Who manufactures the fluid? What is the supply chain depth? - [ ] Are there qualified alternative fluids? Approval process and timeline? - [ ] Price escalation mechanism for fluid? Cap? - [ ] For two-phase fluids: Regulatory risk (EU F-gas, US AIM Act)? Phase-down schedule? ### Pricing model - [ ] Capital vs. operational cost breakdown (equipment, installation, fluid, maintenance, monitoring)? - [ ] Pricing per kW, per rack, per CDU, or per project? - [ ] Volume discounts for multi-rack/multi-site deployments? - [ ] Payment milestones tied to commissioning gates? ### Intellectual property and data - [ ] Who owns the operational data (temps, flows, alerts)? Data export rights? - [ ] Are controls proprietary? Can we integrate with our DCIM/BMS without vendor lock-in? - [ ] Source code escrow for control software? ## Project execution ### Delivery and installation - [ ] What is the typical lead time for CDU, cold plates, manifolds, QDs? - [ ] Do you provide installation supervision or turnkey installation? - [ ] What site preparation is required (power, water, drainage, structural, network)? - [ ] Commissioning sequence and duration? Load bank test or live server? ### Team and experience - [ ] How many production deployments at ≥50 kW/rack? At ≥100 kW/rack? - [ ] References: Can we speak to 2-3 customers with similar density and server OEM? - [ ] Field service coverage in our geography? Response time SLA? - [ ] Training for our operations team? Duration and format? ## Regulatory and sustainability ### Compliance - [ ] Does the system comply with ASHRAE 90.1 / 90.4 for our jurisdiction? - [ ] Pressure vessel codes (ASME, PED, CRN) for CDU heat exchangers and piping? - [ ] Electrical codes for CDU pumps, controls, leak detection? - [ ] Seismic certification for our site category? ### Environmental - [ ] Fluid GWP (global warming potential) and ODP (ozone depletion potential)? - [ ] End-of-life fluid disposal process and cost? - [ ] Water usage effectiveness (WUE) impact? Closed-loop vs. evaporative? - [ ] Waste heat recovery capability (temperature, volume, heat exchanger option)? ## Decision matrix template | Criterion | Weight (1-5) | Vendor A | Vendor B | Vendor C | |-----------|-------------|----------|----------|----------| | Max qualified density | 5 | | | | | OEM warranty coverage | 5 | | | | | Fluid qualification | 5 | | | | | Redundancy architecture | 4 | | | | | Lead time | 4 | | | | | Total cost of ownership (3 yr) | 4 | | | | | Service/SLA in region | 3 | | | | | Controls openness | 3 | | | | | Fluid supply security | 3 | | | | | Reference quality | 3 | | | | | **Weighted score** | | | | | ## Sources - Mordor Intelligence. "Data Center Liquid Cooling Market Report." 2026. https://www.mordorintelligence.com/industry-reports/data-center-liquid-cooling-market - CoolIT Systems. "Coolant Distribution Units Explained for Liquid Cooling" 3 July 2025. https://www.coolitsystems.com/resources/news/coolant-distribution-units-liquid-cooling/ - ASHRAE TC 9.9. "Thermal Guidelines for Data Processing Environments, 5th Edition." 2021. https://www.ashrae.org/technical-resources/bookstore/thermal-guidelines-for-data-processing-environments - NVIDIA. "NVIDIA GB200 NVL72 Specifications." 2026. https://www.nvidia.com/en-us/data-center/gb200-nvl72/ - Intel. "Data Center Certification for Immersion Cooling." 2025. (Cited in Mordor Intelligence, 2026) - Chemours. "Chemours and Navin Fluorine Announce Agreement to Manufacture New Liquid Cooling Product." 6 May 2025. https://www.chemours.com/en/news-media-center/all-news/press-releases/2025/chemours-and-navin-fluorine-announce-agreement-to-manufacture-new-liquid-cooling-product ## Questions ### Should I ask for a reference installation at my target density? Yes. Ask for a live site running at ≥80% of your target rack density with the same server OEM and cold-plate design. Request a site visit or detailed case study with performance data (supply temp, ΔT, PUE, uptime). ### What fluid qualifications should I require? For direct-to-chip: OEM server warranty with the specified fluid. For immersion: Intel Data Center Certification for Immersion Cooling (the first certified solution used a Shell fluid, 2025) or OEM-specific validation. Never use unqualified fluids (Mordor Intelligence, 2026). ### How do I verify a vendor's CDU redundancy claims? Request factory acceptance test (FAT) procedures for switchover time, failure detection, and graceful degradation. Ask for MTBF/MTTR data for pumps, heat exchangers, and controls. Define the resilience model in the contract (CoolIT Systems, 2025). ### What commercial terms protect me from fluid supply risk? Include fluid supply continuity clauses, qualified alternate fluid approvals, and price escalation caps. Two-phase fluorocarbon supply (Chemours Opteon) depends on the Navin Fluorine manufacturing ramp (capacity from 2026) (Chemours, 2025).