Principal Operations Engineer, Mechanical — Data Center Operations

About Fluidstack We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it. We're singularly focused on delivering 10 to 100s of GWs of compute faster than anyone else, rethinking every layer of the stack. We acquire power, design and build data centers, and operate them - with teams spanning hardware and software. Speed and scale are our key differentiators. Come be a part of building civilization-scale infrastructure for AI. We hire people who care deeply about this problem space. If that is you, please apply! About the Role We are seeking a Principal Operations Engineer, Mechanical to serve as the most senior technical authority for the operational mechanical and cooling infrastructure across our hyperscale AI data center portfolio. AI workloads create thermal conditions that punish anything less than precision execution — this role exists to make sure the systems that keep our compute cold are operated, maintained, and continuously improved at the standard the workload demands. You will operate as the technical arm of senior operations leadership in the field — leading site assessments and operational audits, driving team technical readiness ahead of site activation, reviewing designs and specifications from an operational lens, and feeding operational learnings back into the design and manufacturing organization as we shift toward a productized, repeatable build model. You will be the senior voice in the room on chillers, cooling towers, CDUs, and the liquid-cooling architectures that AI infrastructure increasingly depends on. The ideal candidate has spent a career working on critical mechanical systems — in data centers, central plants, industrial cooling, or pharmaceutical or semiconductor environments — and is equally comfortable on a chiller skid, inside a P&ID review, and in front of a vendor pushing back on a flawed approach. Formal engineering credentials are valued but not required — practical depth, judgment under pressure, the ability to teach, and the discipline to keep critical infrastructure running through change are what define this role. Responsibilities Serve as the principal operational technical authority for mechanical infrastructure across the fleet, including chillers, cooling towers, CRACs/CRAHs, CDUs (direct-to-chip and immersion), dry coolers, economizers, pumping systems, water treatment, and associated piping infrastructure. Lead technical and operational site audits across active and pre-activation sites; produce operational health assessments with prioritized findings and own the remediation roadmap through closure with site leadership. Own mechanical operational readiness for new sites coming online — assess team capability, validate procedures, and personally sign off on operational handover from commissioning to steady-state operations. Review operational designs for new builds and capacity upgrades; represent the operational point of view in design forums and ensure operability, maintainability, and reliability concerns are surfaced and addressed before they are built in. Feed structured operational learnings back into the design and manufacturing organization as we shift toward repeatable, productized data center builds; reinforce patterns that work and drive out patterns that have not held up in operations. Author and approve high-risk MOPs, EOPs, and AOPs; serve as the final technical approver for high-consequence mechanical work across the fleet. Lead root cause analysis for significant thermal or mechanical events; drive corrective actions through to closure and ensure learnings propagate across all sites. Contribute to and uphold the mechanical safety program in partnership with EHS, with explicit accountability for refrigerant handling, confined space, LOTO, and high-pressure systems discipline. Partner with QA/QC during construction to provide an operational perspective on workmanship, installation quality, and pre-energization readiness. Build and deliver technical training to Field Engineers and operational teams; own the technical curriculum for mechanical content in the campus rotation and training model. Mentor Field Engineers and rising operational leaders; act as the senior technical voice in operational reviews, incident reviews, and design reviews. Basic Qualifications 10+ years of hands-on experience in mission-critical mechanical and cooling systems, with at least 5 years as the senior technical voice on a site, campus, or fleet. Data center operations experience strongly preferred; central plant, industrial cooling, pharmaceutical, or semiconductor mission-critical experience considered. Deep working command of chilled water plants, condenser water systems, CDUs and liquid cooling, air handling, refrigeration cycles, and pumping and piping systems — earned in the field, not from a textbook. Practical command of psychrometric charts, refrigeration cycles, and ASHRAE thermal guidelines for data center environments. Demonstrated ability to author, approve, and execute high-risk MOPs and EOPs in live critical environments. A track record of leading root cause analysis on significant thermal or mechanical events and driving corrective actions to closure. A track record of holding OEMs, service vendors, and contractors accountable — you know how to enforce a standard without burning the relationship. Strong written communication: operational health assessments, RCAs, procedure reviews, and design review feedback are second nature. Comfort operating as the senior technical voice across operations, design, construction, hardware, and EHS. Willingness to travel extensively across the fleet. 50-75%. Preferred Qualifications Bachelor's degree in Mechanical Engineering or related field Direct experience with direct-to-chip or immersion liquid cooling at production scale Hyperscale or large colocation operational experience at hundreds of MW+ scale EPA 608 Universal certification Trade certification or state license in HVAC; PE licensure Uptime Institute AOS or equivalent operations credential Tier III/Tier IV commissioning leadership experience Experience operating across multiple sites or as part of a global fleet operations function Experience standing up new sites from commissioning handover through steady-state Experience contributing operational requirements into reference designs or productized data center builds Salary & Benefits Competitive total compensation package (salary + equity). Retirement or pension plan, in line with local norms. Health, dental, and vision insurance. Generous PTO policy, in line with local norms. The base salary range for this position is $150,000 - $250,000 per year, depending on experience, skills, qualifications, and location. This range represents our good faith estimate of the compensation for this role at the time of posting. Total compensation may also include equity in the form of stock options. We are committed to pay equity and transparency. Fluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law. You will receive a confirmation email once your application has successfully been accepted. If there is an error with your submission and you did not receive a confirmation email, please email View email address on click.appcast.io with your resume/CV, the role you've applied for, and the date you submitted your application-- someone from our recruiting team will be in touch.