We are seeking a mechanically biased Commissioning Manager to join a major mission-critical data centre project in Hayes. You'll lead the commissioning of key mechanical systems and coordinate closely with electrical and BMS teams to ensure seamless delivery. This is an excellent opportunity to work on a high-profile facility with a forward-thinking project team. Key Responsibilities * Lead mechanical commissioning activities (L1–L5) including HVAC, chilled water, pumps, and CRAC/CRAH units. * Coordinate with electrical and controls commissioning teams to align schedules and handovers. * Review and approve commissioning method statements, RAMS, and test scripts. * Interface with client commissioning agents and subcontractors throughout all stages. * Maintain up-to-date commissioning trackers, test records, and final handover documentation. * Support integrated systems testing (IST) and attend daily commissioning meetings. * Ensure compliance with UK regulations, H&S protocols, and project QA/QC standards. * Identify risks, escalate issues, and drive resolution to keep commissioning on track. Requirements * Proven experience commissioning mechanical systems on data centres or other critical infrastructure projects. * Solid mechanical background – HNC/HND/Degree in Mechanical Engineering or equivalent. * Strong working knowledge of HVAC systems, chilled water circuits, mechanical plant, and BMS interfaces. * Experience across ASHRAE/BSRIA commissioning levels (L1 to L5). * Comfortable leading multidisciplinary teams and liaising with clients and consultants. * Excellent documentation and reporting skills. * Eligible to work in the UK. Desirable * Prior work on hyperscale or co-location data centre builds. * SMSTS and valid CSCS (Black/Gold) card. * Familiarity with integrated systems testing (IST). * Commissioning certification (BCxA, NEBB, ACG) or equivalent is a plus. What’s on Offer * £400 - £450 per day * Long-term opportunity with a leading main contractor or consultancy * Potential for follow-on projects in the UK and Europe