Orange Recruitment is seeking a Mechanical HVAC Engineer to join our client's Dublin-based Service & Engineering Team. This is an excellent opportunity for a technically strong, solutions-focused HVAC professional to play a key role in the maintenance, optimisation, and commissioning of complex heating, ventilation, air conditioning, and air-handling systems across a diverse client portfolio. Working both independently and alongside project and service teams, you will be responsible for ensuring HVAC plant and associated mechanical systems operate at peak performance, delivering safe, reliable, and energy-efficient results for customers. Responsibilities: Provide high-quality service, maintenance, and technical support for HVAC systems-including AHUs, chillers, heat pumps, dehumidification systems, ventilation plant, and associated mechanical equipment-in line with industry standards and safety regulations. Diagnose mechanical and control-system faults, carrying out corrective actions, component replacements, and adjustments to restore system performance and efficiency. Recommend suitable replacement parts, upgrade options, and refurbishment solutions to support long-term asset reliability and energy performance. Conduct detailed performance assessments, including airflow, pressure, temperature, and moisture measurements, using approved diagnostic tools and engineering procedures. Commission new HVAC installations, ensuring correct configuration, system balancing, performance verification, and compliance with project specifications. Produce clear, accurate service reports, commissioning records, and health & safety documentation after each site visit. Identify opportunities for system optimisation, upgrades, or additional engineering support and communicate these to the relevant internal teams. Work collaboratively with colleagues on multi-site or time-critical projects, providing technical support when required. Contribute to continuous improvement of service processes, maintaining full compliance with health, safety, and environmental standards. Engage in ongoing training, skills development, and certification renewals to maintain technical proficiency. Provide cross-department technical assistance (e.g., project engineering or technical support) when required and approved by management. Requirements: Minimum 3 years' hands-on experience working with HVAC or mechanical building services systems in a service, maintenance, or commissioning capacity (essential). F-Gas certification and strong working knowledge of refrigeration principles (essential). Solid understanding of HVAC engineering, including air handling, ventilation, dehumidification, heat transfer, and system controls. Proven ability to diagnose and resolve mechanical, electrical, and control-related faults. Competent in the use of diagnostic instruments for airflow, pressure, moisture content, temperature, and system performance measurement. Proficient with digital tools such as Excel, Word, and service management applications. Experience with airflow and psychrometric calculations is highly desirable. HNC/HND or degree in Mechanical, Building Services, or Electrical Engineering (preferred).