Asset lifecycle extension and refrigerant transition at a large commercial office building
This maintenance project turned a significant mechanical fault into an opportunity to improve asset management and support longer-term operation. By addressing identified degradation and updating the control architecture, the project has helped strengthen the operational resilience of the building’s cooling infrastructure.
The Client
The client is a large commercial office building where dependable cooling infrastructure is critical to occupant comfort, safety and day-to-day operations. In a high-density corporate environment, the reliability of the mechanical plant is a key consideration for business continuity.
The building’s HVAC infrastructure is managed by the site’s facilities management provider, which oversees the installed base of five 20+ year-old legacy Carrier 30HXC water-cooled screw chillers. These units provide the primary cooling capacity required for the site’s environmental control. A recent technical assessment identified an atypical acoustic signature and signs of mechanical distress within the system, prompting an engineering intervention to reduce the risk of further failure.
The Challenge
In high-density commercial environments, proactive fault detection can help reduce the risk of system outages and the costs associated with unplanned downtime. Identifying mechanical degradation before it leads to broader failure is an important part of effective asset management.
The issue was first identified when a Carrier service representative attending the site for an unrelated project noted an unusual operating noise from a screw compressor before entering the plant room. A subsequent inspection confirmed that Chiller 5 had suffered a significant fault. Electrical terminal 6 broke off inside compressor A2, causing a refrigerant leak and leaving Circuit A without its charge.
To assess further risk across the rest of the plant, a comprehensive vibration analysis was performed on the remaining four chillers. The investigation identified widespread bearing wear across multiple compressors, with additional mechanical vibration detected on one unit. These findings indicated that the plant had reached a stage in its lifecycle where the risk of further failures was increasing, making isolated repairs insufficient. Instead, a broader recovery strategy was required to support long-term cooling resilience.
The Solution
The project focused on a comprehensive refurbishment rather than a standard component replacement. This approach was intended to support the client’s investment in the existing asset while helping align the building’s mechanical systems with current safety and environmental considerations.
The mechanical and chemical intervention focused on the full restoration of Chiller 5:
- Compressor overhaul: compressor A2 was replaced with a new unit. The failed compressor was subjected to a full internal forensic inspection, resulting in a detailed report outlining the precise cause of failure and the condition of all internal components.
- Fluid and filtration management: the circuit was serviced with new oil and a full set of internal and external oil filters to ensure system cleanliness.
- Refrigerant modernisation: a full refrigerant migration was executed on both circuits, transitioning the system from R134A (GWP of 1,430) to R513A (an A1-rated non-flammable refrigerant with a GWP of 631).
The project also involved a controls migration to modernise the plant’s logic and monitoring capabilities. By migrating from the legacy Pro-Dialog fixed logic to Smart View PIC6 interface, the system now benefits from enhanced control functionality, improved connectivity and greater operational visibility.
This upgrade included:
- Installation of a new control panel, featuring a modern display and advanced control boards.
- Replacement of all compressor protection boards.
- Installation of new cabling for all critical components, including thermistors, solenoid valves, transducers, protection switches and oil pumps.
- Evaporator and Condenser Tube Cleaning (ETC/CTC), supplemented by Eddy current testing to verify tube integrity and prevent future leaks.
The Result
This maintenance project turned a significant mechanical fault into an opportunity to improve asset management and support longer-term operation. By addressing identified degradation and updating the control architecture, the project has helped strengthen the operational resilience of the building’s cooling infrastructure.
The project delivered several reported outcomes:
- Asset reliability: the vibration analysis and Eddy current testing established a predictive maintenance roadmap. By identifying bearing wear indicators at an early stage, Carrier supported the transition from reactive maintenance to a more predictive, data-led maintenance strategy.
- Environmental impact: the upgrade to R513A refrigerant (GWP 631) aligns the plant with lower-GWP design standards, while supporting preparedness for evolving F-Gas regulatory requirements.
- Operational efficiency: full cooling capability was restored. The migration to the PIC6 control interface provides facilities teams with improved system management, greater visibility and updated operating logic.
This project demonstrates how Carrier can support value-engineered refurbishment strategies that enhance asset reliability, restore operational performance and address evolving environmental requirements while maximising the value of existing plant.
