Chiller Failure and PM Backlog at a Mixed-Use Tower
At 3:10 p.m. on a Friday in July, the 600-ton Chiller B at a 28-story, 420,000 ft² mixed-use tower tripped on a compressor fault; outdoor temperature is 94°F. Chiller A is carrying 85% of the load, its condenser-water temperature is 92°F, and vibration readings are above the ISO alert level. The building has no redundant chiller; floors 18–28 report 78–80°F, and the attached 140-room hotel has received three complaints. The CMMS shows preventive maintenance completion at 61%, 14 open work orders older than 30 days, and no critical compressor spares. The operating budget has $180,000 remaining, but a replacement compressor has a nine-week lead time. The owner asks whether to run Chiller A harder, rent temporary cooling, or shut down nonessential loads. The building engineer is on leave until Monday, and the maintenance supervisor wants to cancel weekend PM to free staff.
1. What should the facilities team do in the next 72 hours, in priority order? Explain the trade-offs among life safety, tenant comfort, and damage to Chiller A.
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Priority 1 - life safety and stabilization. Confirm fire/life-safety systems are on emergency power, check upper floors for heat-related medical issues, and begin hourly rounds. Priority 2 - reduce demand on Chiller A. Raise supply-air setpoints in noncritical spaces, shut off unused conference rooms and lobby cooling, and stage spot coolers for the hotel lobby and occupied upper-floor suites. Priority 3 - protect the remaining chiller. Do not simply push it to 100%. Trend condenser-water temperature, approach temperature, amps, and vibration every two hours and set an OEM-reviewed alarm/trip threshold. Priority 4 - mobilize temporary cooling. Request a 300–500 ton rental chiller, but verify electrical capacity, footprint, hose routing, noise, and permit needs before signing. Priority 5 - escalate and communicate. Call the building engineer back, notify tenants and hotel management with a factual timeline, and keep one incident log. Do not cancel all weekend PM; reassign only noncritical tasks, because the backlog is already a root cause. The judgment is to buy capacity and monitoring while avoiding a second failure, not to trade asset risk for short-term comfort.
2. What 12-month O&M and capital recommendations follow from the CMMS and condition data? Name the monthly metrics you would report.
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Treat 61% PM completion and 14 aged work orders as a system problem, not a staffing problem. First, complete a criticality review: classify chillers, fire/life-safety, elevators, and domestic water as critical; defer noncritical PM only with written risk acceptance. Second, run a 90-day backlog-closing campaign, then shift chiller maintenance to condition-based tasks: vibration analysis, oil analysis, eddy-current testing, and condenser cleaning based on approach temperature. Third, stock critical spares-compressor, motor starter, sensors, and fuses-after a spares criticality analysis; a nine-week lead time is unacceptable for a plant with no redundancy. Fourth, fund a capital project for N+1 chiller capacity or a permanent rental connection, supported by a failure-probability and business-impact estimate, not just a price. Monthly metrics should include PM completion by criticality, backlog age, chiller approach and vibration trend, unplanned downtime hours, work-order response time, hot/cold calls per 1,000 ft², and energy use per ft². The key is to link maintenance execution to asset risk and capital planning.
3. The owner proposes canceling all preventive maintenance until the chiller is repaired to free up staff. How would you respond?
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I would agree to redeploy staff selectively, not cancel PM wholesale. The CMMS already shows 61% completion; stopping the remaining PM would raise near-term failure risk in fire/life-safety, water treatment, and electrical systems. Instead, use a criticality matrix: suspend only noncritical cosmetic and low-risk tasks, document the deferral, and reassign those hours to incident support, temporary cooling, and chiller monitoring. Keep water treatment, generator checks, fire pump tests, elevator maintenance, and electrical infrared scans on schedule. Set a 30-day review with the owner, because a blanket cancellation is a risk decision that should be documented and time-bound. If staffing is truly short, authorize overtime or a contractor for critical PM rather than trading a known backlog for a larger one. The response should show cost awareness without accepting an unsafe shortcut.