The Smartest Investment: Preventive Maintenance

Shocking statistic: An emergency water-cooled chiller repair after compressor failure costs 5-15 times the cost of annual preventive maintenance. Meanwhile, a regular maintenance program extends equipment life by 40-60% and reduces energy consumption by 15-25%.


A specialized maintenance technician performing monthly inspection on a 300RT screw chiller

Monthly Maintenance Schedule — Water-Cooled Chillers

# Task Tool Standard
1 Read evaporating and condensing pressures Manifold gauge Per manufacturer specification
2 Read chilled water temperatures Thermometer 6-7°C supply / 11-12°C return
3 Check lubricating oil level Visual Within specified range
4 Check compressor electrical current Clamp meter ±10% of rated current
5 Check AHU air filter cleanliness Manometer ΔP < 150 Pa
6 Check water treatment additive levels Test kit pH 7.5-8.5, TDS < 1500 ppm
7 Clean cooling tower basin Hose + brush Free of algae
8 Check AHU fan clamps and belts Visual + tension gauge Proper tension, no damage
9 Check FCU condensate drain flow Visual Free flow without deposits
10 Record energy consumption readings Power meter Compare to baseline

Quarterly Maintenance Schedule (Every 3 Months)

  • Pressure wash condenser/evaporator heat exchanger coils
  • Refrigerant leak test with electronic detector (5 g/year sensitivity)
  • Inspect and tighten electrical connections in control panels
  • Calibrate sensors and thermostats
  • Check BMS system and update programming if needed
  • Clean and inspect cooling tower fans (blades + gearbox)
  • Test electrical protection systems (overload, thermal overload)

Comprehensive Annual Maintenance

Maintenance team working on a water-cooled chiller
PowerEM team during comprehensive annual maintenance of two water-cooled chillers in an industrial facility
Equipment Annual Maintenance Estimated Time
Screw Compressor Oil analysis + fit clearance measurement + bearing inspection 2 working days
Cooling Tower Complete wash + float adjustment + structure inspection + comprehensive biological treatment 1 day
AHU Complete wash + filter replacement + damper inspection + motor greasing Half day/unit
Electrical Panels Terminal tightening + insulation test + thermal IR scan 1 day/panel
BMS System Software update + full calibration + operator training 1-2 days

Key Performance Indicators (KPIs) for Maintenance Programs

  • Mean Time Between Failures (MTBF): Should increase year over year
  • Mean Time To Repair (MTTR): Should decrease
  • PM/CM Ratio: Target = 80% preventive : 20% corrective
  • Energy Performance Indicator (EPI): kWh/m² compared to baseline
  • PM Completion Rate: Target ≥ 95% of scheduled tasks