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Cooling Maintenance

CRAC Unit (Computer Room Air Conditioning) Maintenance Checklist

Keep server and comms rooms cool and stable — filter, humidity, and condensate checks, refrigerant or chilled-water verification, fan and alarm tests, and redundancy.

What is a crac unit maintenance checklist?

A crac unit (computer room air conditioning) maintenance checklist is a structured list of the 10 preventive maintenance tasks — covering visual, functional, cleaning, safety and record-keeping checks — that keep a crac unit (computer room air conditioning) running safely and reliably. It groups routine checks by frequency, from daily inspections to annual servicing, so FM teams and building engineers can plan and evidence preventive maintenance.

Core crac unit checks

  • Inspect the humidifier (canister/electrode) and water treatment
  • Verify supply/return air temperatures and humidity against setpoints
  • Check and replace air filters
  • Carry out F-Gas leak checks on DX units per the system charge
  • Record temperatures, humidity, refrigerant/F-Gas, and alarm tests in the log

What is a crac unit (computer room air conditioning)?

A CRAC (computer room air conditioning) unit — or the chilled-water CRAH equivalent — provides close-control cooling and humidity management for server rooms, comms rooms, and data halls, where stable temperature and humidity are critical to equipment reliability. Units may be DX (with their own refrigerant circuit and external condenser) or chilled-water fed, often in N+1 redundant arrangements. Because the load runs 24/7 and a cooling failure can take IT offline in minutes, maintenance is rigorous: filters, humidity control, condensate management, refrigerant or chilled-water performance, fan and EC motor health, alarms, and proving the redundancy actually works.

Typical CRAC Unit maintenance checklist

A practical starting point for planned preventive maintenance. Always refer to the manufacturer's O&M manual and site-specific requirements.

Visual Checks

  • Inspect the humidifier (canister/electrode) and water treatment

Functional Checks

  • Verify supply/return air temperatures and humidity against setpoints
  • Check refrigerant circuit performance / chilled-water flow and ΔT
  • Test fan / EC motor operation, current, and any speed control
  • Confirm alarms (high temp, humidity, airflow, condensate) report correctly
  • Prove N+1 redundancy — confirm standby unit starts on duty failure/rotation

Cleaning & Housekeeping

  • Check and replace air filters — restricted airflow quickly raises rack temperatures
  • Inspect and clear the condensate drain, pump, and humidifier system

Safety Checks

  • Carry out F-Gas leak checks on DX units per the system charge

Record Keeping

  • Record temperatures, humidity, refrigerant/F-Gas, and alarm tests in the log

Typical maintenance frequency

Suggested intervals for crac unit (computer room air conditioning) maintenance. Actual frequencies should follow manufacturer guidance and site-specific risk assessments.

Monthly

  • Check filters and airflow
  • Verify temp/humidity setpoints
  • Inspect condensate and alarms

Quarterly

  • Refrigerant/chilled-water performance check
  • Humidifier service
  • Fan and EC motor check
  • Redundancy/changeover test

Annually

  • Full service and F-Gas leak check
  • Coil and condenser clean
  • Control and alarm verification
  • Update F-Gas records

Common faults and issues

Issues to be aware of when maintaining crac unit (computer room air conditioning) equipment.

Blocked filters raising rack inlet temperatures and tripping high-temp alarms
Condensate or humidifier overflow risking water near IT equipment
Refrigerant leak on DX units reducing capacity and breaching F-Gas duties
Humidifier scaling or electrode failure, losing humidity control
Standby (N+1) unit failing to start on duty failure, removing redundancy
Units fighting each other (one humidifying while another dehumidifies) wasting energy

Safety and compliance notes

Key safety considerations for crac unit (computer room air conditioning) maintenance. This is general guidance only — always follow OEM instructions, statutory requirements, and your organisation's safe systems of work.

A cooling failure can overheat IT within minutes — treat CRAC faults and alarms as urgent
F-Gas regulations require leak checks and record-keeping based on the refrigerant charge
Manage condensate and humidifier water carefully — water near IT equipment is high-risk
Prove redundancy regularly — untested N+1 is not redundancy
Only F-Gas certified engineers should work on refrigerant circuits
How PM Assist helps

Managing CRAC Unit documentation with PM Assist

PM Assist helps FM and building operations teams search their O&M manuals and building drawings in seconds. Upload your crac unit (computer room air conditioning) documentation and ask questions like “What temperature and humidity setpoints does the room run?” or “Is the cooling N+1 redundant?” — and get source-cited answers instantly.

See PM Assist answer questions about a real crac unit manual — try the live demo, no signup needed.

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