Constant Air Volume (CAV) Unit Maintenance Checklist
A maintenance checklist for CAV units including damper checks, reheat coil inspection, and airflow verification — relevant to building operations teams managing constant-volume ventilation.
What is a cav unit maintenance checklist?
A constant air volume (cav) unit maintenance checklist is a structured list of the 9 preventive maintenance tasks — covering visual, functional, cleaning, safety and record-keeping checks — that keep a constant air volume (cav) unit 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 cav unit checks
- Inspect ductwork connections for air leaks
- Verify fixed damper position matches design airflow rate
- Clean airflow sensing elements where fitted
- Check that fire dampers upstream and downstream are accessible for testing
- Record measured airflow rate and supply temperature
What is a constant air volume (cav) unit?
A constant air volume unit delivers a fixed volume of conditioned air to a zone regardless of the heating or cooling demand. Temperature control is achieved by varying the supply air temperature through a reheat coil rather than changing the airflow rate. CAV systems are typically used in spaces with stable and consistent environmental requirements such as laboratories, server rooms, or clean rooms.
This checklist is one of 34 in our HVAC maintenance checklists, covering air handling units, fan coils, chillers, VRF, ductwork and extract systems — filters, coils, refrigerant and damper checks.
Typical CAV 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 ductwork connections for air leaks
- Check unit casing and insulation for damage
Functional Checks
- Verify fixed damper position matches design airflow rate
- Measure supply airflow and compare to design specifications
- Test reheat coil valve or electric element operation
- Verify zone temperature sensor calibration
Cleaning & Housekeeping
- Clean airflow sensing elements where fitted
Safety Checks
- Check that fire dampers upstream and downstream are accessible for testing
Record Keeping
- Record measured airflow rate and supply temperature
Download the free CAV unit maintenance checklist PDF
Get all 9 tasks as a printable PDF — free, no signup needed. Keep a copy in the plant room, attach it to work orders, or share it with your maintenance contractor.
Typical maintenance frequency
Suggested intervals for constant air volume (cav) unit maintenance. Actual frequencies should follow manufacturer guidance and site-specific risk assessments.
Quarterly
- •Verify airflow rate against design
- •Check reheat operation
Annually
- •Full airflow commissioning check
- •Inspect reheat coil condition
- •Verify controller calibration
Common faults and issues
Issues to be aware of when maintaining constant air volume (cav) unit equipment.
Safety and compliance notes
Key safety considerations for constant air volume (cav) unit maintenance. This is general guidance only — always follow OEM instructions, statutory requirements, and your organisation's safe systems of work.
Reference standards and frameworks
- United Kingdom
- SFG20 schedules and CIBSE Guide M
- North America
- ASHRAE/ACCA Standard 180 (HVAC inspection and maintenance)
Frameworks commonly referenced when planning cav unit maintenance programmes. Always confirm the requirements that apply to your site and jurisdiction.
Managing CAV 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 constant air volume (cav) unit documentation and ask questions like “What are the recommended service intervals?” or “Where are the isolation points?” — and get source-cited answers instantly.
See PM Assist answer questions about a real cav unit manual — try the live demo, no signup needed.
Take this checklist with you
Download the branded PDF, generate a custom version for your asset, or run AI search across all your building documentation.
Related free tools
Further reading on cav unit maintenance
Compliance topics for cav unit maintenance
Frequently asked questions
When should a CAV system be used instead of VAV?
How do you balance a CAV system?
Can a CAV system be energy-efficient?
What are the noise implications of CAV vs VAV?
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- Upload and organise building documentation
- AI-powered search across all your manuals
- Source-cited answers for maintenance queries
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