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Ventilation Maintenance

Mechanical Ventilation with Heat Recovery (MVHR) Unit Maintenance Checklist

A maintenance checklist for MVHR units covering heat exchanger cleaning, filter replacement, fan checks, and condensate management — for energy-efficient building ventilation maintenance.

What is a mvhr unit maintenance checklist?

A mechanical ventilation with heat recovery (mvhr) unit maintenance checklist is a structured list of the 11 preventive maintenance tasks — covering visual, functional, cleaning, safety and record-keeping checks — that keep a mechanical ventilation with heat recovery (mvhr) 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 mvhr unit checks

  • Check external intake and exhaust grilles are unobstructed
  • Check both supply and extract fans for noise, vibration, and correct operation
  • Remove and replace or clean supply and extract air filters
  • Ensure electrical isolation is accessible and labelled
  • Record filter condition, airflow rates, and heat recovery efficiency

What is a mechanical ventilation with heat recovery (mvhr) unit?

An MVHR unit provides balanced mechanical ventilation by simultaneously extracting stale air and supplying fresh air through a heat recovery exchanger. The exchanger transfers heat from the outgoing extract air to the incoming fresh air, recovering up to 90% of the heat that would otherwise be lost. MVHR systems are increasingly common in energy-efficient and well-insulated buildings where natural ventilation is limited.

Typical MVHR 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

  • Check external intake and exhaust grilles are unobstructed
  • Inspect ductwork connections for leaks or condensation

Functional Checks

  • Check both supply and extract fans for noise, vibration, and correct operation
  • Verify bypass damper operates correctly (summer bypass mode)
  • Measure supply and extract airflow rates against design specification
  • Verify frost protection heater or defrost cycle operates correctly in cold weather

Cleaning & Housekeeping

  • Remove and replace or clean supply and extract air filters
  • Inspect the heat recovery exchanger for dust buildup and clean if required
  • Clean condensate drain tray and confirm drain is flowing freely

Safety Checks

  • Ensure electrical isolation is accessible and labelled

Record Keeping

  • Record filter condition, airflow rates, and heat recovery efficiency

Typical maintenance frequency

Suggested intervals for mechanical ventilation with heat recovery (mvhr) unit maintenance. Actual frequencies should follow manufacturer guidance and site-specific risk assessments.

Quarterly

  • Clean or replace filters
  • Check condensate drain
  • Visual inspection of unit

Every 6 Months

  • Clean heat exchanger
  • Check bypass damper
  • Verify airflow rates

Annually

  • Full service including fan checks
  • Frost protection test
  • Efficiency measurement
  • Ductwork inspection

Common faults and issues

Issues to be aware of when maintaining mechanical ventilation with heat recovery (mvhr) unit equipment.

Blocked filters drastically reducing airflow and ventilation effectiveness
Heat exchanger fouling reducing heat recovery efficiency and increasing energy costs
Condensate drain blockages causing water damage or mould growth
Bypass damper failing to open in summer, leading to overheating
Frost protection failure allowing the heat exchanger to ice up in winter

Safety and compliance notes

Key safety considerations for mechanical ventilation with heat recovery (mvhr) unit maintenance. This is general guidance only — always follow OEM instructions, statutory requirements, and your organisation's safe systems of work.

Isolate electrically before accessing internal components — some units have multiple electrical supplies
MVHR units in loft spaces require safe access and adequate working room
Handle heat exchanger elements carefully — some are fragile and expensive to replace
How PM Assist helps

Managing MVHR 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 mechanical ventilation with heat recovery (mvhr) unit documentation and ask questions like “What is the design airflow rate?” or “Where are the isolation points?” — and get source-cited answers instantly.

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

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Frequently asked questions

Manage your building documentation with AI

PM Assist gives FM teams instant access to O&M manuals, drawings, and maintenance knowledge — all searchable with AI.

  • Upload and organise building documentation
  • AI-powered search across all your manuals
  • Source-cited answers for maintenance queries
  • Team collaboration and access control
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