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Water Systems Maintenance

Degasser (Deaerator) Maintenance Checklist

A maintenance checklist for system degassers and deaerators covering valve inspection, venting checks, and water quality monitoring for closed-circuit heating and cooling systems.

What is a degasser maintenance checklist?

A degasser (deaerator) maintenance checklist is a structured list of the 9 preventive maintenance tasks — covering visual, functional, cleaning, safety and record-keeping checks — that keep a degasser (deaerator) 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 degasser checks

  • Inspect the vacuum chamber for signs of corrosion or damage
  • Verify the degasser is cycling correctly and venting gases
  • Clean strainer upstream of the degasser if fitted
  • Test water quality
  • Record operational cycles, water quality results, and any faults

What is a degasser (deaerator)?

A degasser removes dissolved air and gases from closed heating or cooling water circuits. Dissolved gases cause corrosion, reduce heat transfer efficiency, and create noise in pipework and radiators. Degassers work by reducing the water pressure in a chamber, allowing dissolved gases to come out of solution and be vented. They are critical to maintaining water quality and system longevity in commercial heating and cooling installations.

Typical Degasser 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 vacuum chamber for signs of corrosion or damage
  • Check all connections and valves for leaks

Functional Checks

  • Verify the degasser is cycling correctly and venting gases
  • Check the air vent valve operates freely and is not blocked
  • Verify system water pressure remains stable during degasser operation
  • Confirm electrical supply and control signals are functioning

Cleaning & Housekeeping

  • Clean strainer upstream of the degasser if fitted

Safety Checks

  • Test water quality — dissolved oxygen, pH, and inhibitor levels

Record Keeping

  • Record operational cycles, water quality results, and any faults

Typical maintenance frequency

Suggested intervals for degasser (deaerator) maintenance. Actual frequencies should follow manufacturer guidance and site-specific risk assessments.

Monthly

  • Visual check of operation
  • Verify vent valve is clear

Quarterly

  • Water quality test including dissolved oxygen
  • Check strainer

Annually

  • Full service check
  • Inspect vacuum chamber
  • Review water treatment programme results

Common faults and issues

Issues to be aware of when maintaining degasser (deaerator) equipment.

Vent valve blocked or seized, preventing gas removal from the system
Loss of vacuum in the degassing chamber reducing effectiveness
High dissolved oxygen levels indicating the degasser is not operating correctly or air is entering the system elsewhere
Control system faults preventing the degasser from cycling

Safety and compliance notes

Key safety considerations for degasser (deaerator) maintenance. This is general guidance only — always follow OEM instructions, statutory requirements, and your organisation's safe systems of work.

The degasser operates under varying pressures — do not attempt to open the vacuum chamber while the unit is operating
Water quality in the circuit must be maintained to prevent corrosion — the degasser alone is not a substitute for proper water treatment
Ensure the unit is electrically isolated before maintenance
How PM Assist helps

Managing Degasser documentation with PM Assist

PM Assist helps FM and building operations teams search their O&M manuals and building drawings in seconds. Upload your degasser (deaerator) documentation and ask questions like “What are the legionella control requirements?” or “When was the last water quality test?” — and get source-cited answers instantly.

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

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