AHU Maintenance Checklist for Hospitals

Air handling units serving OTs, ICUs, isolation rooms and wards directly affect air cleanliness, temperature, humidity and room pressure. This checklist sets out the routine preventive maintenance steps for a hospital AHU, from safe isolation through filters, coils, fans and controls to handover. Use it alongside the manufacturer's manual and your hospital's HVAC design parameters.

Checks: 37
Sections: 6
Frequency: Monthly preventive maintenance, with weekly checks for OT and ICU units
Owner: HVAC engineer or engineering supervisor

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01Planning and safe isolation
- Shutdown agreed in advance with the OT, ICU or ward in-charge
- Electrical supply isolated and locked out with a tag at the panel
- Chilled water or hot water valves closed where coil work is planned
- Required PPE worn, including mask and gloves for filter handling
- Previous PM report and open defects reviewed before starting
02Filters
- Pre-filter and fine filter pressure drop read and recorded
- Pre-filters cleaned or replaced as per schedule or pressure reading
- Filters seated correctly in frames with no bypass gaps
- HEPA filter condition and pressure drop checked on OT and critical units
- Used filters bagged and removed without shaking dust into the plant room
- Filter replacement date written on the filter frame label
03Coils, drain pan and casing
- Cooling coil fins clean and free of dust or biological growth
- Coil fins straight with no significant damage blocking airflow
- Drain pan cleaned, sloping correctly and free of standing water
- Condensate drain line and trap flowing freely
- Casing panels, gaskets and access doors sealed with no air leaks
- Internal insulation intact with no loose or wet sections
- No water carry-over seen downstream of the coil
04Fan, motor and drive
- Pulley alignment and belt deflection measured and corrected
- Belts showing glazing, fraying or cracks swapped for a matched set
- Grease added to fan and motor bearings at the OEM interval, without over-packing
- Fan and motor run without unusual vibration, rubbing or bearing noise
- Motor current recorded for each phase and compared with the nameplate
- Fan impeller clean and fixings tight
- Anti-vibration mounts and flexible connections in good condition
05Dampers, ducts and controls
- Fresh air and return air dampers move freely and are set as per design
- Fire dampers accessible and their status recorded
- Temperature and humidity sensors reading correctly against a calibrated reference
- Control valve responding to setpoint changes
- VFD or starter settings unchanged and no fault codes present
- Visible duct joints sealed and insulation intact
06Performance check and handover
- Supply air temperature and relative humidity recorded after restart
- Room pressure differential for OT and isolation rooms verified against design
- Room temperature and humidity within the set range for the area
- Plant room cleaned and all waste removed
- User department informed and handover signed
- Defects needing parts or vendor support raised as work orders

How to run this checklist well

Tag every AHU with a QR code so the technician opens the right checklist for that unit, records readings on the spot and attaches before and after photos of filters and drain pans.
Trend filter pressure drop over time instead of replacing filters only on a calendar. It shows clogging early and avoids both premature and late changes.
Schedule OT unit maintenance around the theatre list and agree it with the OT in-charge, with time built in for cleaning and checks before the first case.
Keep design parameters such as air changes, pressure and temperature ranges on the checklist itself so the technician knows what normal looks like.
Review repeat faults by unit every month. A unit that keeps failing is a candidate for an overhaul or replacement plan.

Frequently asked questions

How often should an AHU be serviced in a hospital?

Most hospitals carry out monthly preventive maintenance on AHUs, with more frequent checks on units serving OTs, ICUs and isolation rooms. Filter changes are often driven by pressure drop readings as well as the calendar. Annual tasks such as deep coil cleaning and detailed performance checks are added on top. Follow the manufacturer's manual and your hospital's infection control requirements.

Why is the AHU drain pan important for infection control?

A drain pan that does not drain fully holds standing water, which can support microbial growth inside the air handling unit. That growth can then be carried into the supply air. Keeping the pan clean, correctly sloped and free-draining, with a working trap on the condensate line, is a simple but important part of AHU maintenance in any healthcare setting.

What should be checked on an OT air handling unit?

On top of routine filter, coil and fan maintenance, OT units need checks of HEPA filter condition, room pressure relative to adjacent areas, temperature and humidity in the theatre, and air change performance as per the design. Many hospitals also coordinate periodic validation by a qualified agency. Any deviation should be reported to the OT in-charge before cases resume.

Run this checklist digitally, with QR and photo proof.

Staff scan the location, tick each check on their phone and attach photos. Missed rounds escalate automatically and every record is audit-ready.

Facility Maintenance Book a demo

Aligned with

ASHRAE guidance on ventilation of healthcare facilities
NABH Accreditation Standards for Hospitals (6th edition), FMS chapter
Equipment manufacturer's operation and maintenance manual

A practical template, not a substitute for your hospital’s own SOPs or the official standard text.

Read the guide

A Day in the Life of a Hospital Engineering Team
Hospital Energy Management: HVAC, OT Air & Costs
Cost of Downtime: Making the Case for FM Budgets

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01Planning and safe isolation

02Filters

03Coils, drain pan and casing

04Fan, motor and drive

05Dampers, ducts and controls

06Performance check and handover