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Air conditioning preventative maintenance reports
The short answer
The service report is the one HVAC techs fill out most. AIRAH DA19 is the recognised maintenance schedule and AS/NZS 3666.2 maintenance is mandatory for air handling systems in commercial buildings in most states. Frequency is set by the contract, not by law.
DA19 is guidance, until it is not
AIRAH DA19 is not law. It is, however, the recognised benchmark for what "properly maintained" means, which is how it ends up mattering: work health and safety duties, equipment warranty claims, and essential safety measures obligations all lean on it. If a system fails and the maintenance history does not look like DA19, that gap is where the argument starts.
Where it becomes a legal obligation
AS/NZS 3666.2 covers microbial control in air handling systems, and maintenance under it is mandatory for systems in commercial buildings in most states. In Victoria mechanical ventilation can be a listed item on the Annual Essential Safety Measures Report under the Building Regulations 2018, and in New South Wales it can appear on the Annual Fire Safety Statement. In those cases your service records are the evidence behind somebody's annual attestation.
Readings separate a service from a visit
A checklist of ticks says somebody attended. Readings say what the plant was actually doing: suction and discharge pressures, return and supply air temperatures and the resulting temperature split, compressor current per phase, supply voltage, superheat and subcooling. Those numbers are what let the next tech see a system drifting before it fails.
Frequency follows the contract
Monthly for critical or commercial plant, quarterly for typical commercial, six monthly or annual for residential and light commercial. DA19 tabulates which tasks belong to which interval per asset type. Quarterly is the sensible default to schedule from, adjusted per site.
Who is responsible for what
The building owner or facility manager carries the maintenance obligation, usually discharged through a maintenance contract. The servicing technician records what was done and what was found. Where the system is a listed essential safety measure, the owner relies on those records when signing the annual statement.
What the report should record
- Client and site name and address, unit location and asset ID
- System type, make, model, serial number, refrigerant type, capacity in kW and install date
- Service type: monthly, quarterly, six monthly or annual
- Indoor unit checks: filters, coil, drip trays and condensate drain, condensate pump, fan
- Outdoor unit checks: condenser coil and fans, compressor mounts, oil leaks and pipework, electrical contactors and overloads, terminal tightness
- Air side checks: ducts, grilles, plenum, flexible duct condition and insulation, exhaust fans
- Readings: suction and discharge pressure, ambient, return and supply air temps, temperature split, compressor current per phase, supply voltage, superheat, subcooling
- Refrigerant added in grams, which should also appear in your refrigerant log
- Defects and recommendations with photos, technician and client signatures, and the date
What commonly goes wrong
- Checklist completed with no readings, so nothing can be trended between visits
- Filters marked as checked rather than cleaned or replaced, with no indication which
- Condensate drains left unflushed, which is the most common cause of a callback
- Refrigerant added on the service report but never recorded in the refrigerant log
- No photo of a defect that the client is being asked to pay to rectify
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Common questions
How often should air conditioning be serviced?
It is contract driven. Monthly for critical commercial plant, quarterly for typical commercial sites, and six monthly or annual for residential and light commercial. AIRAH DA19 sets out which tasks belong at which interval.
Is AIRAH DA19 a legal requirement?
No, it is guidance. But it is the recognised benchmark for properly maintained plant, which is how it becomes relevant to work health and safety duties, warranty and essential safety measures.
When is HVAC maintenance legally mandatory?
AS/NZS 3666.2 maintenance is mandatory for air handling systems in commercial buildings in most states. Mechanical ventilation can also be a listed measure on the Victorian Annual Essential Safety Measures Report or the NSW Annual Fire Safety Statement.
What readings should be on a service report?
Suction and discharge pressures, ambient, return and supply air temperatures and the temperature split, compressor current per phase, supply voltage, superheat and subcooling.
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Last reviewed: September 2026. General information for tradespeople, not legal advice. Standards and regulations change. Governing references for this page: AIRAH DA19; AS/NZS 3666.2; VIC Building Regulations 2018 (Essential Safety Measures); NSW Annual Fire Safety Statement. Confirm the current position with AIRAH before you rely on it.