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HVAC PPM schedule: a task-frequency template

Updated 23 October 2026 · SEO Dons Editorial

What does a PPM schedule contain?

For every asset, four things: what it is, which tasks apply, how often, and what record each visit leaves. The tasks and intervals come from three layers in order: legal minimums, the manufacturer's instructions, and a maintenance specification for the rest. HSE's ventilation guidance says mechanical systems should be maintained in line with manufacturers' instructions, and CIBSE says to maintain as advised by the supplier or installer and, without that, to use SFG20. The Workplace Regulations add that, where appropriate, ventilation systems must be subject to a suitable system of maintenance.

PPM means planned preventative maintenance. How a contract is structured around it is on the maintenance and PPM page; this page is the schedule itself.

What goes in the asset register?

The register is what a schedule is built on; SFG20's software, for example, is set up to import one. Each line should carry:

  • Asset reference, location and make, model and serial number.
  • Refrigerant type and charge in kilograms. Labels usually show kilograms; GOV.UK says to divide by 1,000 for tonnes, then multiply by the gas's global warming potential to get tonnes of CO2 equivalent, which sets the leak-check band.
  • Rated output from the rating plate. Where several units are controlled together, the guide says their ratings may need to be aggregated.
  • Criticality, access notes and the manual reference.
  • Dates: last service, next leak check, next energy inspection, next damper test.
AssetTaskFrequencyBasis
Air conditioning, heat pumps and refrigeration with 5 tonnes CO2e or more of F gasLeak check by certified peopleEvery 12 months (5 to under 50 tonnes), 6 months (50 to under 500), 3 months (500 or more). A leak detection system lengthens these to 24, 12 and 6 monthsF-gas Regulation, Article 4
Any F-gas leak foundRepair, then re-checkRepair without undue delay; check by a certified person within one monthArticle 3; GOV.UK
Leak detection systemsCheck of the systemEvery yearGOV.UK
Air conditioning above 12 kW, units aggregated where one person controls the temperatureEnergy assessor inspectionIntervals not exceeding five yearsEPB Regulations 2012, regs 17 and 18 (England and Wales)
Cooling towers and evaporative condensersLegionella testingAt least quarterly for open systems; other checks per HSG274 Part 1HSE
Humidifiers and air washersKeep clean, monitor, keep recordsAs the risk assessment setsHSE
Fire dampersTest by a competent personAt least annually; more often in dust-laden or polluted settingsBS 9999:2017, as reported by BESA
Ventilation ductworkInspection and cleaningMinimum inspection frequency set by system type, risk and useTR19, as described by BESA
Pressure systems, where PSSR appliesExamination to a written schemeAs the written scheme setsHSE
Mechanical ventilation and plant electricsMaintenance to prevent dangerNo interval set by the RegulationsWorkplace Regulations reg 5; Electricity at Work Regulations reg 4

Whether the Pressure Systems Safety Regulations apply to a chiller or a large refrigerant circuit is for a competent person to decide. HSE says its approved code, L122, helps determine which regulations apply.

What about tasks with no fixed frequency?

Most routine tasks have none. The interval comes from the manufacturer's manual, the schedule adopted, and the plant's condition. The government inspection guide lists what matters on refrigeration plant: the condition of, damage to, or blockage of filters and heat exchangers, and the fan type and method of control. CIBSE adds coil, fan and insulation hygiene, standing water and the condition of condensate drain pans, with a visual inspection of ventilation plant at least weekly.

AssetTasks to scheduleWhere the interval comes from
Split, cassette and VRF indoor unitsFilters, coil and fan condition, condensate tray and drain, controller settingsManufacturer's manual; see the cleaning guide
Outdoor unitsCoil airflow, fan, mountings, electrical connections; leak checks by certified peopleManual; condition of the site
ChillersRefrigerant circuit, water side, controlsManual; see the chiller maintenance guide
Air handling unitsFilters, coils, fans, dampers, humidifier, drainsManual; see the AHU maintenance checklist
Controls and BMSSet temperatures, operating times, zones, sensors, and cooling running at the same time as heating (items the inspection guide says an assessor reviews)The description of operation and the manual

How do you adapt the schedule to criticality?

Keep the legal rows fixed, then tune the rest. Rank assets by what a failure costs, for example a server room against a meeting room. SFG20's schedules are colour-coded by criticality for exactly this purpose, and CIBSE notes that filters can be maintained by time or by condition, which suits critical plant where waiting for a calendar date is the wrong trigger. Record every reduction from the manufacturer's or schedule's baseline, with the reason, so it is a decision rather than a gap.

How do you turn the template into a calendar?

  1. Complete the register and work out each system's leak-check band and whether the 12 kW threshold is crossed.
  2. Enter the legal dates first: leak checks, detection system checks, the energy inspection, damper tests, legionella testing.
  3. Add the manufacturer's tasks and intervals from each manual.
  4. Apply the adopted specification for everything else, by criticality.
  5. Group visits by access: roofs, ceiling voids, plant rooms.
  6. Set the record each visit must leave, and who holds it.

What records should each visit leave?

GOV.UK says F-gas records must be kept for 5 years and cover the quantity and type of gas installed, gas added during maintenance (for example in leak repairs), and the dates and results of mandatory leak checks. Users and operators also keep the name, address and certificate number of any company used to service the equipment. The inspection report must be kept in a safe place and passed to a new owner or manager, and the guide says the building log book is normally the most suitable place for it. Legionella records follow HSE's rules, set out in the air conditioning and legionella guide.

What does this page leave out?

SFG20's task lists. Its schedules set out priority, frequency and skill level for each task, and the standard is reached through SFG20's own software, so they are not copied here. To check a contractor's version, see the maintenance contract checklist, and for what visits cost see the servicing cost page. A reader who wants quotes against their own register can send an enquiry through the site's form.

Sources

Common questions

What is a PPM checklist?

It is the per-visit list of tasks drawn from the schedule: the asset, each task, the result or reading, and the date the next visit is due. The schedule decides what appears on it; the checklist is what an engineer completes and the record you keep.

Does a PPM schedule have to follow SFG20?

SFG20 is described by its publisher as the industry standard for building maintenance specification, not as legislation. HSE points first to manufacturers' instructions, and CIBSE points to SFG20 where there is no supplier information. SFG20 says its schedules set out frequency and skill level for each task.

What is the minimum maintenance for split air conditioning?

The items fixed by law are the F-gas leak checks where the charge reaches 5 tonnes CO2 equivalent, the energy inspection above 12 kW, and, for ventilation systems, the duty to maintain them. The Workplace Regulations set a duty rather than an interval, so everything else follows the manufacturer's manual.

Does the PPM contract cover the energy inspection?

Only if it says so. A contract may name the servicing company as controller, but the landlord or occupier keeps a parallel duty. Whoever holds the duty, put the inspection's due date in the schedule so it is not missed.

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