Preventive maintenance checklist: annual calendar for technical installations

Preventive maintenance is not an expense — it is the only way to ensure your installations operate at the efficiency they were designed for, comply with current regulations and will not let you down at the worst possible moment.

An installation without preventive maintenance loses between 5% and 15% of its efficiency every year. After three or four years without a service, an HVAC unit can be consuming 30-40% more than it should. And worse still: an unexpected failure in a critical system (commercial refrigeration, data centre cooling, hotel heating in winter) can cost far more than an entire year of scheduled maintenance.

This calendar sets out the essential operations month by month for the most common installations in the commercial and industrial sectors.

January: year start and heating review

Heating and DHW:

• Verify supply and return temperatures of the heating circuit.
• Check correct operation of zone thermostats.
• Check hydraulic circuit pressure and top up if necessary.
• Verify operation of mixing and three-way valves.
• Check DHW storage temperature (minimum 60 C for Legionella prevention).

Electrical:

• Visual inspection of the main electrical panel: connection condition, signs of overheating, MCBs and RCDs.
• Trip test of residual current devices using the test button.

Industrial refrigeration:

• Verify cold room temperatures and record values.
• Check correct defrost operation.

February: Legionella prevention and hydraulic circuits

Heating and DHW:

• Bleed radiators and fan coils to remove trapped air from the circuit.
• Check safety valves and expansion vessel condition.

Legionella prevention:

• Check temperature at the most distant points of the DHW network (must remain above 50 C).
• Flush infrequently used taps and showers.
• Verify the Legionella maintenance logbook is up to date.

General:

• Inspect thermal insulation on pipework and ductwork.

March: preparing for the cooling season

HVAC:

• Complete review of cooling equipment before the warm season begins.
• Clean air filters in all indoor units.
• Clean condenser coils on outdoor units.
• Verify refrigerant charge (suction and discharge pressures).
• Check condensate drainage system operation.
• Verify compressor operation: amperage, discharge temperatures, vibrations.

Electrical:

• Verify correct operation of the reactive power compensation system (capacitor banks).

April: general commissioning

HVAC:

• Commission the cooling system if not done in March.
• Verify air flow at diffusers and grilles.
• Check time schedule programming in the management system.
• Verify free-cooling damper operation.

Industrial refrigeration:

• Clean condensers on centralised racks (before summer heat increases condensing pressures).
• Verify working pressures and adjust condensing set points.
• Inspect expansion valves and solenoid valves.

General:

• Inspect drive belts on fans and pumps.
• Lubricate bearings and moving parts.

May: consumption optimisation

HVAC:

• Verify temperature set points are adjusted for the summer season (23-25 C per RITE).
• Check air conditioning duct airtightness (leak detection via visual inspection or smoke test).
• Inspect door and window seals that affect the heat load.

Electrical:

• Thermographic survey of the electrical panel to detect hot spots indicating poor connections.
• Review contracted power: analyse whether it matches actual consumption.

Industrial refrigeration:

• Check cold room door seals.
• Verify strip curtains on loading doors are complete and in good condition.

June: peak cooling demand

HVAC:

• Verify all equipment operates correctly under maximum load.
• Check cold air supply temperatures.
• Clean air filters (second clean of the year in areas with heavy dust or pollen).

Industrial refrigeration:

• Monitor condensing pressures (rise with outdoor temperature).
• Verify condenser fan performance.
• Check correct cold air curtain formation on open display cases.

July: mid-season control

HVAC:

• Quick check of filters and condensate drains.
• Verify no water leaks from indoor units.
• Check premises temperature at various zones.

Industrial refrigeration:

• Record cold room and display case temperatures.
• Verify that defrost cycles do not cause excessive temperature rises.

General:

• Check operation of extractors and plant room ventilation.

August: summer monitoring

HVAC and industrial refrigeration:

• Continue the same checks as July.
• Pay special attention to equipment working at its limit due to high outdoor temperatures.
• Verify compressor oil levels.

Electrical:

• Inspect electrical protections on HVAC and refrigeration equipment (MCBs, fuses, contactors).

September: transition to autumn

HVAC:

• End-of-season review of cooling equipment.
• Full filter clean before switching to heating mode.
• Clean condensate trays and apply antifungal treatment if needed.

Heating:

• Preventive review of the boiler or heat pump before the heating season starts.
• Verify burner operation (gas boilers).
• Combustion analysis (efficiency, CO, flue gas temperature).
• Hydraulic circuit review: pressure, bleeding, valve condition.

October: heating commissioning

Heating:

• Commission the heating system.
• Verify operation of all terminal units (radiators, fan coils, underfloor heating).
• Programme schedules and set points for the winter season (21-23 C per RITE).
• Check zone thermostat response.

Industrial refrigeration:

• Adjust condensing set points for falling outdoor temperatures (improves efficiency).
• Verify compressor crankcase heater operation.

November: heating efficiency

Heating:

• Verify supply and return temperatures.
• Check for water leaks in the circuit.
• Inspect thermal insulation on pipework.

General:

• Emergency lighting test: autonomy check.
• Verify fire detection system operation.
• Backup generator review (if applicable): start test, fuel level, battery condition.

December: year-end and planning

General:

• Compile maintenance logbook data: operations performed, incidents, consumption.
• Assess overall installation condition and plan improvement actions for the following year.
• Verify regulatory inspection validity (OCA, Legionella, F-Gas).
• Review the maintenance contract and adjust operations if necessary.

Heating and DHW:

• Verify correct heating operation under peak demand conditions.
• Check DHW storage temperature.

Minimum frequency summary

Professional maintenance that meets the regulations

This calendar is a general reference. Each installation has its own characteristics, and the frequency of some operations depends on the output, equipment type, usage pattern and applicable regulations (RITE, RSIF, F-Gas, Royal Decree 487/2022 on Legionella).

At Acoval, we offer preventive maintenance contracts tailored to each installation, with the frequencies and operations that regulations require and experience has shown to be necessary. Our technicians document every operation in the maintenance logbook, which facilitates regulatory inspections and protects the installation owner from liability.

If you want to implement a professional maintenance plan or review the one you already have, contact us and we will prepare a proposal tailored to your installation.