What is preventive maintenance?
Preventive maintenance (often shortened to PM) means looking after equipment on a plan instead of waiting for it to break. You clean, check, test and replace worn parts at regular intervals, so small problems are found while they are still cheap to fix.
A familiar example is a car service. You do not wait for the engine to fail on the highway. You service the car every few months or every few thousand kilometres. Preventive maintenance applies the same idea to air conditioners, solar plants, pumps, lifts, generators and electrical panels.
It is also called planned maintenance. The two terms are used almost interchangeably.
A simple example to understand it
Meet Farah, who looks after the air conditioning at an office building in Dubai. Instead of waiting for a unit to stop cooling, her contractor visits every month and does the same checks:
- Clean the filters and coils.
- Check the gas pressure and the electrical connections.
- Test the thermostat and listen for unusual noise.
- Record the readings and note anything that looks worn.
In March, the technician notices a fan motor drawing more current than before. It is replaced during the visit, in an hour, with a part that was already in stock. Had it been ignored, it might have failed in July, in the hottest week, and taken a day of emergency work to fix.
Types of preventive maintenance
- Time-based. Work is done at fixed intervals, such as monthly or quarterly, whatever the condition of the equipment.
- Usage-based. Work is triggered by how much the equipment has been used, such as running hours or number of cycles.
- Condition-based. Work is triggered when a reading or inspection shows wear, such as high temperature or vibration. Where this uses sensor data to forecast failure, it is called predictive maintenance.
Most small and mid-sized firms start with time-based schedules because they are simple to plan and to price in a contract.
Preventive vs corrective vs breakdown maintenance
| Preventive | Corrective | Breakdown | |
|---|---|---|---|
| When it happens | On a schedule, before failure | After a fault is found | After equipment fails |
| Planned? | Yes | Usually | No |
| Cost pattern | Small, regular | Varies | Often high and urgent |
| Typical document | Scheduled work order | Work order from a service ticket | Urgent work order |
Read more about corrective maintenance and breakdown maintenance.
Why preventive maintenance matters
- Fewer breakdowns. Problems are caught early, so there are fewer urgent call-outs.
- Longer equipment life. Clean, tested equipment wears more slowly.
- Predictable cost. A planned visit is easier to budget than an emergency.
- Proof for clients. If the work is recorded visit by visit, you can show a client exactly what you did, which is what an annual maintenance contract promises.
Common mistakes with preventive maintenance
- Having a schedule but no record. If the visit is not written down, you cannot prove it happened or spot patterns.
- Using the same checklist for every asset. A solar inverter and a chiller need different checks.
- Booking the next visit later. If the next visit is not fixed before the technician leaves, it drifts.
- Ignoring the findings. A note about a worn part that nobody acts on is the same as not noticing it.
How ZEP360 handles preventive maintenance
ZEP Service schedules recurring visits against the contract and the unit being maintained, so each planned visit exists before it is due. Preventive maintenance schedules and reminders run automatically, spare parts used on a visit are scanned from van stock, and the equipment's visit history stays on its record. When a visit is done, the next one is already waiting, and renewal alerts warn you before a contract lapses. See field service management software for how this fits together.
Related terms
Annual Maintenance Contract · Corrective Maintenance · Breakdown Maintenance · Work Order · Service Level Agreement · Facility Management
Frequently Asked Questions
What is the difference between preventive and predictive maintenance?
Preventive maintenance follows a fixed schedule or usage trigger, whether or not anything looks wrong. Predictive maintenance uses readings or sensor data to forecast when a part will fail, and acts only then. Predictive needs more data and tools, so most firms begin with preventive.
How often should preventive maintenance be done?
It depends on the equipment, its manufacturer's guidance, how heavily it is used and the environment. Monthly, quarterly and yearly visits are common. Start with the manufacturer's recommendation, then adjust using what your visit records show.
Is planned maintenance the same as preventive maintenance?
In everyday use, yes. Both mean maintenance carried out on a plan before failure. Some firms use planned maintenance to include corrective work that is scheduled in advance, so check how your contract defines the terms.
What should a preventive maintenance checklist include?
A good checklist lists the asset, the checks to be done, the readings to be recorded, the parts to be replaced if worn, and a sign-off. Keep it specific to the equipment type, and short enough that technicians complete it on every visit.
Is preventive maintenance cheaper than fixing things when they break?
Usually, over time, because small planned jobs avoid larger emergency repairs and downtime. It is not free, so match the effort to the importance of the equipment. A critical chiller deserves a tighter schedule than a spare room fan.
Who does preventive maintenance?
It can be your own technicians or an outside contractor under an annual maintenance contract. Either way, each visit should have a work order that records what was checked and who signed it off.
Related Terms
