The piston compressor is the most widespread air compressor in garages, workshops and on farms. Simple, rugged and cheaper to buy than a screw compressor, it remains the right choice as long as air is used from time to time rather than all day long. This guide brings together the essentials: how it works, the different types, how to choose one, what it costs and how to maintain it.
What is a piston compressor?
A piston compressor, also called a reciprocating compressor, compresses air with one or more pistons moving up and down in cylinders, just like an engine. The compressed air is sent to an air receiver, which acts as a reserve: the tools draw from it, and the compressor restarts when the pressure drops.
This receiver defines how a piston compressor is used: the machine fills it, stops, rests, then starts again. It is built for intermittent work, not for continuous air production.
How a piston compressor works
Intake and compression
On each turn of the crankshaft, the piston goes down and draws air in through the intake filter and the intake valve. As it goes back up, it reduces the volume of the cylinder: the pressure rises, the discharge valve opens and the air goes to the receiver. The motor drives the crankshaft, usually through a belt, which lets the pump turn slowly and wear less.
Single-stage or two-stage
- Single-stage: the air is compressed in one go up to the final pressure. This is the usual solution for workshop tools, around 8 to 10 bar.
- Two-stage: the air is compressed a first time in large cylinders, cooled in an intercooler, then compressed again in small cylinders. This reaches a higher pressure (12.5 bar and more) with cooler air and a pump that runs cooler. It is the choice for truck tyre inflation and tools that need pressure.
The pressure switch and control
The pressure switch stops the motor when the receiver reaches the upper set pressure, and restarts it when the pressure falls to the lower setting. A safety valve protects the receiver if the pressure exceeds the limit. This on/off operation is simple and reliable, but every start puts stress on the motor: hence the importance of a properly sized receiver.
Duty cycle: the real limit of a piston compressor
A piston compressor produces heat with every compression. It needs rest periods to cool down. The manufacturer states a duty cycle (the share of time the machine can run): this tells you whether a piston compressor suits your use.
- The compressor runs for a few minutes, then stays off for a long time: the piston compressor is in its element.
- The compressor hardly ever stops: it is working beyond its intended rhythm. It overheats, uses oil and wears quickly. A screw compressor is then a better fit.
The differences are detailed in our article piston and screw compressors: what really sets them apart, and the guide screw or piston compressor helps you decide.
Pros and cons
| Piston compressor | Screw compressor | |
|---|---|---|
| Purchase price | lower | higher |
| Working rhythm | in cycles, with rest periods | built to run continuously |
| Pressure | up to 12.5 bar and more in two-stage | 8 to 13 bar, 16 bar in the laser version |
| Noise | louder | generally quieter |
| Maintenance | simple, few tools needed | services by running hours, with kits |
| For whom | garage, workshop, occasional use, backup | workshop that uses air all day |
The advantages: a moderate purchase price, simple mechanics that any mechanic knows, good tolerance of dusty environments, and high pressure available in two-stage versions.
The limits: noise, hotter and wetter air at the outlet, and above all a use that must remain intermittent. To reduce the noise, see piston compressor too loud: how to reduce the noise.
How to choose a piston compressor
- Air flow: add up the consumption of the tools that run at the same time, in litres per minute, and add a margin. Compare machines on the same type of flow: the intake flow is always higher than the delivered flow at the outlet. Our guide what size compressor to choose explains the calculation.
- Pressure: 8 bar is enough for most workshop tools. Truck tyre inflation and some tools and machines need 10 to 12.5 bar: this is where two-stage compressors come in. See what pressure for an air compressor.
- Receiver: the bigger it is, the less often the motor starts and the more time the air has to cool. See air receiver sizing.
- Power supply: small compressors exist in single-phase; above a few kW, 380 V three-phase is required. See single-phase or three-phase piston compressor.
- Running time: if air is used for more than half the day, compare with a screw compressor before buying.
The configurator suggests the right model for your trade in a few clicks.
Our piston compressors: the E series
The E series brings together our receiver-mounted piston compressors, from 4 to 11 kW:
- E 40: 4 kW on a 100 L receiver, for small workshops and occasional use.
- E 75: 7.5 kW, 3 belt-driven cylinders, 180 L receiver on wheels, at 8 or 12.5 bar.
- E 75 HP: 7.5 kW two-stage, 12.5 bar, 300 L receiver, for truck tyre inflation and demanding tools.
- E 110: 11 kW, 3 cylinders, 320 L receiver, 1.6 m³/min at 8 bar, to supply several workstations at once.
| Model | Power | Pressure | Air flow | Price excl. VAT |
|---|---|---|---|---|
| E 40 — Piston compressor 4 kW E Series — tank-mounted piston compressors | 4 kW | On quote | ||
| E 75 — Piston compressor 7.5 kW E Series — tank-mounted piston compressors | 7.5 kW | 8 or 12.5 bar, your choice | 0.9 m³/min | On quote |
| E 75 HP — Two-stage piston compressor 7.5 kW, 12.5 bar E Series — tank-mounted piston compressors | 7.5 kW | 12.5 bar | 1.05 m³/min | On quote |
| E 110 — Piston compressor 11 kW E Series — tank-mounted piston compressors | 11 kW | 8 bar | 1.6 m³/min | On quote |
2-year warranty, spare parts available for 15 years. A detailed comparison of the four models is in our piston compressor comparison.
Installation
A piston compressor is installed level, in a ventilated, frost-free room, with space around the pump so that it can cool. Avoid closed, overheated rooms: a piston compressor that cannot breathe runs hot and wears out. If the air is used for painting or sensitive tools, add a dryer and filters: see which air dryer to choose and compressor room installation.
Maintenance
A piston compressor needs little, but regularly:
- every day: drain the receiver;
- every week: check the oil level and the air filter;
- every month: check the belt tension and condition, and the cleanliness of the cooling fins;
- oil change: at the intervals given in the manual, and at least once a year.
The full schedule is in when to service a piston compressor, and the choice of lubricant in which oil for a compressor. To have it serviced by our technicians, see our maintenance and inspection offers. In the event of a breakdown, see compressor troubleshooting: diagnosis and repair.
Piston compressor rental
For a job site, a busy season or while waiting for a repair, we also rent out the piston compressors of the E series. See our compressor rental.