How to make a compressor from an old refrigerator: a step-by-step guide with photos and diagrams

An old refrigerator that has served its purpose is not just scrap metal, but a potential source of useful parts. One of the most valuable elements is compressorthat can be adapted for new tasks: from inflating tires and painting to creating a pneumatic tool or even a mini sandblaster. With the right approach, a homemade compressor will cost several times less than a factory one, and will not be inferior in performance to budget models.

However, before starting work, it is important to assess the condition of the unit. Compressors for household refrigerators are designed to last for many years of continuous operation, but their power and pressure are limited. For example, a standard motor from Atlant or Indesit produces 6–8 atm is enough for painting small parts, but not enough for professional pneumatic tools. In this article, we will look at how to safely dismantle the compressor, connect it to electricity and air piping, and also avoid common mistakes that lead to breakdowns or injuries.

⚠️ Warning: Working with refrigeration equipment requires knowledge of electrical safety. The compressor contains refrigerant (freon), which, if leaked, can cause poisoning or explosion in a confined space. If you are not confident in your skills, contact a specialist.

What tools and materials will be needed

To make a compressor from a refrigerator, you do not need rare parts - most of the components can be found in the garage or at the nearest market. Here is the basic set:

• 🔧 Tools: screwdrivers (Phillips and flathead), pliers, hacksaw, drill, set of wrenches, soldering iron (for connecting wires).
• 🔌 Electrics: cable with plug (cross-section not less than 1.5 mm²), button on/off, 10–16 A fuse, capacitor (if required for starting).
• 💨 Air duct: high pressure hose (for example, from a car compressor), adapters for fittings, check valve, pressure gauge (0–10 atm), receiver (you can use a fire extinguisher or gas cylinder).
• 🛠️ Consumables: fum tape, sealant, clamps, electrical tape, metal paint (to protect the body from corrosion).

If you plan to use the compressor for painting, this will also come in handy moisture separator —it removes condensation from compressed air, preventing defects on the surface being painted. To inflate tires, a check valve and a pressure gauge are enough.

Removing the compressor: step-by-step instructions

The first stage is to carefully remove the compressor from the refrigerator. It is located on the rear wall at the bottom and is attached to the frame with four bolts. Before starting work:

1. Unplug the refrigerator and let it stand for 2-3 hours - this will reduce the refrigerant pressure in the system.
2. Turn the unit upside down or lay it on its side to provide access to the motor.
3. Bite it off with wire cutters refrigerant pipes (do not saw! - chips may get inside the system) at a distance of 10–15 cm from the compressor.
4. Disconnect the starting relay (usually it is attached to the motor housing) and remember the location of the terminals.
5. Unscrew fastening bolts and remove the compressor.

⚠️ Attention: Do not turn on the compressor immediately after dismantling! Refrigerant or oil may remain in the system and escape through open pipes under pressure. Before the first start, be sure to blow out the pipes with compressed air (for example, from a car pump).

Disconnect the refrigerator from the mains and discharge the system|Bite off the refrigerant pipes (do not cut!)|Remove the start relay and remember the connection diagram|Blow out the pipes with compressed air before the first start|Check the integrity housing for cracks-->

Scheme for connecting the compressor to electricity

The refrigerator compressor operates from a 220 V network, but it is required to start starting relay (it is responsible for the initial moment of switching on). In most models (Samsung, LG, Biryusa), the relay is attached directly to the motor housing. If it is burned out or lost, you can use a universal relay RTK-X or DANFOSS 103N0010.

Standard connection diagram:

• 🔌 Phase (L) goes to the relay contact marked S or Start.
• 🔄 Zero (N) connects to the common motor contact (usually the middle pin).
• ⚡ Starting winding connects to the contact M or Main on the relay.

For ease of control, add an on/off button and a fuse to the circuit. If the compressor does not start, check:

• The integrity of the motor windings (call with a tester - the resistance should be 10-30 Ohms).
• The serviceability of the capacitor (if it is missing, the motor will hum, but not spin).
• The mains voltage (below 200 V - the compressor may not start).

What to do if the compressor hums but does not start?

Most likely the problem is in the starting capacitor or relay. Try to briefly (for 1–2 seconds) close the contacts on the relay with a screwdriver - if the engine starts, it means the relay is faulty. If not, check the capacitor or motor windings for breaks. S And M on the relay with a screwdriver - if the engine starts, it means the relay is faulty. If not, check the capacitor or motor windings for an open circuit.

Making a receiver and air duct

Without a receiver, the compressor will turn on too often, which will shorten its life. The following is suitable as a container for compressed air:

• 🔥 Old fire extinguisher (be sure to check for corrosion!).
• ⛽ Gas cylinder (propane or carbon dioxide) - first fill it with water to remove residues gas.
• 🛢️ Homemade tank from a pipe with a diameter of 200–300 mm and a wall thickness of at least 3 mm.

The minimum volume of the receiver is 20–30 liters. Anything less makes no sense: the compressor will overheat. To connect the compressor and receiver, use metal tubes or high pressure hose (for example, from the hydraulic system of a car). A check valve is installed immediately after the compressor - it prevents the reverse flow of air when turned off.

Air duct assembly diagram:

1. Compressor - check valve tool.
2. The following are installed on the receiver: a pressure gauge, a safety valve (adjustable to 8–10 atm), a drain valve for condensate.
3. From the receiver there is a flexible hose with a quick-release connection for connecting a tool.

First starting and testing the system

Before turning on for the first time:

1. Check all connections for leaks (you can use a soapy solution - if there is a leak, bubbles will appear).
2. Make sure that the safety valve is working properly and is set to 8-10 atm.
3. Fill into the compressor compressor oil (through the refrigerant hole) - usually 100-150 ml is enough.

Turn on the compressor and watch the pressure gauge. Normal operation:

• 📈 The pressure should rise smoothly, without jerking.
• 🔊 The motor runs smoothly, without extraneous knocks or vibrations.
• 🌡️ The body heats up, but does not burn (maximum +60–70°C).

⚠️ Attention: If the compressor turns off 5-10 seconds after starting, this is a sign of operation thermal protection. Reasons: low voltage in the network, faulty relay or overload. Let the motor cool and check the circuit.

Typical mistakes and how to avoid them

Even when following the instructions exactly, beginners make mistakes that lead to breakdowns or injuries. Here are the most common:

• 🔌 Wrong connection of the windings → the motor hums, but does not start. Solution: check the connection diagram of the relay and capacitor.
• 💥 Lack of a safety valve → risk of receiver rupture. Solution: install a valve set to 8–10 atm.
• 🌊 Ignoring condensation → water enters pneumatic tools. Solution: drain the moisture from the receiver after each use.
• 🔥 Compressor overheating → thermal protection is triggered. Solution: do breaks every 15–20 minutes of operation.

Another common problem is air leak through connections. To avoid it, use fum tape or anaerobic sealant for threaded connections and tighten the clamps with force. If a leak occurs through the compressor housing (for example, from under the cover), then the gasket is damaged - it needs to be replaced.

Modernization and improvement of a homemade compressor

The basic design of a compressor and receiver is already functional, but it can be modified for convenience and safety:

• 📉 Pressure regulator (gearbox) - will allow you to fine-tune output pressure for different tools.
• 🔋 Automatic on/off —a pressure sensor (pressostat) will start the compressor when the pressure drops below a set level.
• 🎨 Fine filter —removes oil vapors and fine dust, important for painting work.
• 🔇 Sound absorption —wrap the compressor with soundproofing material (for example, vibroplast) or install it on rubber shock absorbers.

If you plan to use a compressor for sandblasting, add it to the system moisture and oil separator - this will extend the life of the abrasive and protect the equipment from corrosion. For stable operation under load, you can connect two compressors in parallel (for example, from a refrigerator and a freezer), increasing productivity.

⚠️ Attention: When upgrading, do not exceed the maximum pressure indicated on the compressor housing (usually 8–10 atm). Installing a more powerful pressure switch or removing a safety valve can lead to an explosion of the receiver!

FAQ: Frequently asked questions about homemade compressors

Can I use a compressor from a freezer?

Yes, compressors from freezers (Liebherr, Beko) are often more powerful than those from refrigerators and produce pressure up to 10 atm. However, they are noisier and consume more electricity. Before use, check the condition of the windings and oil.

How long can the compressor operate without stopping?

Continuous operation for more than 20–30 minutes is not recommended - the motor overheats, which leads to wear of the windings. Optimal mode: 15 minutes of work, 10 minutes of rest. For long-term loads, install a blower fan.

What kind of oil should be poured into the compressor?

Use compressor oil on a synthetic basis (for example, Shell Coreena S4 P 100 or Mobil Rarus 429). The oil is not suitable for car engines - it forms carbon deposits at high temperatures. Replace every 50–100 hours of operation.

Is it possible to connect an air impact wrench to such a compressor?

Yes, but only if the tool is designed for low air consumption (up to 150–200 l/min). Professional impact wrenches require 300+ l/min - a homemade compressor cannot cope with such a volume. For reliable operation, use a receiver with a volume of 50+ liters.

Which hose to choose for the air duct?

The optimal option is high pressure hose with an internal diameter of 8–10 mm (for example, PVC hose with reinforcement or rubber hose for pneumatic tools). Avoid garden hoses - they cannot withstand pressure above 3-4 atm.