How to make a compressor from a refrigerator to inflate wheels with a receiver: a complete guide

An old refrigerator that has served its purpose can become a source of parts for a useful homemade device - compressor for inflating wheels. If you are tired of spending time and money traveling to a tire shop or buying a factory pump, this project will help you save money and get a reliable tool with pressure up to 8-10 atmospheres. The main advantage of a homemade design is the ability to add receiver (storage tank), which will make the compressor operate more stable and reduce the load on the engine.

In this article we will examine a unique connection diagram with a receiver from a fire extinguisher or gas cylinderwhich is rare even in professional workshops. You will learn what parts are required, how to properly solder copper tubes, set up a pressure switch and avoid typical mistakes that cause homemade compressors to fail after a month of use. And also - how to modify the system to work with a spray gun or pneumatic tool.

What parts can be taken from the refrigerator

The main element of the future compressor is sealed compressor unit (most often brands Danfoss, Secop or Embraco). It is already designed for long-term operation under load and is capable of creating pressure up to 15-20 bar in the cooling system. In addition to this, the following from the refrigerator will be useful:

• 🔧 Start relay - necessary to start the compressor engine (usually mounted next to it).
• 🧲 Capacitor (if any) - helps smooth out starting currents.
• 🔄 Median tubes - they can be used to connect system elements.
• 🛠️ Fixing bolts and rubber shock absorbers - useful for fixing the compressor on the frame.

You should not take thermostat or evaporator —they will not be needed. But oil from the compressor there is no need to drain: it is specially designed for lubricating internal parts and is designed for high temperatures. If the oil turns black or has a burning smell, it is better not to use the compressor - this is a sign of wear on the piston group.

⚠️ Attention: Compressors from refrigerators No Frost often have a higher service life than conventional models, but they are more difficult to adapt due to integrated electronics. Before disassembling, check the markings on the compressor housing - if there are letters there NF, get ready for additional modifications to the connection diagram.

Choosing a receiver: what can be used

A receiver is a storage tank that accumulates compressed air and releases it in portions, reducing the load on the compressor. For a homemade device, the following are suitable:

• 🔥 Fire extinguisher (preferably carbon dioxide OU-2, OU-5, OU-8) - the most popular option. Its body is designed for pressure up to 150 atmospheres, and the neck is suitable for installing a pressure gauge and valve.
• ⚙️ Gas cylinder (propane or oxygen) - reliable, but requires careful cleaning of gas residues. Cylinders 5-10 liters are optimal for home use.
• 🚗 Receiver from a truck (for example, from KAMAZ or ZIL) - already has fittings for connection, but takes up a lot of space.
• 💨 Plastic canister (only for pressure up to 3 atmospheres!) - suitable for temporary solutions, but unsafe when long-term operation.

The best choice in terms of price/quality ratio is a fire extinguisher OU-5. Its capacity (5 liters) is enough to inflate 4-5 wheels of a passenger car without constantly turning on the compressor. Before using a cylinder or fire extinguisher you need:

1. Rinse with water and detergent (to remove rust or powder residues).
2. Dry with a hair dryer or in the sun.
3. Paint the outside with heat-resistant paint (optional, but will extend service life).

Necessary tools and materials

In addition to parts from the refrigerator and receiver, you will need:

Also useful:

• 📏 Pressure gauge (preferably two: for the receiver and output pressure).
• 🔌 Wires with a cross section of 1.5-2.5 mm² and terminals for connection.
• 🛡️ Safety valve (customizable on 8-10 atmospheres).
• 🔧 Clamps and fittings for connecting hoses.

⚠️ Attention: Do not use oxygen hoses for constant use - they crack over time under pressure. The best option is high hydraulic hoses pressure or polyurethane tubes with braid.

Connection diagram for a compressor with a receiver

The classic diagram includes the following elements (in the direction of movement air):

[Compressor] → [Filter drier] → [Receiver] → [Pressure switch] → [Pressure gauge] → [Outlet fitting]

Connection features:

1. Compressor inlet (usually marked arrow IN) is connected to the atmosphere through a filter (you can use a filter from VAZ carburetor).
2. Compressor output (arrow OUT) is soldered to the copper tube that goes to the receiver.
3. Pressure switch is installed between the receiver and the outlet fitting. It must be set to:
   • On when 4-5 atmospheres (lower threshold).
   • Shutdown at 7-8 atmospheres (upper threshold).

Safety valve cuts directly into the receiver and is adjusted to 10 atmospheres (the maximum permissible pressure for most passenger car tires).

For soldering copper use hard solder tubes (for example, copper-phosphorus) - it can withstand vibrations and high pressure. Connections to the receiver are best made through threaded fittings with sealing tape FUM or Tangit Uni-Lok.

How to check the compressor before assembly?

Connect it directly to the network (via the starting relay) and measure the current consumption. The norm for most models is 1.5-3 A. If the current is higher or the compressor heats up after 5 minutes of operation, its resource is running out.

Step-by-step assembly instructions

Let's look at the assembly process using the example of a compressor from a refrigerator Atlant i fire extinguisher OU-5:

1. Step 1. Preparing the compressor

   Remove the start relay and check the contacts for oxidation. If the compressor has been idle for a long time, add 50-100 ml of fresh compressor oil (for example Shell Clavus G 32) through the filling tube. To do this:

   • Unsolder the filling tube (thin copper, often bent in a loop).
   • Fill the oil with a syringe through the funnel.
   • Solder the tube back.
2. Step 2. Installation of the receiver

   In the neck of the fire extinguisher, drill a hole for threaded fitting (usually 1/4" or 3/8"). Use a tap to cut the thread. Install:

   • 🔧 Inlet fitting (from the compressor).
   • 📉 Pressure gauge (on a separate fitting or through a tee).
   • 💥 Safety valve.
3. Step 3. Electrical connection

   Assemble a circuit according to the principle:

   
   [220V network] → [Switch] → [Pressure switch] → [Compressor start relay] → [Compressor]
   

   The pressure switch (RDM-5) has 3 contacts:

   • 1 — 220V input.
   • 2 — output to the compressor.
   • 3 — grounding (be sure to connect!).

Step 4. Test run

Before turning on for the first time:

• Check all connections for tightness with a soap solution (apply with a brush - if bubbles appear, there is a leak).
• Make sure that the receiver is secured (can be welded to the frame or fixed with clamps).
• Adjust the pressure switch: upper threshold - 8 atm, lower - 5 atm.

Typical errors and how to avoid them

Even experienced craftsmen make mistakes during assembly homemade compressors. Here are the most common:

• 🔥 Overheating of the compressor - occurs due to the lack of forced cooling. Solution: install a fan from the computer (120 mm) on the compressor radiator.
• 💧 Condensation in the receiver —if you do not install a moisture separator, the water will rust the cylinder from the inside. Solution: drain the condensate after each use through the drain valve.
• ⚡ Incorrect relay setting - if the upper threshold is too high, the compressor will wear out. Solution: use a pressure gauge for accurate calibration.
• 🔊 Strong vibration —leads to loose connections. Solution: install the compressor on rubber shock absorbers (can be from a washing machine).

Another common problem is oil in the air line. This happens if the compressor is tilted or the oil is overfilled. To avoid oil getting into the hose:

• Install oil separator (can be made from a plastic bottle with an outlet at the bottom).
• Check oil level through the inspection window (if any) or by the sound of operation (a characteristic “gurgling” indicates a lack of oil).

⚠️ Attention: If the compressor begins to “knock” during operation, this is a sign water hammer —liquid has entered the cylinder. Turn it off immediately and drain the oil! Further work without repair will lead to jamming of the piston.

Modifications and improvements

The basic design can be modified for advanced tasks:

• 🎨 For a spray gun:
  • Add a second pressure regulator at the outlet (for example, FRL-unit).
  • Install fine filter (before 5 microns).
• 🚜 For pneumatic tools:
  • Increase the receiver capacity to 10-20 liters.
  • Use quick-release connections (male-female fittings).
• ⚡ Automation:
  • Connect timer to limit the time of continuous operation.
  • Install temperature sensor on the compressor (shutdown when 70°C).

For stable operation with pneumatic tools (for example, a wrench), you will need a compressor with a power of at least 1.5 kW and the receiver at 50 liters. In this case, it is better to use a compressor from industrial refrigeration equipment (for example, Bitzer or Copeland).

FAQ: Frequently asked questions

You can Is it possible to use a compressor from a refrigerator to inflate truck tires?

Theoretically, yes, but with reservations:

• The pressure in truck tires reaches 8-12 atm, so the receiver must be designed for 15+ atm (for example, gas cylinder 50 l).
• The performance of a household compressor (~100 l/min) is small for large-volume tires Inflating one. tires may take 15-20 minutes.
• It is recommended to add intermediate air cooler (can be from a copper tube rolled into a spiral).

How often do you need to change the oil in a homemade compressor?

Frequency depends on the intensity of use:

• With rare use (1-2 times a month) - once every 1-2 years.
• With regular operation (daily) - every 3-6 months.
• Signs for replacement: the oil has darkened, a burning smell has appeared, the compressor has become make noise.

Use only synthetic compressor oil (for example, Mobil Rarus 429 or Klüber Summit PTFE 46). Automotive oils are not suitable due to insufficient thermal stability!

What to do if the compressor does not gain pressure?

Causes and solutions:

• Air leak - check all connections with a soap solution.
• Wear of piston rings - knocking noise is heard during operation Solution: replacement. compressor.
• Clogged inlet filter —clean or replace.
• Faulty pressure switch —check with a multimeter (the contacts should close/open when the pressure changes).
• Low voltage in the network —the compressor may not develop full power. Use a stabilizer.

Can such a compressor be connected to a 12V battery?

No, The compressor from the refrigerator is designed for 220V. To operate from a battery you will need:

1. Inverter 12V→220V with a power of at least 1.5 kW (for example, Mystery MPI-1500).
2. Battery with a capacity of 70 Ah (otherwise it will be discharged in 10-15 minutes).
3. Protection against polarity reversal and short circuit.

Also keep in mind that the efficiency of the inverter is ~85%, so the actual power on the compressor will be lower.

Which hose is better to use to connect to the wheel?

Optimal options:

• Rubber-fabric sleeve with internal diameter 6-8 mm and working pressure 10-15 atm (marking RVD).
• Polyurethane hose with nylon braid (for example, PU-Tube 8x12).
• Flexible metal hose in PVC braid (for stationary installation).

The length of the hose should not exceed 5 meters otherwise there will be pressure loss. To connect to the wheel nipple, use brass adapter with a quick-release connection.