Pump from the refrigerator motor: 5 steps for a homemade unit

Turning an old refrigerator compressor into a functional pump is a task that combines economy, creativity and practical benefit. On average, the service life of a household compressor is 15-20 years, but after replacing the refrigerator, its engine is often sent to a landfill, although it can serve for decades in a different capacity. Such a homemade unit is suitable for pumping water from the basement, pumping air into an aquarium, pumping oil, or even creating a system of pneumatic tools.

The main advantage of the solution is minimal costs: in addition to the compressor itself, you will need parts costing up to 1000 rubles (or even improvised materials). However the power of a homemade pump will be limited by the characteristics of the original engine: a standard compressor from an Atlant or Biryusa refrigerator develops pressure up to 2-3 atm, which is enough for domestic tasks, but not enough for industrial needs.. Before you begin, evaluate the feasibility: if you need a pump for a well 30 meters deep, it is better to buy a ready-made solution.

This article contains a step-by-step analysis of the process, taking into account typical errors, connection diagrams and alternative use cases. We will not delve into the theory of thermodynamics, but we will explain the key points so that even a beginner can cope without specialized equipment.

1. Which compressor is suitable for conversion

Not every engine from a refrigerator can be adapted to a pump. Main selection criteria:

• 🔧 Compressor type: only suitable piston sealed models (marking begins with letters DK, FG or WX). Rotary or scroll compressors (found in inverter refrigerators) are extremely difficult to remake.
• ⚡ Power: optimal range - 120–300 W. Compressors more powerful than 350 W require enhanced electrical wiring and a cooling system.
• 🛠️ Condition: the engine must start without extraneous noise and overheating. You can check this by connecting it to the network for 10–15 minutes (be sure to secure it on a stable surface!).
• 🔄 The presence of three tubes: two for freon (input/output) and one for service (often sealed). The latter is useful for connecting a pressure gauge.

The best candidates for conversion are compressors from Soviet refrigerators (ZIL, Minsk, Oka) or modern budget models (Atlant, Indesit, Stinol). Avoid engines from No Frostsystems: they are designed to operate at low pressure and will quickly burn out under load.

⚠️ Attention: Compressors from refrigerators with the No Frost system have increased wear of the piston group due to frequent switching on/off. Their service life as a pump rarely exceeds 1–2 years.

If you are not sure about the model, pay attention to the technical data plate (usually pasted on the body). Look for the following parameters:

• R134a or R600a —type of refrigerant (not critical for reworking).
• 220V/50Hz —voltage and frequency (standard for Russia).
• Input: 180W —power consumption.

2. Necessary tools and materials

For basic conversion of a compressor into a water pump, you will need a minimum of equipment. Here is a complete list indicating alternatives:

Additionally, the following may come in handy:

• 🔨 Fieldman's tools: metal hacksaw, file, pliers, screwdrivers.
• 🔥 Soldering iron (power 60–100 W) - for sealing connections.
• 🛡️ Protective equipment: glasses, gloves (required when working with freon!).

If you plan to use pump for pumping oil or fuel, add to the list:

• 🧪 Chemical resistant hoses (for example, from a hydraulic system).
• 🔥 Fire extinguisher (when working with gasoline/kerosene).

3. Dismantling the compressor and preparing for work

Removing the engine from the refrigerator is the most critical stage. It is important here not to damage the tubes and not to release freon into the room. Follow the algorithm:

Step 1. Disconnection and defrosting.

Unplug the refrigerator and leave it with the door open for 24 hours. This is necessary for:

• 🧊 Complete defrosting of the evaporator (ice can damage the tubes).
• ⚡ Removing residual voltage from the capacitors.

Step 2. Dismantling the compressor.

1. Remove the back cover refrigerator (usually attached to 4-6 screws).
2. Disconnect the start relay (black box on the compressor) - just pull it up.
3. Cut the tubes cutters for copper pipes (or with a hacksaw) at a distance of 10-15 cm from compressor. Do not cut closely - you can damage the housing!
4. Unscrew the 4 bolts securing the compressor to the frame (usually a 10 or 12 wrench).

Step 3. Removal freon.

The freon remaining in the system must be vented outside or in a well-ventilated area:

1. Wear gloves and goggles.
2. Carefully file the tube (the thinner one is the freon outlet) and let the gas come out (you will hear a hissing).
3. After the hissing stops, close the tube with pliers.

⚠️ Attention: Freon R600a (used in modern refrigerators) is flammable! Do not bleed it near an open fire or heating devices.

If the compressor has not started for several years, there may be no freon in it - check by connecting it to the network for 1-2 seconds (it should hum).

What to do if the compressor does not start?

If the engine does not shows signs of life, check:

1. Starting relay — often fails (can be replaced with a universal one for 120–250 W).

2. Motor windings —call with a multimeter (the resistance between the contacts should be 10–30 Ohms).

3. Capacitor —if it is swollen, replacement is required (the capacity is indicated on the body).

4. Modification of the compressor for a pump

Now you need to adapt the compressor to work with liquid or air. The main task is to organize the inlet and outlet valves, since the standard system is designed for freon circulation.

Option 1: Water pump (low pressure, high flow).

1. Connect a hose with a coarse filter to the inlet tube (the one that leads to the evaporator). Secure with a clamp.
2. Connect the water supply hose to the outlet tube (leading to the condenser). Install on it a check valve (so that water does not return to the compressor when turned off).
3. Seal the connections epoxy resin or cold welding - the fum tape will not hold vibration.

Option 2: Air compressor (medium pressure).

1. Install at the inlet air filter (can be from car carburetor).
2. Mount at the outlet receiver (a container for smoothing out pressure pulsations). A fire extinguisher or a gas cylinder with the top cut off is suitable.
3. Add safety valve (set to 3-4 atm) - this will protect the system from rupture.

For both options:

• 🔌 Power supply: connect the compressor via the start relay (the one removed from the refrigerator). If the relay burns out, use a universal type RTK-1.
• 🌡️ Cooling: the compressor will heat up - install it on a metal plate or organize a fan blowing.

5. Connection diagrams and testing

Before the first start, check:

• 🔌 Connection polarity: the compressor should rotate clockwise (as viewed from the pulley side). If the direction is incorrect, swap the wires on the windings.
• 💧 Tightness: coat all connections with soapy water - if bubbles appear, you need to redo the joints.

Connection diagram for water pump:

[Water source] → Filter → [Compressor inlet] → [Compressor outlet] → Check valve → [Discharge hose]

Scheme for air compressor:

[Air intake] → Filter → [Compressor inlet] → [Compressor outlet] → Receiver → Safety valve → [Consumer]

Carry out the first start in this order:

1. Connect the compressor to the network via UZO (residual shutdown device) at 10 mA.
2. Start for 1–2 minutes no load (for a water pump - without water, for an air pump - with shut-off output).
3. Check the case temperature - if it heats up above 60°C, stop and improve cooling.
4. Connect the load and monitor the pressure using the pressure gauge.

⚠️ Attention: If the compressor begins to “knock” or vibrate more than usual, turn it off immediately. This is a sign of water hammer (liquid entering the cylinder) or valve failure.

6. Typical mistakes and how to avoid them

Even if you follow the instructions exactly, you can make a critical mistake. Here are the most common mistakes and ways to prevent them:

• 🔥 Overheating of the compressor:

  Cause: lack of cooling or long-term operation without breaks.

  Solution: install the compressor on a metal base and take breaks every 20 minutes.

• 💦 Water entering the cylinder:

  Cause: lack of a check valve or the vertical section of the suction hose is too long.

  Solution: use a valve and position the hose with a slope towards the water source.

• ⚡ Short circuit:

  Cause: damaged wire insulation or working in a humid environment.

  Solution: solder all connections and insulate with heat shrink tube.

• 🔊 Strong noise and vibration:

  Cause: unbalanced motor or weak fastening.

  Solution: fix the compressor on rubber shock absorbers (you can from a washing machine).

If the pump suddenly stops pumping, check:

1. The integrity of the fuse in the start relay.
2. Clogged filter (blow it with a compressed air).
3. Network voltage - if it drops below 190V, the compressor may not start.

7. Alternative uses of a homemade pump

In addition to standard tasks (pumping water, inflating wheels), a converted compressor can be used for:

• 🎨 Aerography: connect an airbrush to the output - get a budget compressor for painting.
• 🐟 Aquarium aeration: supply air into the water through a sprayer (adjust the pressure with a needle valve).
• 🔥 Forge: pump air into the coals to increase the temperature of the flame.
• 🚗 Pneumatic tools: with a 10-20 liter receiver you can connect a wrench or a spray gun.
• 🌱 Hydroponics: for circulating a nutrient solution in plant growing systems.

Each option will require modifications:

• For airbrushing need moisture separator (otherwise the paint will splatter).
• For pneumatic tools — pressure regulator with pressure gauge.
• For hydroponics — chemically inert hoses (for example, made of silicone).

If you plan to use the pump for food liquids (for example, pumping wine or honey), replace all hoses with food grade silicone and add sterilizing filter.

8. Safety precautions during operation

A homemade pump is a source of increased danger. Follow these rules to avoid injury or damage:

• 🔌 Electrical safety:

  Always connect the compressor via RCD or differential circuit breaker.

  Do not leave the pump turned on unattended.

• 💥 Pressure:

  Do not exceed the operating pressure of 2-3 atm (maximum for household compressors).

  Use a pressure gauge with a red zone marking the critical threshold.

• 🔥 Fire hazard:

  Do not use the pump for pumping gasoline or other flammable liquids without grounding and spark arrester.

  Keep the fire extinguisher at arm's length.

• 👨‍🔧 Maintenance:

  Every 50 hours of operation, check the oil level in the compressor (add compressor oil 10W-30).

  Once a year, disassemble and clean the valves from carbon deposits.

⚠️ Attention: If the compressor starts to “shoot” (popping noises are heard), this is a sign of detonation of oil vapors, immediately turn it off and replace the oil!

You need to store the homemade pump in a dry place. having previously relieved the pressure from the system. If the unit will not be used for more than a month, preserve it:

1. Blow out all hoses with compressed air.
2. Pour 10–20 ml preservative oil (for example, for chainsaws) into the cylinder.
3. Rotate the shaft by hand (by the pulley) 5-6 times.

FAQ: Frequently asked questions about remaking the compressor

Is it possible to use a compressor from an inverter refrigerator?

Technically, yes, but such compressors have a complex control system and often do not start without the original board. In addition, their service life in pump mode rarely exceeds 1-2 years due to the thin cylinder walls. It is better to choose a regular piston compressor from a Soviet refrigerator.

How to increase pump performance?

There are three ways:

1. Install receiver a larger volume (from 20 l) - this will smooth out pulsations and allow pressure to accumulate.
2. Connect two compressors in parallel (via a common receiver), but synchronization of their operation will be required.
3. Replace the pulley on the compressor with a larger diameter (the volume of suction will increase air/liquid in one stroke).

However, remember: exceeding the rated load reduces the service life of the engine by 2-3 times.

What to do if the pump pumps jerkily?

The cause of jerking is usually unstable voltage or clogged valves. Check:

• Voltage in the socket (should be 220V ± 10%).
• Integrity of the capacitor in the starting relay (if there is a malfunction, the compressor will "twitch" when starting).
• Cleanliness of the intake filter (a clogged filter creates a vacuum, which causes the engine to run unevenly).

If the problem persists, disassemble the compressor and check the condition of the piston rings.

Is it possible to convert the compressor to operate from 12V?

Direct conversion to 12 volts is impossible - the compressor windings are designed for 220V. However, there are two workarounds:

1. Use inverter 12V→220V (with a power of at least 300 W).
2. Rewind the windings yourself (requires knowledge in electrical engineering and special equipment).

The first option is simpler, but the inverter must be pure sine (regular car inverters with a modified sine wave will burn out the compressor in a few minutes).

How long will a homemade one last? pump?

The service life depends on three factors:

• Initial condition of the compressor: if it has worked in the refrigerator for 10+ years, it will serve as a pump for another 3-5 years.
• Operation mode: with a daily load of 2-3 hours resource is reduced to 1–2 years.
• Quality of service: regular replacement of oil and filters extends the life of the unit by 1.5–2 times.

With careful operation (for example, for periodic pumping of water from basement) the pump can work for 7–10 years.