Remaking an ammonia refrigerator: from theory to practice with minimal risks

Ammonia refrigerators are rare “dinosaurs” among household appliances today, which are still found in garages, workshops or at dachas. Their main advantage is their unpretentiousness and ability to operate from minimal energy sources (for example, a kerosene lamp or gas burner). However, over the years, such units lose efficiency: ammonia leaks, tube corrosion, and seal wear. Instead of sending the refrigerator to a landfill, you can modernize transfer it to a modern refrigerant, replace the compressor, or even adapt it to power supply.

In this article we will analyze all stages of remodeling from diagnosing the condition to testing the updated system. You will learn what materials and tools required, how to avoid common mistakes (for example, incorrect soldering of copper pipes), and what to do if, after upgrading, the refrigerator does not cool. We will pay special attention to replacing ammonia with freon R134a or R600a this is the most popular option among craftsmen, since these refrigerants are safer and more accessible.

⚠️ Warning: working with ammonia and refrigerants requires strict adherence to safety precautions. Even a small leak of ammonia can cause burns to the mucous membranes, and incorrect refilling with freon can lead to a compressor explosion. If you are not confident in your skills, entrust the remodeling to professionals.

1. Diagnostics: is it worth redoing?

Before taking up the tools, evaluate feasibility of repair. Ammonia refrigerators manufactured before the 2000s often have worn parts that are difficult to find for sale. Here are the key points to check:

• 🔍 Case and seals: inspect the door for cracks, check the rubber gaskets - if they are dry, the refrigerator will not be airtight.
• ⚙️ Pipes and radiator: ammonia systems usually have steel or copper tubes. Look for traces of corrosion, green deposits (a sign of copper oxidation) or swelling.
• ⚡ Energy source: if the refrigerator ran on gas/kerosene, assess the condition of the burner and heat exchanger. It is often easier to replace them than to repair them.
• ❄️ Cooling capacity: turn on the unit for 2-3 hours. If the temperature in the chamber does not drop below +10°C, the system requires a major overhaul.

If at least 3 out of 4 points are in poor condition, remodeling may cost more than buying a used electric refrigerator. However, there are exceptions:

⚠️ Attention: Soviet-made refrigerators (for example, "Morozko", "ZIL", "Biryusa-18") often have unique parts that are incompatible with modern analogues. Before purchasing materials, check the technical documentation or retro equipment forums.

2. Choosing a new refrigerant: ammonia vs freon

The main task during remodeling is to replace ammonia (R717) with a safer refrigerant. Ammonia is toxic, has a pungent odor and requires high pressure in the system (up to 20 atm), which complicates repairs. Alternatives:

• ❄️ Freon R134a: the most popular option. It is non-toxic, but requires complete flushing of the system from oil (ammonia refrigerators use mineral oil, incompatible with R134a).
• 🔥 Freon R600a (isobutane): is environmentally friendly, but explosive if leaked. Suitable for small chambers (up to 200 l).
• ⚗️ Mixture R404A/R507: used in industrial systems. Expensive, but effective for large refrigerators.

Optimal for domestic needs R134a. Its advantages:

— The pressure in the system is lower (up to 12 atm), which reduces the load on the tubes.

— Compatible with most modern compressors.

— Easy to buy in cylinders of 1–5 kg.

However, there is nuance: ammonia systems are designed for a different type of oil. When switching to freon, you will need to:

1. Rinse the system with a solvent (for example, R141b).
2. Replace mineral oil with polyester oil (POE).
3. Check the tightness of all connections (freon leaks through microcracks).

3. Tools and materials: what to buy in advance

For a complete remodel. required specialized equipment. Some tools can be rented (for example, a vacuum pump or a manifold for refueling). data-i="123">Approximate price (RUB)

Additionally, you may need:

• 🔧 Soldering station with silver solder (for copper tubes).
• 🧴 Sealant for refrigeration systems (for example, Loctite 577).
• 📏 Pressure gauges for pressure control (blue - low, red - high).

If you plan to replace the compressor, choose a model with a similar cooling capacity. For Soviet refrigerators with a volume of 100–150 liters, a compressor with a capacity of 80–120 W) is suitable (for example, Danfoss NL8FJ or Secop (Danfoss) BD35F).

4. Step-by-step instructions: how to convert to freon

The conversion process will take 2-3 days and includes 5 key stages. order to avoid mistakes.

Step 1: Freeing the system from ammonia

⚠️ This is the most dangerous step. Work outdoors or in a garage with forced ventilation.

1. Disconnect the refrigerator from the power source.
2. Wear a respirator, gloves and safety glasses.
3. Connect a gas vent hose to the service port (usually located on the back wall). Lead the other end into a container with water (ammonia dissolves in water, reducing the concentration in the air).
4. Slowly open the valve. Do not release ammonia directly into the atmosphere - this violates environmental standards and is dangerous to health.

Step 2: Flushing systems

Ammonia refrigerators contain mineral oil, which is incompatible with freon. To flush:

1. Pour solvent into the system (for example, R141b) through the service port.
2. Connect the compressor and run the solvent through the circuit for 10-15 minutes.
3. Drain the used liquid and repeat the procedure 2-3 times.

What will happen if you do not flush the system?

The remaining mineral oil will react with freon, forming acids. This will lead to corrosion of the compressor and tubes, and will also shorten the service life of the refrigerant by 2-3 times.

Step 3: Changing the oil and filter drier

After flushing:

1. Install a new one filter drier (select according to the diameter of the tubes).
2. Fill polyester oil (POE) through the compressor crankcase. Volume - according to the instructions for the compressor (usually 150–300 ml).
3. Check the tightness of all connections with a soap solution (if bubbles appear, there is a leak).

Stage 4: Evacuation

Before When filling with freon, the system must be pumped out of air and moisture:

1. Connect the vacuum pump to the service port.
2. Pump out the air for 30–60 minutes until the pressure drops to -1 bar.
3. Close the valve and leave the system under vacuum for 10–15 minutes. If the pressure does not rise, there are no leaks.

Step 5: Filling with freon

Use scales for accurate dosage refrigerant:

1. Connect the freon cylinder through the manifold (blue hose - to the cylinder, yellow - to the service port).
2. Open the cylinder valve and fill the system, monitoring the weight on the scales - 80–120 g of freon per 100. l chamber volume.
3. After refueling, check the pressure with a pressure gauge: in operating mode it should be 0.5–1.5 bar on the suction side and 8–12 bar on the discharge side.

5. Replacing the compressor: when necessary

If the old compressor is worn out or incompatible with the new refrigerant, it will have to be replaced. Signs of malfunction:

• 🔊 Loud noise during operation (knocking, vibration).
• ⚡ Case overheating (temperature above 70°C).
• ❄️ Low cooling capacity (does not cool below +15°C).
• 💡 Frequent activation protection (the compressor turns off after 5-10 minutes of operation).

Compressors from modern refrigerators are suitable for replacement (for example, ATLAS COPELAND or Embraco). Main selection criteria:

Replacement process:

1. Disconnect the old compressor by cutting the tubes with a pipe cutter.
2. Install the new compressor on vibration mounts (they dampen noise).
3. Solder the copper tubes using silver solder and a torch.
4. Check the tightness with a soap solution.

⚠️ Attention: when soldering, avoid overheating the tubes - this can lead to their deformation. Optimal burner temperature: 700–800°C.

6. Upgrading the power system: from gas to electricity

Many ammonia refrigerators operated from a gas burner or a kerosene lamp. There are two ways to switch them to power:

Method 1: Installing an Electric Heater

Suitable for absorption refrigerators (for example, "Morozko-3"). data-i="245">100–200 W 100–200 W.

• ✅ Pros: ease of installation, low cost (a heating element will cost 500–1,000 rubles).
• ❌ Cons: high energy consumption (electricity consumption will increase 2-3 times compared to compressor models).

Method 2: Replacement with a compressor unit

More effective, but complex option. You will need:

1. Remove the absorber and condenser.
2. Install the compressor, evaporator and capillary tube.
3. Fill the system with freon (as described in section 4).

Such repairs will cost 10,000–20,000 rubles., but will reduce energy consumption by 5–7 times.

For power supply from a 220 V network you will need:

• 🔌 PVS cable 3×1.5 mm² (to connect the compressor).
• 🛠️ Thermoregulator (for example, Danfoss 077B6013).
• ⚡ Automatic switch at 6–10 A (for protection against overloads).

7. Testing and troubleshooting

After upgrading, the refrigerator needs to be tested within 24 hours. Here is what to check:

Typical problems after rework:

• 🔥 The compressor does not start: check the power supply, thermostat and start relay.
• ❄️ The refrigerator does not cool: possible freon leak or blockage in the capillary tube.
• 💧 Condensation on the back wall: Thermal insulation is broken or the thermostat is incorrectly adjusted.

If the refrigerator works, but consumes too much electricity, check:

1. Temperature in the room (optimally - 18–22°C).
2. The condition of the door seal (when worn, the cold “leaks away”)).
3. Thermostat settings (set to the middle position).

8. Care after modernization: how to extend the service life

A converted refrigerator will last longer if you follow simple rules:

• 🧹 Cleaning the condenser: every 6 months, remove dust from the rear grill with a vacuum cleaner or brush.
• ❄️ Defrost: even in systems with No Frost times per year, turn off the refrigerator and let the ice melt naturally.
• 🔌 Network stability: use a surge protector to protect against power surges.
• 🛠️ Prevention: check freon pressure and condition once every 2 years oil.

For absorption refrigerators (with heating elements) it is important:

— Do not cover the top grill (this impairs heat transfer).

— Use only distilled water in the cooling system (if provided design).

If the refrigerator is used seasonally (for example, in the country), before preservation:

1. Unplug and defrost.
2. Wipe the internal surfaces with a soda solution (1 tbsp per 1 liter of water).
3. Leave the door ajar for ventilation.

FAQ: Frequently asked questions about converting ammonia refrigerators

Is it possible to convert an ammonia refrigerator to freon yourself if you have no experience?

Theoretically, yes, but the risks are high. Main difficulties:

• Working with ammonia requires protection of the respiratory tract and skin.
• Errors when soldering tubes will lead to freon leaks.
• Incorrect filling can damage the compressor.

If you have never had dealing with refrigeration equipment, it is better to invite a specialist or practice on an unnecessary unit.

How much does it cost to completely remake an ammonia refrigerator in a service center?

The price depends on the amount of work:

• Refrigerant replacement + flushing: 5,000–10,000 rub.
• Installation of a new compressor: 8,000–15,000 rub.
• Conversion from gas to electricity: 10 000–20,000 rub.

Total: 15,000–35,000 rub. depending on the condition of the refrigerator.

Which freon is better for an old refrigerator: R134a or R600a?

R134a more universal:

• Suitable for refrigerators with a volume of >150 liters.
• Less risks of leaks (non-explosive).
• Easier to find on sale.

R600a more profitable for small cameras:

• More energy efficient by 10–15%.
• Cheaper (a 500 g cylinder costs ~800 rubles).

But requires caution: with a concentration in the air >31 g/m³ it becomes explosive.

What to do if, after filling with freon, the refrigerator does not cool?

Causes and solutions:

1. Lack of freon: refill the system, monitoring the weight on the scales.
2. Air in the system: bleed it through the service port and repeat the evacuation.
3. Clogged capillary tube: purge the system with nitrogen or replace the capillary.
4. Faulty compressor: check the windings multimeter (the resistance should be 20–50 Ohm).

Is it possible to use an ammonia refrigerator without modification if it is still working?

Yes, but with caveats:

• Ammonia is toxic - even a small leak is dangerous to health.
• Old systems consume a lot of energy (2-3 times more than modern ones).
• Spare parts for repair are difficult to find.

If the refrigerator is used occasionally (for example, on summer cottage), you can operate it in its original form, but:

• Regularly check the tightness of the connections.
• Do not leave a working refrigerator unattended.
• Store food only in sealed containers (ammonia can give them a specific taste).