How much oil to pour into the refrigerator compressor: calculation, table and errors

The compressor is the “heart” of the refrigerator, and its correct operation directly depends on the quality and amounts of oil inside. Many owners are faced with the need to top up or completely change the oil after repairs, but not everyone knows exactly how much oil is required for a specific model. Mistakes here are fraught: a deficiency will lead to overheating and wear of parts, and an excess will lead to water hammer and valve failure.

In this article you will find accurate data on the volume of oil for different types compressors, learn to determine its level yourself and avoid common mistakes. We will also look at how the type of refrigerant affects the choice of oil and why you cannot mix different brands.

If you are planning repairs yourself, remember: working with a compressor requires care. Incorrect oil volume can reduce the service life of equipment by 30-50%, and in some cases, render it unusable building immediately after launch. Next, you will learn how to avoid these risks.

Why the amount of oil is critical for a compressor

Oil in a refrigerator compressor performs three key functions:

1. Lubrication rubbing parts (pistons, bearings, shaft).
2. Heat removal from heated surfaces.
3. Sealing gaps to maintain refrigerant pressure.

If there is too little oil, the compressor starts working "dry". This leads to:

• 🔥 Overheating motor windings (risk of interturn short circuit).
• 🛠️ Accelerated wear piston group.
• ⚡ Increased energy consumption (up to 20–25%).

But excess oil is no less dangerous. Excess fluid can:

• 💥 Cause water hammer during startup (oil will get into the cylinder and break the valves).
• 🧊 Clog capillary tube, disrupting circulation refrigerant.
• 📉 Reduce cooling capacity system.

Manufacturers calculate the optimal volume of oil with taking into account:

• 🔄 Type of compressor (piston, rotary, inverter).
• ⚙️ Power and working volume.
• ❄️ Type of refrigerant (R134a, R600a, R12 and etc.).

How to determine the amount of oil for a specific compressor

The exact amount of oil depends on the model of the compressor and refrigerator. Here 4 reliable ways find out the required volume:

1. According to the compressor marking

There is always a metal data tag on the compressor body. Look for lines like:

• Oil: 280 ml or Oil charge: 300g
• Ref./Oil: R134a/350 (where 350 is milliliters of oil).

Examples of labeling of popular brands:

• Embraco: EGX 90HLC → Oil: 260 ml
• Secop (Danfoss): SC10G → 240 ml
• Mitsubishi: C-R46K2PYE → 320 ml

2. By refrigerator model

If the tag is worn out or missing, use the compatibility table. Below is data for popular brands:

3. By type of refrigerant

Oil and refrigerant compatibility is a key factor. For example:

• R12 (outdated) → only mineral oil (150–250 ml).
• R134a → POE (polyester, 250–400 ml).
• R600a (isobutane) → mineral or alkylbenzene (200–350 ml).
• R404A, R410A → PAG or POE (300–500 ml).

4. By compressor power

In the absence of data, you can rely on the empirical formula:

Oil volume (ml) ≈ Compressor power (W) × 0.8

Examples:

• Compressor 150 W → ~120 ml of oil.
• Compressor 300 W → ~240 ml.
• Compressor 500 W → ~400 ml.

Types of compressor oils: which one to choose

Not all oils are compatible with refrigerants and compressor materials. An error in selection will lead to:

• 🧴 Dissolution of seals (if the oil is aggressive to rubber).
• 🧊 Freezing in the capillary tube (if the viscosity is incorrect).
• 🔥 Overheating due to poor thermal conductivity.

Let's look at the main types of oils and their applications:

Important: Never mix different types of oils! For example, POE and mineral oil form a sediment that will clog the system. If you don’t know which oil was filled in previously, rinse the compressor with a special solvent (for example, R141b) before replacing.

How to check compatibility?

1. Look marking on the compressor (for example, Oil: POE).
2. Check with the table above or documentation for the refrigerant.
3. If in doubt, use universal oil Emkarate RL 68H (suitable for 80% of household refrigerators).

What will happen if you fill in incompatible oil?

If the oil and refrigerant are incompatible, the following are possible:

- Gel formation (clogs the capillary tube).

- Copper corrosion (for example, POE with R600a without additives).

- Foaming (oil foams and loses its lubricating properties).

As a result, the compressor overheats and fails in 1-3 months.

Step-by-step instructions: how to fill oil into a compressor

If you decide to change the oil yourself, follow this algorithm. You will need: oil syringe (with tube), vacuum pump, pressure gauge, disassembly keys.

Step 1. Preparation

• 🔌 Unplug the refrigerator and discharge the capacitor (short-circuit the terminals with an insulated screwdriver).
• 🛠️ Remove the start relay from the compressor (usually secured with 1-2 screws).
• 🧴 Prepare the oil (volume - according to the table above). Heat it to 40–50°C (for better fluidity).

Step 2. Drain the old oil

• ⚙️ Turn the compressor over hole for refueling down (usually it is closed with a plug or valve).
• 💧 Drain the old oil into a clean container. If the oil is dark or with metal shavings - flush the compressor.

Step 3. Flushing (if necessary)

• 🧪 Pour 100–150 ml of solvent (R141b or isopropyl alcohol).
• 🔄 Rotate the compressor shaft by hand (without applying voltage!).
• 🚫 Drain the solvent and repeat 2-3 times until the liquid is clear.

Step 4. Filling with new oil

• 💉 Fill the oil into a syringe with a tube. Insert the tube into the filling hole.
• 📏 Fill in 80–90% of the calculated volume (for example, 270 ml instead of 300 ml).
• ⚖️ Rotate the compressor shaft to distribute the oil, then add to the desired level.

Step 5. Checking the level

• 🔍 Turn the compressor over with the hole facing up Level. oil should be 1–2 mm below the edge of the hole.
• 🧲 Install the plug and secure the relay.

Oil is filled in the correct volume|Filling hole plug installed|Start relay connected|Refrigerant charged (if required)|Condenser discharged-->

Step 6. Test run

• ⚡ Connect the compressor to the network for 5-10 minutes. Monitor:
  • 🔊 Noise (there should be no knocking or vibration).
  • 🌡️ Case temperature (not higher than 60–70°C).
  • 💨 Discharge pressure (must correspond to the passport one).

Signs of lack or excess oil

How to understand that there is something wrong with the oil in the compressor? Pay attention to these symptoms:

Lack of oil:

• 🔊 Increased noise (creaking, knocking) pistons).
• 🔥 Overheating of the housing (the hand does not tolerate touch).
• ⚡ Frequent protection operation (the compressor turns off after 5-10 minutes of operation).
• 📉 Reduced cooling capacity (the refrigerator does not freeze well).

Excess oil:

• 💥 Water hammer at startup (thud, compressor does not start).
• 🧊 Freezing of the capillary tube (ice at the outlet of the compressor).
• 🛢️ Oil in the circuit refrigerant (visible through the sight glass).
• 📈 Increased discharge pressure (by pressure gauge).

How to check the level without disassembling?

1. Turn off the refrigerator and let the compressor cool for 1-2 hours.
2. Remove the starting relay and turn the compressor over with the hole facing up.
3. Carefully unscrew the plug: if the oil leaks out, there is too much of it; if it is not visible, there is not enough.

Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when working with oil. Here TOP-5 mistakes and how not to repeat them:

1. Using automobile oil

🚗 Why not: Car oils (for example, 5W-30contain additives that are aggressive to copper and rubber. They are also not compatible with refrigerants.

✅ Solution: Use only specialized oils for refrigeration compressors (see table above).

2. Filling the oil "by eye"

👀 Why not: Even 20–30 ml of excess oil can cause hydraulic shock. Underfilling by 50 ml will accelerate piston wear.

✅ Solution: Always rely on the data from the compressor tag or the compatibility table.

3. Ignoring flushing when changing oil type

🧼 Why not: Residues of old oil (for example, mineral) will react with the new one (POE), forming a precipitate.

✅ Solution: Rinse the compressor with a solvent (R141b) when changing the type of oil.

4. Filling with cold oil

❄️ Why not: Cold oil thickens and does not fill all cavities. This will lead to oil starvation at startup.

✅ Solution: Heat the oil until 40–50°C (for example, in warm water) before refueling.

5. Failure to check the tightness after refueling

🕳️ Why not: If the filling hole plug is not tightened properly, oil will leak out during operation and enter the system air.

✅ Solution: After refueling, check the tightness with a soap solution (there should be no bubbles).

What to do if you overfilled the oil?

If you overfilled the oil more than normal:

1. Drain the excess through the filling hole (turn the compressor over).

2. Rotate the shaft manually to remove oil from the cylinders.

3. Run the compressor for 5 minutes without load (without refrigerant), then drain the excess. again.

If water hammer has already occurred, the valves or the entire compressor will need to be replaced.

Compatibility of oils and refrigerants: selection table

The choice of oil depends not only on the compressor model, but also on the type of refrigerant Below - compatibility table for household and semi-industrial refrigerators:

Important: For refrigerants R600a and R290 (isobutane/propane) you cannot use POEoils without special additives. These refrigerants dissolve standard POE, which leads to loss of lubricating properties.

How to choose oil for an old refrigerator?

If your refrigerator was produced before the 2000s, most likely it uses R12 or R22. Only mineral oil is suitable for them (for example, Shell Clavus G). Modern POEoils are incompatible with these refrigerants!

FAQ: Frequently asked questions about oil compressor

Is it possible to add oil without draining the old one?

Yes, but only if:

• You use same type of oil (for example, POE k POE).
• The old oil is clean (without chips and sediment).
• You add no more than 30% of the total volume.

In other cases, a complete replacement is required with flushing.

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

In household refrigerators, the oil is designed for the entire service life (10–15 years) Replacement is required only after:

• Compressor repair (replacement of pistons, valves).
• Refrigerant leaks (if oil leaked out along with it).
• Replacement of refrigerant type (for example, from R12 to R134a).

If the compressor works flawlessly - no need to top up!

What to do if the oil turns black?

Blackening of the oil signals:

• 🔥 Overheating compressor (winding insulation burnt out).
• 🛠️ Wear of the piston group (metal shavings).
• 🧴 Oil oxidation (if the refrigerator has been idle for more than a year).

Solution:

1. Drain the old oil and wash the compressor.
2. Check the resistance of the windings (should be 20–40 Ohms).
3. If there are a lot of chips, replace the compressor.

Can I use oil from an air conditioner for refrigerator?

❌ No! Oils for air conditioners (for example PAG for car air conditioners) have a different viscosity and additives. They:

• Incompatible with R600a and R134a.
• Can cause corrosion of copper in refrigeration systems.
• Have a different pour point (risk of capillary tube clogging).

Use only labeled oils Refrigeration Oil.

How to store compressor oil?

Oil for refrigeration compressors is sensitive to moisture and light. Storage rules:

• 🌡️ Temperature: 10–25°C (do not freeze!).
• 💧 Airtight container (POE-oils absorb moisture from the air).
• 🌑 In a dark place (UV rays oxidize the oil).
• ⏳ Shelf life: 2-3 years (after opening - 1 year).

If the oil becomes cloudy or sediment appears, it cannot be used!