Numbers on the refrigerator relay: how to decipher the markings and avoid mistakes when replacing

Have you ever looked into the “heart” of the refrigerator, trying to figure out why it suddenly stopped freezing or started buzzing loudly? If yes, then you probably noticed a small box with contacts and mysterious numbers - start protection relay. This part, despite its modest size, plays a key role in the operation of the compressor, and the numbers on its body are not just a random set of symbols, but a starting protection relay a code that determines compatibility with your refrigerator model. Many users mistakenly believe that the relay is a universal part, and when replacing it is enough to select "similar" in appearance. However.

Many users mistakenly believe that a relay is a universal part, and when replacing it, it is enough to choose a “similar” one in appearance. However a discrepancy between the relay markings and the parameters of the compressor can lead to failure of the latter after just a few days of operation. In this article we will look at what is hidden behind the numbers on the relay body, how to interpret them correctly, and why ignoring this data costs the price of a new compressor (and sometimes a refrigerator).

You will learn not only about marking standards (for example DANFOSS 103N0210 or ASCO R-134), but also about how these numbers are related to current characteristics, type of refrigerant and even the climate class of your refrigerator. And for those who are planning independent repairs, we have prepared step-by-step instructions for checking the relay and a compatibility table for popular models.

What is a start-up relay and why is it needed

A start-up protection relay is an electromechanical or electronic devicethat performs two critical functions:

• 🔌 Starting the compressor: at the moment of switching on, the relay supplies a short-term high current (2-3 times higher than the rated one) necessary to overcome inertia rotor.
• 🛡️ Overheat protection: if the compressor runs for too long or an overload occurs, the relay opens the circuit, preventing the motor from failing.

Without a relay, the compressor will either not start at all, or will burn out after a few minutes of operation. At the same time not all relays are interchangeable they differ in:

• 🔢 Current characteristics (rated and starting current).
• 🔧 Mounting type (on the compressor or separately on frame).
• ⚡ Supply voltage (220V or 120V for imported models).
• ❄️ Refrigerant type (for example, a relay for R134a is not suitable for R600a without adaptation).

It is these parameters that are encrypted in numbers on the relay body. For example, marking 103N0210-56 from Danfoss indicates:

• 103 — series of relays (for household refrigerators).
• N — type of protection (normally open contact).
• 0210 — current characteristics (2.1 A for nominal current).
• 56 — modification for a specific compressor.

Deciphering the numbers: standard designations and their value

The numbers and letters on the relay are not a random set, but manufacturer codewhich contains information about technical parameters. Let's look at the most common labeling standards.

1. Relay Danfoss (series 103, 104, 105)

Danish company Danfoss is one of the leaders in the production of start-up relays for refrigerators. Their marking usually has the format XXX N XXX-XX, where:

• XXX — series (for example, 103 for household refrigerators, 104 for commercial ones).
• N —type of protection (N — normally open, C —combined).
• XXX —rated current (for example, 0210 = 2.1 A).
• XX —modification (may indicate compatibility with specific compressors. Embraco or Secop).

Example: 103N0210-56 — relay series 103 with a rated current of 2.1 A, modification 56 (suitable for compressors Embraco EGX 90H).

2. Relay ASCO (R series, T)

The Italian brand ASCO uses markings of the form R-XXX or T-XXX, where:

• R — relay for refrigerators on R134a.
• T — relay for refrigerators on R600a (isobutane).
• XXX - current characteristics (for example, R-134 - for a current of 1.34 A).

Important: relays ASCO often have a color-coded housing (for example, red for R600a, blue for R134a). Ignoring this will lead to incorrect operation of the compressor or its breakdown.

3. (Termex, RTK)

Russian and Ukrainian manufacturers (for example, Termex or RTK) use simplified labeling, where the numbers usually indicate:

• First digit - relay type (1 - start-up protection, 2 - current).
• Second and third - rated current (for example, 125 = 1.25 A).
• Letters - climate class (T - tropical, U - moderate).

Example: RTK-1-125U —start-up relay with a current of 1.25 A for a moderate climate.

Compatibility table of relays and compressors

To simplify the selection of relays, we We have compiled a compatibility table for popular models of refrigerators and compressors. Please note: the data is relevant for most household refrigerators, but always check the device data sheet.

⚠️ Attention: If your refrigerator was manufactured after 2020, check the type of refrigerant in the documentation. Since 2021, many manufacturers have switched to R600a (isobutane) instead of R134a, which requires the use of special relays marked T-series.

How to check the refrigerator relay for functionality

If the refrigerator does not turn on or the compressor works intermittently, the first thing you need check - start-up protection relay. To do this, you do not need to be a professional craftsman: a multimeter and electrical knowledge are enough.

Step 1: External inspection

Remove the relay from the compressor and inspect it for:

• 🔥 Melted contacts (indicates a short circuit).
• 💨 Foreign smell of burning (coil burnt out).
• 🔌 Cracks on the case (may lead to false triggers).

Step 2: Continuity of contacts

Put the multimeter into continuity mode and check:

1. Resistance between contacts 3 and 4 (should be 0–50 Ohm is the starting winding).
2. Resistance between 2 and 3 (should be infinity —open contact).

If the device shows 0 or 1 (open/short circuit) - the relay is faulty.

Step 3: Checking operation

Connect the relay to the compressor and apply 220V voltage. A working relay should:

• 🔊 Emit click when turned on (activation of the starting contact).
• 🔄 After 1-2 seconds open the circuit (if the compressor did not start).

⚠️ Attention: If the relay does not click or constantly keeps the contact closed, it must be replaced. Continuing operation with a faulty relay will lead to overheating and failure of the compressor (replacement cost - from 8,000 rubles).

Typical errors when replacing a relay and how to fix them avoid

Even experienced craftsmen sometimes make mistakes when replacing the start-up relay. Here are the most common of them and ways to prevent them:

What happens if you install a relay with the wrong current?

If the rated current of the relay is lower than required (for example, 1.6 A instead of 2.1 A), the contacts will overheat and burn out. If the current is higher, the compressor will not receive a sufficient starting impulse and will not start.

• ❌ Ignoring the type of refrigerant: relay for R134a is not suitable for R600a (and vice versa). This is due to different starting currents pressure in the system.

  ⚠️ Attention: Refrigerant R600a (isobutane) requires a relay with marked T-series or Danfoss 103N with index 56/63. Using an unsuitable relay may result in explosive situation (isobutane is flammable!).

• ❌ Current mismatch: if the rated current of the relay less than that of a compressor, the contacts will quickly burn out. For example, for a compressor Embraco EGX 90H (current 2.1 A) relay 103N0160 (1.6 A) will not be suitable.
• ❌ Incorrect connection of contacts: there are usually marks on the relay S (starting winding), R (working), C (general). By mixing them up, you risk burning out the compressor windings.
• ❌ Purchase of a universal relay: cheap "universal" relays (for example, RTK-U) often do not provide the correct starting current and reduce the life of the compressor.

To avoid mistakes, follow a simple rule: the marking on the new relay must completely match the original (except for minor modifications, for example, 103N0210-56 i 103N0210-63).

Where to buy a relay for a refrigerator and how not to run into counterfeit

You can purchase a start-up protection relay in the following places:

• 🛒 Specialized spare parts stores (for example, "Cold-Service", "TeploKholod"). Plus: guarantee of the original product. Minus: the price is higher than from resellers.
• 🌍 Internet platforms (AliExpress, eBay, Yandex Market). Plus: wide range. Minus: high risk of counterfeit.
• 🔧 Service centers (for example, authorized Samsung or LGPlus: 100% compatibility. Minus: the price may be 2-3 times higher.

So as not to buy. fake, pay attention to:

• 🏷️ Marking quality: on the original relay, the numbers and letters are clear, without blurred edges.
• 🔍 Case material: fakes are often made of fragile plastic that breaks when pressed lightly.
• 📄 Certificate availability: official dealers always have documents for the goods.

Average cost of the original relay:

• Danfoss 103N: 800–1,500 rubles.
• ASCO R/T: 600–1,200 rubles.
• RTK: 300–700 rubles.

⚠️ Attention: On AliExpress they often sell relays with “universal” markings (for example, 103N0000). Such parts are not certified and can damage the compressor. Buy only from trusted sellers with a rating above 98%.

Frequently asked questions about the refrigerator relay

Is it possible to replace the relay yourself, without call a technician?

Yes, if you are confident in your skills in working with electricity. The main thing is to check the markings of the old relay and choose an identical analogue. However, if the compressor does not start even after replacement, the reason may be disconnect the refrigerator from the network, check the markings of the old relay and select an identical analogue. However, if the compressor does not start even after replacement, the cause may be turn-to-turn short circuit in the windings - this will require diagnostics from a specialist.

What to do if there is no marking on the relay?

If the label is erased, find the marking on the compressor (usually a sticker with the model and technical data). way - measure the compressor current pliers and select a relay according to the compatibility table. Relays with current are suitable for most household refrigerators 1.6–2.5 A.

Why a new relay right away burns out?

This is a problem if there is incompatibility in current or type of refrigerant. For example, if you installed a relay on 1.6. A for a compressor with current 2.1 A, the contacts will overheat. Also check:

• Condition starting capacitor (if it is faulty, the current at startup exceeds the norm).
• Network voltage (at low voltage the relay may not trigger).

Can I use a relay from another refrigerator?

Only if they are marked completely coincide. For example, a relay from Atlant with marking 103N0210-56 is suitable for Samsung RT-32 with the same compressor. But if the models are different, the risk of incompatibility is high - it is better to buy a new one.

How to extend the service life of the relay?

To make the relay last longer:

• 🔌 Follow for voltage stability on the network (use a stabilizer during surges).
• 🧹 Regularly clean capacitor from dust (overheating shortens service life).
• ❄️ Do not overload the refrigerator with food - this increases the load on the compressor and relay.