When the refrigerator suddenly stops freezing, but the light inside is on and the motor does not start - in 70% of cases The start relay is at fault. This small but critical element is responsible for starting the compressor, and its malfunction leads to breakdown of the entire system. Selecting a suitable relay is more difficult than it seems: you need to take into account the type of compressor, current characteristics, compatibility with the brand of refrigerator and even climatic operating conditions.
In this article we will look at how identify a relay malfunction, decipher the markings on the case, select an analogue according to the parameters and avoid typical mistakes when replacing. Let us separately dwell on the nuances for inverter compressors and refrigerators with the No Frostsystem, where the requirements for relays are stricter. If you have never encountered repairing equipment, don’t worry: the instructions are adapted for beginners, with photographs, diagrams and step-by-step videos (links to which you will find in the relevant sections).
Signs of a faulty starting relay: when it’s time to fix it change
The first signal about problems with the relay is the compressor does not start., although the refrigerator is connected to the network. But there are also less obvious symptoms that are often confused with a broken thermostat or a freon leak:
- 🔊 Clicks without starting the motor. The relay is activated (a characteristic click is heard), but the compressor does not start working. This indicates a break in the winding or jamming of the starting mechanism.
- ⏱️ Cyclic on-off. The refrigerator starts for 5-10 seconds and immediately turns off. This is how a relay behaves with burnt contacts or a faulty bimetallic plate.
- 🔥 Overheating of the relay body. If touching the relay causes a burn, this is a sign of a short circuit in the coil or an incorrectly selected current rating.
- ❄️ Insufficient cooling. The compressor works, but does not develop the required power due to problems with the starting winding (the relay does not switch it on time).
⚠️ Attention: If the refrigerator does not respond at all turns on (no light, indicators do not light up), the problem is not in the relay, but in the surge protector, plug or control unit. Check the voltage in the socket with a multimeter before diagnosing the relay.
For an accurate diagnosis, disconnect the refrigerator from the network, remove the relay (it is attached to the compressor with latches or screws) and inspect it visually. Melted contacts, a swollen case or a burning smell are a direct reason for replacement. If there are no external defects, a tester will be required (more on this in the next section).
How to check the starting relay with a multimeter: step-by-step instructions
Before buying a new relay, make sure that the old one is really broken. To do this, you will need a multimeter (even a budget model for 300–500 rubles will do) and a screwdriver. Follow the algorithm:
- Disconnect the refrigerator from the network and wait until the capacitors are discharged (5-10 minutes).
- Remove the relay from the compressor. It is usually secured with plastic clips or a single screw. Gently pull it up without using excessive force.
- Inspect the contacts. If they are blackened or melted, the relay must be replaced.
- Ring the coil:
- Set the multimeter to resistance measurement mode (200 Ohm).
- Connect the probes to the coil terminals (usually the two outermost ones contact on the relay).
- The resistance should be within 20–50 Ohm. Indications "0" or "1" (break) indicate a malfunction.
- Remove the top cover of the relay.
- Press the plate with a screwdriver - a click should be heard.
- If the plate does not return to its original position or there is no click, the relay is faulty.
⚠️ Attention: Some modern relays (for example, for inverter compressors LG or Samsung) have electronic filling. Checking them requires an oscilloscope - with a multimeter you can only make sure there is no break. In such cases, it is easier to replace the relay with a known working one for the test.
Disconnect the refrigerator from the mains|Remove the relay from the compressor|Ring the coil (20–50 Ohms)|Check the bimetallic plate (click)|Inspect the contacts for melting-->
Types of starting relays: which one is suitable for your refrigerator
Relays are divided into three main types, and they impossible can be used interchangeably. An error in selection will result in the compressor either not starting or burning out after a few minutes of operation.
| Relay type | Application | Features | Examples of models |
|---|---|---|---|
| Tablet (DCL) | Old Soviet refrigerators (Minsk, ZIL, Biryusa), some Atlant | Round case, mechanical, with a bimetallic plate. Works only with asynchronous compressors. | RTK-1, RTK-X, DCL-08A |
| Rectangular (RCO) | Modern refrigerators (Indesit, Ariston, Beko), compressors Danfoss, Secop | Plastic case, can be collapsible. Suitable for compressors with a starting winding. | RCO-407, RCO-410, V2R4 |
| Electronic (PTC, POS) | Inverter refrigerators (LG, Samsung, Liebert), models with No Frost | Without mechanical parts, controlled by a microcircuit. Sensitive to voltage changes. | POS-3, PTC-15, IR21 |
How to determine the type of your relay?
- 🔍 By appearance: tablet - round, rectangular - flat with terminals, electronic - compact, often with a radiator.
- 📜 By marking: indicated on the body type (for example,
DCL-123orRCO-805). - 🔧 By compressor: on the compressor sticker there is information about the type of relay (for example,
Relay: RCO-407).
⚠️ Attention: In refrigerators with a system No Frost often used combined relay, which controls both the compressor and the fan. Replacing it requires precise selection according to the refrigerator model - universal analogues will not work!
What Is it dangerous to install the wrong type of relay?
If you install an electronic relay instead of a mechanical one (or vice versa), the compressor may:
1) Not start at all (the relay will not be able to close the starting winding).
2) Overheat and burn out (wrong current in windings).
3) Work in jerks, which will lead to pressure surges in the system and leakage of freon.
In the worst case, the compressor will need to be replaced (from 8,000 rubles).
How to select a relay according to parameters: current, power, brand compressor
Even if you have determined the type of relay, this is not enough. You need to select a model based on four key parameters:
- Rated current (
Rated Current):Indicated on the relay body in amperes (for example,
4.5A). Must match with compressor current (see sticker on it). Permissible deviation: ±0.5 A. If you install a relay with a lower current, it will burn out; with a large one - the compressor will not start. - Compressor power:
For example, for a compressor Danfoss NL6 (120 W) a relay is suitable
RCO-407, and for Secop LA120 (180 W) -RCO-805. The power is indicated on the compressor nameplate. - Refrigerant type:
Relays for R134a and R600a may differ! For example, compressors running on R600a (isobutane) require a relay with a higher starting current.
- Climate class:
For refrigerators operating at temperatures below +10°C (for example, in an unheated garage), you need a relay with lower response threshold (indicated in the characteristics as
Min Ambient Temp).
Critical error: ignore the brand of compressor. For example, a relay for Embraco EG80 will not be suitable for Matsushita CNV85, even if the current and power are the same. Manufacturers use different start-up algorithms!
Where to find the parameters?
- 📋 On compressor sticker (glued to the body). Look for the lines:
Model,Power,Current,Gas. - 🔧 In refrigerator passport (section "Technical Specifications").
- 🌍 On manufacturer's website according to the refrigerator model (for example, for Indesit BIAA 13 a relay is suitable
V2R4).
Compatibility table of relays and compressors of popular brands
Below is the current data on the compatibility of relays and compressors for refrigerators manufactured after 2010. For older models (before the 2000s), the parameters may differ.
| Refrigerator brand | Compressor model | Type relay | Relay article number | Current (A) |
|---|---|---|---|---|
| Atlant, Stinol | Danfoss NL/NLX 6-12 | Rectangular (RCO) | RCO-407, RCO-410 | 4.5–5.2 |
| Indesit, Ariston | Secop (DWM) LA80-100 | Rectangular (RCO) | V2R4, 2RCS-015 | 5.0–6.0 |
| LG, Samsung (inverter) | LG Inverter L123X | Electronic (PTC) | POS-3, PTC-15 | 3.0–4.0 |
| Biryusa, ZIL (Soviet) | KV-8, KV-12 | Tablet (DCL) | RTK-1, DCL-08A | 2.5–3.5 |
| Beko, Vestfrost | Embraco EG80-120 | Rectangular (RCO) | RCO-805, 3RCS-022 | 6.5–7.5 |
⚠️ Attention: For refrigerators No Frost with two compressors (for example, Samsung RB37J5240) it is required two relays —separately for the main one and for the fan. Their article numbers may differ!
If your model is not in the table, use the universal rule:
- Find lines on the compressor
ModelandType(for example,Embraco EG120HL). - Enter this model into a search engine with the request "
starting relay for [compressor model]". - Check that the current and power match the parameters on the sticker.
Where to buy a starting relay and how to avoid fakes
Relays are sold in four types of points:
- 🛒 Service centers (original parts, but expensive).
- 🌍 Online stores (AliExpress, I take, Yandex Market -cheaper, but the risk of counterfeiting).
- 🏬 Spare parts stores (for example, 220 Volt, Chip and Dip).
- 🔧 Used markets (cheap, but without a guarantee).
How to distinguish the original from the fake?
- 🔍 Frame: the original has matte plastic, without burrs. The fakes often shine and have uneven seams.
- 📜 Marking: on the original the inscriptions are clear, without errors. For fakes, the letters may be blurred or with typos (for example,
RCO-40instead ofRCO-407). - 🔧 Contact: on the original relay terminals made of brass, while a fake is made of steel (magnetic).
- 💰 Price: if the relay costs 2-3 times cheaper than the average market price (for example,
RCO-407for 200 rubles instead of 600-800), it is a fake.
💡 Tip: Before buying, check the reviews about the seller. On AliExpress look for stores with a rating of at least 98% and the number of orders >1000. In offline stores, ask for a certificate of conformity.
Step-by-step replacement of the starting relay: instructions with photos
To replace the relay you will need:
- A Phillips screwdriver (or flat, depending on the mounting).
- Multimeter (for checking after installation).
- Pliers (if the terminals are oxidized).
- Alcohol and cotton swabs (for cleaning contacts).
Step 1. Disconnecting the refrigerator
Unplug from the socket and wait until the capacitors are discharged (5-10 minutes). If the refrigerator is electronically controlled, unplug it for 15 minutes to reset the settings.
Step 2. Removing the old relay
- Remove the back cover of the refrigerator (if it has one) yes).
- Find the compressor - it is a black cylinder with tubes.
- The relay is attached to the compressor on the top or side. Disconnect it by pulling up (sometimes you need to press the latch or unscrew the screw).
- Disconnect the wires from the relay terminals. Remember or take a photo of their location!
Step 3. Installing a new relay
- Clean the compressor contacts with alcohol.
- Connect the wires to the new relay in the same order as on the old one.
- Install the relay on compressor until it clicks or secure with a screw.
- Check that the relay is seated tightly, without play.
Step 4. Check operation
- Connect the refrigerator to the network.
- Listen: there should be one click (the relay has worked) and compressor humming.
- Check the voltage at the relay terminals with a multimeter (should be ~ 220 V).
- Touch the relay body after 10 minutes of operation - it should be warm, but not hot.
⚠️ Attention: If after replacing the relay the compressor does not start and the relay clicks every 5-10 seconds, the problem may be:
- A jammed compressor (check if the shaft rotates manually).
- Faulty thermostat (check it with a multimeter).
- Low voltage in the network (must be at least 200 V).
What to do if the relay does not fit?
If the new relay does not start the compressor, but the parameters are the same:
1. Check the polarity of the wires (the starting and operating ones may be reversed). windings).
2. Make sure that the relay is designed for your type of refrigerant (for example, for R600a you need a relay marked For R600).
3. Try to start the compressor directly (without a relay) by applying voltage to the working winding. If it does not start, the problem is in it, not in relay.
Common mistakes when replacing a relay and how to avoid them
Even experienced technicians sometimes make mistakes that lead to repeated breakdowns. Here are the most common ones:
- Ignoring the compressor brand:
As mentioned earlier, the relay for Danfoss is not suitable for Embraco, even if the current is the same. Always check the documentation.
- Switched wires:
If you swap the starting and operating winding wires, the compressor will hum, but not will start. There is usually a marking on the relay terminals:
S— starting winding (Start).R— operating winding (Run).C— common contact (Common).
Oxidized or loose terminals lead to heating and burning of the relay. Clean the contacts with alcohol and check the reliability of the fastening.
A relay for 220 V will not work in a 110 V network (and vice versa) In Russia, the standard is 220 V, but in some imported refrigerators (for example, Japanese) the relay may be rated at 100–120 V.
If the relay body touches the metal parts of the refrigerator and there is no grounding, a breakdown is possible on the body. Always check the insulation of the wires.
💡 Useful life hack: After replacing the relay, take a photo of the connection and save it in your phone. will help with future repairs.
⚠️ Attention: If after replacing the relay the refrigerator works, but after a few days the problem returns, check:
- The voltage in the network (it may be fluctuating, and you need to stabilizer).
- Condition of the starting capacitor (it may be faulty).
- Room temperature (if below +10°C, the relay may not work).
FAQ: Answers to frequently asked questions
Can the start relay be repaired or just replaced?
Mechanical relays (tablets and some RCO) can be repaired: clean the contacts, replace the bimetallic strip or solder the wires. Electronic relays (PTC, POS) are not repairable - they are only replaced.
If you have no experience in soldering or working with small parts, it is easier to buy a new relay (the cost of repairs is often comparable to the price of a new part).
How to test a relay without a multimeter?
Can be used 220 V light bulb (for example, from a table lamp):
- Connect the light bulb in series with the relay coil.
- Apply 220 V voltage to the circuit.
- If the light bulb comes on and off (or blinks), the relay is working properly. If it doesn’t light up or lights up constantly, the relay is faulty.
⚠️ Caution! Working with 220 V voltage is dangerous. Use insulated wires and do not touch the bare contacts.
What to do if there is no exact analogue of the relay?
In this case:
- Choose a relay with same current i type (RCO, DCL or PTC).
- Make sure it is suitable for your refrigerant (R134a or R600a).
- Check compatibility using the compressor manufacturer's tables (for example, on the website Danfoss or Embraco).
If you are not sure, contact the service center with a photo of the compressor sticker. They will select the closest analogue.
How much does it cost to replace a relay in the service?
The cost depends on the region and type of relay:
- Replacement of a tablet relay - 1,000–1,500 rubles.
- Replacement of RCO/PTC relay - 1 500–2,500 rubles.
- Diagnostics + replacement — 2,000–3,000 rubles.
Price of a new relay:
- Original — 800–2,500 rubles.
- Analog - 300–1,200 rubles.
💡 Tip: If the refrigerator is under warranty, do not repair it yourself - this will void the warranty. Contact an authorized service.
Can I use a relay from another refrigerator?
It is possible, but only if:
- The relay type is the same (RCO, DCL or PTC).
- The current and power are identical (permissible deviation: ±0.5 A).
- The relay is designed for the same refrigerant.
For example, a relay from Indesit with a compressor Secop LA100 is suitable for Beko with the same compressor. But a relay from Atlanta is not suitable for LG, even if they are similar in appearance.