Starting a refrigerator engine without a starting relay is a task that is encountered when diagnosing faults or in emergency situations when the original relay has failed and there is no replacement at hand. This method is often used by craftsmen to check the performance of the compressor or in conditions where there is an urgent need to preserve products in the event of a breakdown. However connecting a compressor directly to a 220V network is fraught with risks from overheating of the windings to a short circuit, if safety precautions are not followed.
In this article we will examine three working methods starting without a relay (including the method with a button and through a capacitor), we will provide universal connection diagram for most household refrigerators, and also show how to avoid common mistakes. A video with a step-by-step process and an explanation of the physics of the compressor can be found at the end of each section. If your refrigerator is model Atlant, Indesit, Samsung or Liebherr —check the parameters of the windings before starting work: they may differ!
Why you can’t constantly operate the refrigerator without relay
The starting relay performs two critical functions:
- 🔌 Closes the starting winding for a few seconds, creating the initial torque of the rotor.
- 🔥 Protects from overheating, opening the circuit when the current exceeds (for example, if the compressor jammed).
Without a relay starting winding remains energized constantly, which leads to:
- ⚡ Increased energy consumption (up to 30–40% higher norms).
- 🔥 Overheating of the windings —after 10–15 minutes of operation, the temperature may exceed the permissible 90–100°C.
- ⚠️ Risk of interturn short circuitif the wire insulation melts.
⚠️ Attention: Modern refrigerators with inverter compressors (LG, Samsung Digital Inverter) cannot be started without a relay - their electronic boards block operation if the protection circuit is broken. Check the marking on the compressor: if there is an inscription Inverter, the method will not work.
The only justified use of direct connection is short-term diagnostics (no more than 1-2 minutes) or emergency cooling for 30-60 minutes under constant monitoring. For long-term operation, be sure to install a working relay or replace it with a universal one (for example, RBM-1 or DANFOSS 101N0010).
Preparation: tools and safety measures
Before you start work, make sure that:
- 🔌 Refrigerator is disconnected from the network (the plug is removed from the socket!).
- 🧤 On you dielectric gloves (or at least rubber household).
- 🔧 I have multimeter at hand to check the resistance of the windings.
Necessary tools:
| Tool | Purpose | Alternative |
|---|---|---|
| Screwdriver (phillips/flat) | Removing the relay cover and access to the terminals | Knife with a flat blade |
| Multimeter | Testing windings, checking resistance | Probe lamp (for checking voltage) |
| Wires with terminals female starting winding) | Connection to compressor | Flexible stranded wires with a cross section of 1.5–2.5 mm² |
| Momentary button (normally open) | For the button method (shorting the starting winding) | Screwdriver with insulated handle |
⚠️ Attention: If the compressor previously worked with starting capacitor (often found in models Stinol, Pozis), it cannot be connected directly without a capacitor - this will lead to burnout of the winding. Check for the presence of a capacitor in the circuit. (usually attached to the relay).
Before removing the relay, take a photo of its connection or draw a diagram. The compressor terminals are standard:
C(Common) — common terminal.S(Start) — starting winding.R(Run) — working winding.
Take a photo of the relay connection|
Check the resistance of the windings with a multimeter|
Prepare wires with terminals|
Provide access to a grounded socket-->
Method 1: Direct connection with a button (for diagnostics)
This method is suitable for short-term test the compressor. The essence: the working winding (R) is connected. directly to the 220V network, and the starting one (S) is closed for a few seconds through a button, simulating the operation of the relay.
Step-by-step instructions:
- Disconnect the relay from the compressor, remembering the location terminals.
- Connect the wire from the socket to the terminal
C(common terminal). - Connect the second wire of the socket to the terminal
R(working winding). - Between the terminals
CandSconnect the button without fixing. - Turn on the power and briefly (1–2 seconds) press the button. The compressor should start.
If the compressor does not start:
- 🔍 Check the resistance of the windings (normal:
R–C≈ 15–40 Ohm,S–C≈ 20–50 Ohms). - 🔌 Make sure that the voltage in the socket is not lower than 200V (the compressor may not start if there is a drawdown).
- 🔧 The shaft may be jammed - try to manually turn the rotor (through the pulley).
Socket 220V
│
├───┬───[C] (General)
│ │
│ └───[R] (Working)
│
└───[Button]───[S] (Start)
Method 2: Connection via a capacitor (for long-term operation)
This method allows you to start the compressor without the risk of burning out the windings. data-i="159">), which temporarily replaces the relay. The circuit is suitable for refrigerators 30–60 minutes without the risk of windings burning out. For this purpose it is used starting capacitor (For example, CBB61 100 uF/450V), which temporarily replaces the relay. The circuit is suitable for refrigerators Biryusa, Nord, Vestfrost and others with asynchronous compressors.
What you will need:
- 🔋 Capacitor with a capacity of 80–120 uF (voltage not lower than 400V).
- 🔌 Wires with terminals.
- 📏 Multimeter for checking the capacitance of the capacitor.
Connection diagram:
- Disconnect the relay from the compressor.
- Connect capacitor in parallel starting winding (
S–C). - Apply 220V to the terminals
R(working) andC(general). - The compressor will start automatically.
220V socket
│
├───[R] (Working)
│
└───[C]───┬───[S] (Starting)
│
└───[Capacitor]
Important: The capacitance of the capacitor is selected according to the power compressor:
| Compressor power (W) | Capacitor capacity (uF) |
|---|---|
| up to 120 | 40–60 |
| 120–180 | 80–100 |
| 180–250 | 100–120 |
⚠️ Attention: After starting, the capacitor remains under tension! Before disconnecting, discharge it by shorting the terminals with a screwdriver with an insulated handle.
What will happen if you use a capacitor of larger capacity?
Too large a capacitance will lead to overheating of the starting winding, since there will be current through it exceed nominal. In the best case, the compressor will operate with increased noise, in the worst case, it will burn out in 5–10 minutes. It is optimal to select a capacitor according to the table or calculate it using the formula: C (uF) = (2800 × P) / U²where P is the compressor power in kW, U is the voltage (220V).
Method 3: Using a universal relay (alternative)
If the original relay is burnt out, and starting without it is needed for a long time, the best option is to install universal start-up protection relay (for example, RBM-1, DANFOSS 101N0010 or TRN-2). It is suitable for 90% of household refrigerators and costs from 300 to 800 rubles.
How to connect:
- Remove the old relay, remembering the location terminals.
- Connect the wires to the new relay according to the diagram (usually it is printed on the case).
- Install the relay on the compressor and secure it with a clip.
- Check the operation of the refrigerator for 10-15 minutes (the compressor should start without humming and vibrations).
Advantages of a universal relay:
- ✅ Protection against overheating and overload.
- ✅ Compatibility with most compressors (Embraco, Secop, Matsushita).
- ✅ Long service life (5–7 years).
Connection example for a relay RBM-1:
[C] (General)───┬─── 220V socket
│
[S] (Starting)───[Relay]───┘
│
[R] (Working)───┘
Typical mistakes and how to avoid them
Even experienced technicians make mistakes when starting a compressor without a relay. Here are the most common ones:
- The terminals are mixed up
SAndR.Symptoms: the compressor hums, but does not start, or the protection in the panel is triggered.
Solution: check the resistance of the windings with a multimeter - the working one (
R–C) is always less than the starting one (S–C). - A capacitor of the wrong capacity is used.
Symptoms: the compressor is overheating or does not develop full power.
Solution: use a capacitor with the capacity indicated in the table above.
- Direct connection without a button or capacitor.
Symptoms: the compressor burns out after 5-10 minutes.
Solution: never apply 220V directly to both windings at the same time!
Additional risks:
- 🔌 Unstable voltage in the network (below 200V or higher 240V) can damage the compressor even if connected correctly.
- 🔥 Lack of grounding - if the insulation breaks down, the refrigerator body will be energized.
- ❄️ Starting at low temperatures (for example, in an unheated garage) increases the load on the windings.
Video instructions: starting the compressor without a relay
For clarity, we have selected proven videos with a step-by-step analysis of each method:
- 🎥 Method with a button (diagnostics):
The video shows how to connect a compressor Atlant via a button, including checking the windings with a multimeter. Watch on YouTube.
- 🎥 Connection via a capacitor (long-term operation):
Detailed analysis of the circuit with a capacitor for a refrigerator Indesit. The author explains how to calculate the capacity. Watch on YouTube.
- 🎥 Installing a universal relay:
Replacing a burnt-out relay on DANFOSS 101N0010 in the refrigerator Samsung. The connection and testing process is shown. Watch on YouTube.
Please note: compressors of different brands may be used in the video (Embraco, Secop, LG), but the connection principle is the same. The main thing. - correctly identify the terminals C, S i R.
FAQ: Frequently asked questions about starting without a relay
Is it possible to start an inverter compressor without a relay?
No. data-i="260">) are controlled by an electronic board that blocks operation in the absence of a signal from the relay. Direct connection to a 220V network will disable the board.LG, Samsung, Hitachi) are controlled by an electronic board that blocks operation if there is no signal from the relay. Direct connection to a 220V network will damage the board.
How long can you work without a relay?
Maximum 30-60 minutes when using a capacitor Without a capacitor (only with a button) - no more than 1-2 minutes for. diagnostics. Long-term operation without protection will lead to overheating.
How to check if the relay has burned out?
Test the relay with a multimeter in the resistance test mode:
- There should be resistance between the relay power terminals
0 Ohm(closed). - Between the power terminal and the starting winding -
∞(open).
If the relay does not click when voltage is applied - it is faulty.
What to do if the compressor does not start even with the button?
Possible reasons:
- Interturn short circuit in the windings (check the resistance).
- Shaft jamming (try turning the rotor manually).
- Insufficient voltage in the network (must be at least 200V).
- Breakage in the winding (resistance
∞).
In these cases, the compressor must be replaced.
Where to buy a universal relay or capacitor?
Parts can be found:
- In stores of spare parts for refrigerators (for example, Rembytekhnika, Cold-Service).
- On marketplaces (Wildberries, Ozon, AliExpress) - search by article numbers RBM-1, CBB61.
- In radio stores (capacitors).
The average price of a relay is 400-800 rubles, a capacitor - 100-300 rubles.