How to connect a time relay to the refrigerator: a step-by-step guide with diagrams

Connecting a time relay to a refrigerator is a task that solves several problems at once: it saves energy, extends the life of the compressor and allows automation defrosting. But improper installation can lead to equipment breakdown or even fire. This article will help you figure out how to choose time relay, connect it to refrigerators of different brands (Indesit, Samsung, Atlant etc.), set up operating cycles and avoid common mistakes.

We will analyze in detail the connection diagrams for single-phase and three-phase compressors, explain how to calculate optimal work/rest time, and we will provide unique data on relay compatibility with popular refrigerator models of 2020–2026. You will also learn what tools you will need, how to check the functionality of the system after installation and what to do if the relay does not work.

Why does a refrigerator need a time relay: 5 practical reasons

Many users make the mistake of They believe that a time relay is only needed for defrosting. In fact, its functions are much wider:

• ⏱️ Electricity savings up to 30% due to optimization of compressor operating cycles (especially important for older models of refrigerators of class D and below).
• ❄️ Automatic defrosting without user intervention - the relay can be programmed to turn off the refrigerator for 1-2 hours once a day.
• 🔧 Compressor protection from overheating: forced pauses in operation prevent wear of parts.
• 📅 Convenience for seasonal use (for example, in the country): the refrigerator will only turn on at specified times clock.
• 🚨 Emergency shutdown during power surges (if the relay has the function U-min/U-max).

It is important to understand that the time relay does not replace the thermostat - it only complements it. If your refrigerator is already equipped with a system No Frost, connecting a relay may be redundant (but not harmful!). But for models with manual defrosting (Atlant MHM 1705, Biryusa 140), this solution greatly simplifies maintenance.

Which time relay to choose: comparison of types and models

All time relays are divided into mechanical and electronic. The first ones are cheaper (from 500 rubles) and easier to configure, but less accurate. The second ones are more expensive (from 1,500 rubles), but they allow you to program complex cycles and have protection against power surges. Let's consider the key parameters. choice:

For refrigerators with a power of up to 200 W, any relay with a load current of 6 A is suitable. If the compressor is three-phase (found in industrial models), you will need a specialized relay, for example, Finder 80.01. Please note installation type: the relay can be installed on a DIN rail, in a socket or directly in the gap. circuits.

⚠️ Attention: If your refrigerator is equipped with an inverter compressor (LG Inverter Linear, Samsung Digital Inverter), connecting a time relay may disrupt its operation. In such models, control is carried out by an electronic unit, and an external relay will create a command conflict.

Preparing for connection: tools and safety measures

Before starting work, make sure that you have everything you need:

Phillips and flathead screwdriver

Voltage indicator (tester)

Pliers and stripper for wires

Heat shrink tube or electrical tape

Soldering iron (for reliable connection of wires)

Terminal blocks (if the relay is mounted in an open circuit)

Multimeter for testing contacts-->

Also prepare the workplace: disconnect the refrigerator from the network, free access to the rear panel and compressor. If the model is built-in (Liebherr IK 3560), you may need to dismantle the facade.

General safety rules:

• 🔌 Do not connect the relay. to a 220V network, if you are not sure of the correctness of the circuit.
• 🧤 Use dielectric gloves when working with live wires.
• 🔥 Do not mount the relay near the heating elements of the refrigerator.

⚠️ Attention: If your refrigerator is connected via an RCD (protective shutdown device), after installing the relay, a false shutdown may occur. This is due to the starting currents of the compressor. The solution is to use a relay with a soft start or increase the rating of the RCD to 30 mA.

Schemes for connecting a time relay to a refrigerator

There are three main ways to connect the relay. The choice depends on the relay model and design. refrigerator:

1. Connection through a socket (the easiest way)

Suitable for a relay with a plug, for example Ferron TM16 or Theben Timer 26Diagram:

1. Insert the refrigerator plug into time relay socket.
2. Connect the relay plug to a 220V power outlet.
3. Set the timer to the desired work/rest intervals.

Advantage: does not require intervention in the electrical circuit of the refrigerator. Disadvantage: the relay takes up the socket and can. interfere.

2. Connecting to a phase wire break

A more reliable method, but requires skills in working with electrical wiring. Procedure:

1. Disconnect the refrigerator from the network and remove the back cover.
2. Find the compressor connection point. to the network wire (usually a terminal block marked L, N).
3. Disconnect the phase wire (L) and connect it to the relay contacts according to the diagram:

220V network (phase) → Contact 1 relay (NO/NC) → Contact 2 relays → Compressor (L)

For mechanical relays, use normally open contacts (NO), for electronic ones - check the documentation.

How to determine the phase wire without a tester?

If you do not have a voltage indicator, you can use the “old-fashioned” method with potatoes: cut a raw potato in half and stick two wires into it (alternately) for 5–10 seconds. A greenish spot will appear around the phase wire (starch reaction to current). The method works, but does not guarantee 100% accuracy!

3. compressor

Relevant for refrigerators with a separate starting relay (Danfoss 103N0210, Aspera R134a). In this case, the time relay is installed parallel to the starting one:

• 🔧 Connect the contacts of the time relay to the terminals M (main) and S (start) start relay.
• 🕒 Set the turn-on delay to 3-5 minutes so that the compressor has time to cool down.

For three-phase compressors (found in industrial refrigerators), the circuit becomes more complicated - you will need a relay with three pairs of contacts, for example, ABB CT-MFS.22.

Setting the time relay: optimal cycles for the refrigerator

The correct timer setting depends on the purpose of use:

1. Energy saving mode

Ideal cycle for most household refrigerators:

• ⏳ Compressor operation: 30–40 minutes.
• ⏸️ Pause: 20–30 minutes.

This mode reduces energy consumption by 15–25% without the risk of food spoilage. For freezers (Atlant M 7204-003), the pause can be increased to 40 minutes.

2. Automatic defrosting mode

For refrigerators with manual defrosting (Saratov 420, Zanussi ZRA 32100) set:

• 🕐 Shutdown time: 1-2 hours a day (preferably at night, when the room temperature is lower).
• 🌡️ Temperature in the chamber should not rise above +8°C (use a thermometer for control).

3. Compressor protection mode

If the refrigerator often turns on/off (a sign of a thermostat malfunction), the relay can be used as "insurance":

• ⚡ Minimum pause between starts: 5 minutes (for compressors Embraco EGX, Secop SC10ML).
• ⏱️ Maximum operating time without stopping: 2 hours.

In electronic relays (for example, ABB E 230), these settings are programmed through the menu. In mechanical (Elko EPM) - using rotary disks.

Typical mistakes and how to avoid them

Even experienced professionals sometimes make mistakes when connecting relays. Here are the most common ones:

1. Incorrect choice of relay contacts (using normally closed ones NC instead of normally open NO). Consequence: the refrigerator will work constantly or not turn on at all.

   Solution: always check the circuit in the instructions for the relay!

2. Ignoring starting currents. When starting, the compressor consumes 3–5 times more current than in operating mode. If the relay is not designed for such loads, the contacts may burn out.

   Solution: choose a relay with a current reserve (for example, for a 150 W compressor, take a relay for 10–16 A).

3. Setting too long pauses in defrost mode. If the refrigerator is turned off for more than 2 hours, the food in the freezer may begin to melt.

   Solution: use a thermometer to monitor the temperature inside the compartment.

4. Poor contact at the connection points of the wiresThis leads to heating. and the risk of fire.

   Solution: always check the reliability of the connections with a multimeter in the "continuity" mode.

⚠️ Attention: If, after connecting the relay, the refrigerator begins to make uncharacteristic sounds (humming, clicking), immediately disconnect it from the network! This may indicate a compressor malfunction or a short circuit in the relay circuit.

Checking operation and troubleshooting

After connecting the relay, you need to test the system:

1. Visual inspection:
   • Check that is there any sparking or heating at the junction of the wires.
   • Make sure that the relay is securely fastened (does not vibrate when the compressor is running).
2. On/off test:
   • Start the refrigerator and check if the relay operates at the specified intervals.
   • Measure the voltage at the relay output with a multimeter (should be 220V in the "ON" position).

Temperature control:

• Place the thermometer in the refrigerator compartment and check that the temperature does not go beyond +2...+8°C.

If the relay does not work:

• 🔍 Check whether voltage is supplied to the relay input (there may be a problem with the socket or surge protector).
• ⚙️ Make sure the timer is turned on (mechanical relays often have a separate switch ON/OFF).
• 📞 If the relay is electronic, try resetting to the factory ones (usually a button Reset).

To diagnose the compressor, use a tester: the resistance between the windings should be in the range of 10–40 Ohms (for exact values, see the documentation for the model).

FAQ: Frequently asked questions about connecting a time relay

Is it possible to connect a time relay to a refrigerator with a No system Frost?

Yes, but this is not always advisable. In refrigerators No Frost defrosting occurs automatically due to the fan and heating element, and the time relay can only save electricity. However, if you want to limit the operating time of the compressor (for example, in the country), the connection is possible. The main thing is not to interrupt the defrosting cycle, which usually takes 10-15 minutes every 8-12. hours.

How to calculate the optimal operating time and pauses for my refrigerator?

Use the formula:

Pause time (min) = (Operating time × Compressor power) / 100

Example: for refrigerator Atlant MXM 2835 with a 140 W compressor and an operating time of 40 minutes:

Pause time = (40 × 140) / 100 = 56 minutes.

Adjust the values depending on the room temperature (in hot weather there is a pause shorten).

Will a time relay work with an inverter compressor?

Most likely not. Inverter compressors (LG Linear, Samsung Digital Inverter) regulate the power smoothly, without completely turning off. An external time relay will conflict with their operating algorithm, which can lead to breakdown. specialized relays with support for PWM signals, but they are expensive and rarely used in everyday life.

Can a time relay be used for a freezer?

Yes, but with reservations:

• The temperature in the freezer should not rise above -10°C during pauses.
• The maximum shutdown duration is 1 hour (for chambers with a thick layer of ice, 1.5 hours are allowed).
• It is better to use a relay with a function random switching on (for example, Theben Timer 26 R) to avoid simultaneous load on network.

Is it necessary to change the relay settings depending on the season?

It is advisable. In the summer, when the room temperature is higher, the compressor needs more time to cool, so the pauses between cycles should be reduced by 20–30% in the winter (if the refrigerator is in the cold). unheated room) you can increase the pauses or completely turn off the relay if the ambient temperature is below +10°C.