Refrigerators Indesit with the system No Frost equipped with an automatic defrosting mechanism that prevents the formation of ice on the evaporator. The central element of this system is defrost relay a small but critical device that controls the defrost cycle. If the refrigerator begins to work intermittently: it does not turn off, ice freezes on the back wall or, conversely, does not cool, this relay is often the culprit.
In this article we will figure out how to independently check the defrost relay in refrigerators Indesit No Frostresorting to the services of a master. You will learn about the typical symptoms of a malfunction, step-by-step diagnostics using a multimeter, and how to replace a part if tests confirm its failure. We will pay special attention to models Indesit C 132 NF, Indesit ITF 118 and other popular series with the system Full No Frost.
Before starting repairs, make sure that the problem is in the relay, and not in the thermostat, timer or defrost heating element. To do this, just arm yourself with a multimeter, a screwdriver and patience - no special skills are required. And if you have never held a tester in your hands, don’t worry: we will explain in detail which contacts and in what mode to check.
Signs of a malfunctioning defrost relay in Indesit refrigerators
The defrost relay in the system No Frost is responsible for turning on the heating element (heating element), which melts the ice on the evaporator. If it fails, the defrosting cycle is disrupted, which leads to characteristic symptoms:
- 🔄 The refrigerator works without stopping — the compressor does not turn off, since the temperature sensor “sees” constant cold due to the icy evaporator.
- ❄️ Ice freezing on the back wall (in the freezer compartment or behind the panel in refrigerator compartment) - a sign that the heating element does not turn on.
- 🌡️ Increase in temperature in the chambers - if the ice completely blocks the evaporator, the cold stops flowing.
- 🕒 Untimely defrost cycles - for example, defrosting occurs once every day instead of 2-3 times (or does not happen at all).
- 🔊 Clicks or crackling from the control unit - may indicate burnt relay contacts.
It is important to distinguish between relay failure and malfunction defrost timer or defrost sensor (defroster). For example, if the refrigerator Indesit stops freezing, but the fan is working, the problem is most likely icing of the evaporator due to a non-working heating element. And if the compressor does not turn on at all, the culprit may be the thermostat or the start relay.
In models Indesit No Frost with electronic control (for example, Indesit BIAA 13relay defrost is often integrated into the control board. In this case, replacing it requires soldering or completely replacing the module. In mechanical systems (for example, in Indesit C 168 NF), the relay is placed separately and mounted next to the compressor or on the rear panel.
Where the defrost relay is located in the Indesit No Frost refrigerator
The location of the relay depends on the model and type of control system. In most refrigerators Indesit No Frost it can be found in the following places:
- Next to the compressor —in a metal or plastic box attached to the back wall (typical for models Indesit C 132 NF, Indesit ITF 101).
- On the control board —in refrigerators with an electronic display (for example, Indesit BIAA 13, Indesit BIA 18). The relay can be soldered or connected through a connector.
- Behind the rear panel of the freezer —in some models the relay is installed next to the defrost heating element (for example, in Indesit DF 5200).
To access the relay, follow these steps:
Unplug the refrigerator
Remove the rear protective panel (if the relay is near the compressor)
Move the refrigerator away from the wall for easy access
Have a flashlight and multimeter-->
In mechanical models, the defrost relay is often combined with defrost timer (a part with a round regulator and contacts). In electronic models, it is a small rectangular block with 3-5 terminals. If you are not sure that you have found the right part, check the photographs from the instructions for your model or look for markings (for example, D51-20, RT-2).
What does a defrost relay look like?
Usually it is a small box measuring 3x4 cm with a plastic body and metal contact legs. The manufacturer's markings (for example, Danfoss, Emerson) or an inscription can be applied to the body. "Defrost Relay". In electronic models, the relay can be soldered into the board and covered with a heat-shrinkable tube.
How to check the defrost relay with a multimeter: step-by-step instructions
To diagnose the relay you will need multimeter (even the simplest model will do) and a screwdriver. Before starting the test, be sure to turn off the refrigerator. from the mains and discharge the capacitors by shorting them with a screwdriver (if they are in the circuit).
The defrost relay has 3–5 contactswhich are responsible for:
- 🔌 Power supply (220V from the network).
- 🔥 Heating element control (defrost heater).
- ⏱️ Signal from the timer/sensor (in electronic models).
Standard test scheme:
- Relay coil continuity:
- Switch the multimeter to mode
200 Ω. - Connect the probes to the coil contacts (usually these are the leads
1and2orAandB). - The resistance should be within 50–200 OhmIf the device shows
0(short circuit) or1(break) - the relay is faulty.
- Switch the multimeter to mode
- Switch the multimeter to mode
calls(diode icon). - Ring the contacts responsible for turning on the heating element (usually
3and4In normal condition they should be open. - Apply voltage to the relay coil (for example, from a 12V power supply) - the contacts should close click. If this does not happen, the relay must be replaced.
For models with electronic control (for example, Indesit BIA 18), you may need to check the signal from the board. In this case:
- Measure the voltage between the relay power contacts (should be 220V with the refrigerator turned on).
- Check whether the control signal is coming from the board (usually 5–12V on corresponding contact).
| Relay contacts | Normal condition | Symptom of malfunction |
|---|---|---|
1–2 (coil) |
Resistance 50–200 Ohm | Open (1) or short circuit (0) |
3–4 (power contacts) |
Open without power, closed when voltage is applied to the coil | Do not respond to signal |
5 (control contact) |
Voltage 5–12V from the board | No signal or voltage is abnormal |
⚠️ Attention! In refrigerators Indesit with an inverter compressor (for example Indesit ITR 5200), the defrost relay can be combined with the control module. Self-replacement in this case requires experience in working with electronics - a soldering error can damage the entire board.
Typical malfunctions of the defrost relay and their causes
The defrost relay in refrigerators Indesit No Frost fails for several reasons. Here are the most common:
- ⚡ Power surges — lead to burnt contacts or breakdown of the coil. This is especially true for regions with an unstable network.
- 💧 Moisture ingress — condensation or water leaks from the drainage system cause corrosion of the contacts.
- 🔥 Overheating —if the relay is located next to the compressor, over time its parts are deformed.
- ⏳ Natural wear —the relay life is designed for 5–7 years of operation (about 100,000 operations).
- 🛠️ Repair errors —for example, improper soldering of contacts or the use of non-original spare parts.
In 60% of cases, the relay fails due to burning of contacts. This happens when too much current passes through them (for example, when a defrost heating element is shorted). This is visually noticeable by blackened or melted legs. In such cases, the relay must be replaced - cleaning the contacts will only give a temporary effect.
Another common problem is coil winding break. This can happen due to mechanical damage (for example, due to careless installation) or manufacturing defects. This can only be checked with a multimeter, as described above.
In electronic models Indesit (for example, Indesit BIAA 13) the relay often suffers from burnout of tracks on the board. This occurs due to overloads or poor soldering. In this case, the entire control module must be replaced, since a separate relay is not sold.
How to replace the defrost relay in an Indesit No Frost refrigerator
If the check shows that the relay is faulty, it must be replaced. In most cases, this can be done independently, without the help of a specialist. The main thing is to choose an analogue of the original part.
For replacement you will need:
- New relay (marking must match the original).
- Screwdriver (phillips or flat, depending on the model).
- Pliers or pliers (for removing terminals).
- Heat shrink tube or electrical tape (for insulating contacts).
Step-by-step instructions:
- Disconnect the refrigerator plug in the power supply and discharge the capacitors (if any).
- Remove the back panel (or the freezer panel, if the relay is there).
- Take a photo of the circuit connections relay - this will help not mix up the wires when reassembling.
- Disconnect the terminals from the relay contacts. If they are soldered, carefully unsolder them without damaging the board tracks.
- Remove the mount relay (usually 1-2 screws or a latch).
- Install a new relay, connect the terminals in accordance with the diagram.
- Check the operation of the refrigerator - after turning it on, it should start a defrost cycle (after 8-12 hours of operation).
For models with electronic control (for example, Indesit BIA 18) the process is more complicated:
- The control board is usually located under the top cover of the refrigerator.
- The relay can be soldered - replacement will require a soldering iron and solder.
- After replacement, you need to reset errors (if they were displayed on the display).
⚠️ Attention! In refrigerators Indesit with a system Full No Frost (for example, Indesit ITF 118) after replacing the relay, you may need sensor calibration. To do this, unplug the refrigerator for 10–15 minutes, then turn it on again. If the problem persists, contact the service center.
The cost of a new defrost relay for Indesit No Frost varies from 500 to 2000 rubles, depending on the model. Original parts are more expensive, but last longer. Analogues (for example, from Danfoss or Emerson) are cheaper, but may differ in characteristics. When purchasing, check compatibility with your refrigerator model.
Frequent errors in diagnostics and repairs
When independently checking and replacing the defrost relay, many make mistakes that lead to repeated breakdowns or failure of other components. Here are the most common:
- 🔌 Checking the energized relay - it is life-threatening! Always disconnect the refrigerator from the mains before work.
- 🔍 Wrong choice of multimeter mode —for example, measuring the coil resistance in voltmeter mode. This can damage the device.
- 🔧 Mixing wires when connecting a new relay. Always photograph or label the terminals before disconnecting.
- 🔥 Using a powerful soldering iron (more than 40 W) to work with the control board - this can damage the tracks.
- ❄️ Ignoring checking the defrost heating element - if the heater is burnt out, a new one the relay will quickly fail.
Another typical mistake is replace only the relay without checking the timer or defrost sensor. In the system No Frost all elements work in conjunction. For example, if the evaporator sensor is faulty, it may not send a signal to the relay and the defrost cycle will not start. Therefore, after replacing the relay, it is necessary to:
- Check the resistance defrost heating element (should be 20-40 ohms).
- Make sure that defrost timer is working properly (in mechanical models it should “tick” when you turn the handle).
- Check defrost circuit fuse (if your model has it).
If after replacing the relay the refrigerator still does not start defrosting, the problem may lie in control board. In this case, you cannot do without diagnostics at a service center.
Prevention of defrost relay breakdowns
To extend the life of the defrost relay and avoid costly repairs, follow these recommendations:
- 🔌 Use a voltage stabilizer - this will protect not only relay, but also a compressor from surges in the network.
- 🧹 Regularly clean the drainage system - blockages lead to accumulation of moisture and corrosion of contacts.
- 🌡️ Do not overload the refrigerator - excess products disrupt air circulation and increases the load on the system No Frost.
- ❄️ Defrost the refrigerator 1-2 times a yeareven if it is with No Frost. This will help remove ice that may interfere with the operation of the sensors.
- 🔧 Check the door seal - if it is worn out, warm air enters the chamber, and the defrosting system works in enhanced mode.
In models Indesit with electronic control (for example, Indesit BIAA 13) it is useful to reset the settings to factory settings once every six months. To do this:
- Disconnect the refrigerator from the network.
- Press and hold the button
Super Cool(orSuper Freeze) for 10-15 seconds. - Turn the refrigerator back on - this will reset possible errors in operation of the board.
If you live in a region with a hot climate, install the refrigerator away from heat sources (stove, radiator) and provide a gap of at least 5 cm between the back wall and the wall. Overheating accelerates the wear of the relay and other electronic components.
FAQ: Frequently asked questions about the defrost relay in Indesit No Frost refrigerators
Is it possible to repair the defrost relay or just replace it?
In most cases, the defrost relay cannot be repaired - it can only be replaced. The exception is when the problem is burnt contacts: they can be cleaned with fine sandpaper. However, such a repair will give a temporary effect (1-3 months), after which the relay will still have to be replaced.
In electronic models (for example, Indesit BIAA 13), the relay is often soldered into the board. Re-soldering is possible here, but only if you have experience working with microcircuits.
How to understand that the defrost heating element has burned out, and not the relay?
If it burns out defrost heating element, then:
- The relay clicks (triggers), but the heater does not turn on.
- When checked with a multimeter, the heating element shows a break (
1on the screen). - A thick layer of ice forms on the back wall of the freezer.
If it is faulty relaythen:
- The heating element is working (resistance 20–40 Ohms), but does not turn on.
- There is no voltage on the relay contacts or they do not close when a signal is applied.
How much does it cost to replace the defrost relay in a service center?
Replacement cost The defrost relay in the service center depends on the refrigerator model and region:
- Replacement of a separate relay (in mechanical models): 1500–3000 rubles (including the part).
- Replacement of the control board (in electronic models): 4000–8000 rubles.
- Diagnostics (if the reason is unclear): 1000–2000 rubles.
Independent replacement will only cost the cost of the part (500–2000 rubles), but requires accuracy.
Can a refrigerator work without a defrost relay?
Technically, a refrigerator Indesit No Frost will work without a defrost relay, but Only until the evaporator is covered with ice. Without regular defrosting:
- The compressor will work non-stop, trying to compensate for the lack of cold.
- The temperature in the chambers will gradually increase.
- The fan may jam due to ice.
As a result, the refrigerator will either shut down due to overheating or the compressor will fail. Therefore, it is impossible to operate equipment with a faulty defrost relay It is impossible.
Which Indesit models most often break down due to the fault of the defrost relay?
According to statistics from service centers, most often problems with the defrost relay occur in the following models:
- Indesit C 132 NF — mechanical system, the relay is located next to the compressor.
- Indesit ITF 118 — Full No Frost, the relay is integrated into the board.
- Indesit BIAA 13 — electronic control, frequent problems with soldering the relay.
- Indesit DF 5200 — the relay is located behind the freezer panel, subject to corrosion.
In these models, the defrost relay is one of the weakest points, especially when operating under unstable voltage conditions.