Sensor-Fuse-Bimetal: Refrigerator NTC and Bimetal Guide

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Introduction: What Are Sensors, Fuses and Bimetals?

The unseen heroes of refrigerator electronics are sensors, thermal fuses and bimetal thermostats. Working together, these three components measure the internal temperature of your refrigerator, manage the defrost cycle and safely cut the circuit in case of overheating. Whether the refrigerant evaporates at the right temperature, whether the frost building up on the evaporator is melted in time and whether the compressor avoids running unnecessarily all depend entirely on these small but critical parts. As Yedepa.com, in the Sensor-Fuse-Bimetal category we bring together under one roof the original and OEM-equivalent parts that technicians and service centers need every day.

In this guide we will cover the temperature control elements that fail most often in Ariston, Bosch, Arçelik, Beko, LG and Samsung refrigerators, their operating principle, the reference numbers you need to check to choose the right part, and the typical failure scenarios encountered in the field. Our aim is to enable both professional HVAC technicians and authorized service centers to find the right product at a glance.

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Technical Details and Operating Principle

In a modern No-Frost refrigerator, the refrigeration cycle is managed by three different control layers. The first is the NTC type temperature sensor; the second is the bimetal thermostat; and the third is the thermal fuse. Although all three serve the same purpose, their behavior differs:

NTC sensor: A resistor with a negative temperature coefficient. Its resistance increases as the temperature falls and decreases as it rises. It tells the main board what temperature the refrigerator is at. It typically gives values in the range of 5 kΩ to 30 kΩ between -25°C and +25°C.
Bimetal thermostat: Consists of two metals with different expansion coefficients joined together. At a certain threshold temperature it bends and opens or closes the contact. It physically controls whether the Defrost heater switches on or not.
Thermal fuse: A single-use safety element. If the bimetal fails and the defrost heater heats continuously, the fuse melts and cuts the circuit permanently. It prevents the plastic body from melting and a refrigerator fire.

The main board reads the resistance value from the NTC and decides when the fan motor, compressor and defrost heater will operate. The bimetal and fuse, on the other hand, are mounted in physical contact with the evaporator block where the heater is located. All parts sold at Yedepa.com are supplied with the original connector and resistance values in line with this three-layer protection logic.

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Types and Models

The temperature control elements frequently encountered in the sector fall into three main groups. Determining which group you need is the first step in choosing the right part.

Defrost Bimetal Thermostats: There are models coded by their opening temperature, such as ML-80, L47, L55 and L70. In the Ariston, Indesit and Hotpoint group, reference 196986 is very common.
NTC Type Temperature Sensors: In the Bosch group, sensors with codes 619691 and 609193 measure cabinet and evaporator temperature. On the Arçelik-Beko side, 4-pole models such as 4298520185 read both the fresh food and freezer compartments from a single connector.
Defrost Sensors and Thermostops: The LG 6615JB2005A defrost sensor and the Samsung DA47-10150F thermostop are hybrid solutions in which the thermal fuse and the bimetal are combined in the same body.

Differences between manufacturers directly affect the connection type, wire color and threshold temperature. If you fit a bimetal with the wrong temperature value, defrost either never starts or the heater stays on constantly; in both cases the customer will call you again soon.

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Which Model to Choose? Decision Guide

The steps to follow to choose the right part are:

Read the refrigerator's brand and model label on the inner wall of the cabinet. The "Type" or "Mod." code on the label is important.
Note the original code on the old part. Numbers such as 196986, 4328840485, 619691 and DA47-10150F should be used as the reference.
Check the number of pins on the cable connector. 2-pin, 3-pin and 4-pin variants are not interchangeable.
Verify the bimetal opening temperature. There are different values such as -7°C, -5°C, +5°C and +13°C.
Measure the NTC resistance value at a room temperature of 25°C. Most Bosch models give approximately 5 kΩ at 25°C.

When you apply these five steps, you reduce the risk of the wrong part to almost zero. In the Yedepa.com product descriptions, we give the list of compatible models and reference codes in detail; this allows you to verify from a mobile device even in a garage.

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Sensor-Fuse-Bimetal Products Available at Yedepa.com

Some of the most preferred models in our category, ready in our stock, are:

Ariston - Indesit Refrigerator Bimetal Thermostat (Original) — 4 USD. The standard defrost bimetal of the Ariston and Indesit series.
Ariston - Indesit Refrigerator Bimetal Thermostat 196986 (Original) — 4 USD. Original reference 196986, Hotpoint compatible.
Refrigerator Bimetal Thermostat - 196986 Compatible with Ariston, Indesit, Hotpoint — 3 USD. OEM equivalent performing the same function; a budget-friendly solution.
ML-80 Refrigerator Bimetal Defrost Thermostat — 3 USD. Universal ML series, used in multi-brand No-Frost refrigerators.
Bosch Refrigerator NTC Temperature Sensor 619691 — 2 USD. Cabinet sensor of the Bosch and Siemens group.
Arçelik - Beko Refrigerator Temperature Sensor (4-Pole) 4298520185 — 2 USD. 4-pole hybrid sensor.
Arçelik Refrigerator Bimetal Thermostat 4328840485 — 2 USD. Original-coded bimetal used in Arçelik's latest-generation No-Frost refrigerators.
LG 6615JB2005A Refrigerator Defrost Sensor — 2 USD. Defrost control element of the LG side-by-side and combi series.
Bosch 609193 Refrigerator Evaporator Temperature Sensor — 2 USD. NTC mounted directly on the evaporator.
Samsung Refrigerator Thermostop DA47-10150F — 2 USD. Samsung's bimetal + thermal fuse combination.

All products are shipped from our stock; because original and equivalent options are shown in the same list, the technician's decision is made easier.

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Professional Selection Criteria

For an HVAC technician or authorized service technician, price alone is not enough when choosing a part. In the table below you can find a technical comparison of the best-selling products in our category:

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Product	Brand	Type	Price
196986 Bimetal Original	Ariston	Defrost Bimetal	4 USD
196986 Bimetal Equivalent	OEM	Defrost Bimetal	3 USD
ML-80 Bimetal	OEM	Universal Bimetal	3 USD
NTC 619691	Bosch	Cabinet Sensor	2 USD
NTC 609193	Bosch	Evaporator Sensor	2 USD
4298520185 Sensor	Arçelik/Beko	4-Pole Hybrid	2 USD
4328840485 Bimetal	Arçelik	Defrost Bimetal	2 USD
6615JB2005A	LG	Defrost Sensor	2 USD
DA47-10150F Thermostop	Samsung	Bimetal + Fuse	2 USD

For customers with high warranty demands, preferring Ariston and Arçelik original-coded parts provides long-term confidence. In jobs where the service budget is dominant, OEM equivalents are a completely safe alternative as long as they are produced with the correct resistance values and threshold temperature.

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Common Failures in the Field

According to our years of field experience, the following failures are seen most often in the Sensor-Fuse-Bimetal group:

Refrigerator not cooling but the compressor is running: Usually the evaporator has iced up completely. The cause is the bimetal thermostat not opening or the NTC sensor giving the wrong resistance.
Fresh food compartment too cold, freezer normal: The resistance value of the cabinet NTC sensor may have drifted. Replacing the Bosch 619691 or Arçelik 4298520185 solves the problem.
Defrost heater stays on constantly: This means the bimetal opening temperature has risen. A new bimetal with the correct threshold is essential.
Refrigerator does nothing, the fuse has blown: The thermal fuse has gone open circuit. Instead of replacing the fuse alone, replace it as a set together with the bimetal.

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Usage, Installation and Maintenance Recommendations

When you fit a new sensor or bimetal, do not neglect the following checks:

Always disconnect the refrigerator from the power before dismantling. Do not work on the board before the capacitor has discharged.
Photograph the wire colors of the old part; the pin order is especially critical on the 4-pole Arçelik 4298520185 sensor.
When mounting the bimetal on the evaporator, use the aluminum clip or the original clamp; loose contact leads to incorrect temperature readings.
After mounting the NTC sensor, measure its resistance at a room temperature of 25°C and compare it with the value on the product label.
Also check the defrost heater; to prevent the same fault from recurring, replacing it together with the bimetal is recommended.
After installation, let the refrigerator run empty for at least 24 hours and measure the set temperature values.

These steps provide a professional approach that both protects the service warranty and minimizes the likelihood of the customer calling again.

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Detailed Information by Brand

Ariston and Indesit: These two brands, part of the Whirlpool group, use the same body and the same bimetal with reference 196986. The Hotpoint series is also compatible with this part. The original starts at 4 USD, the OEM equivalent at 3 USD.

Bosch: The pair of 619691 cabinet NTC and 609193 evaporator NTC has become standard in almost the entire Bosch and Siemens group. The 2 USD price band is the most suitable option for service centers.

Arçelik and Beko: The 4-pole 4298520185 sensor and the 4328840485 defrost bimetal are the two most sought-after products in the Turkish market. As Yedepa.com, we keep these two parts in stock at all times.

LG: The 6615JB2005A defrost sensor combines defrost and thermal control in a single body, especially in the GR-B, GR-L and GS series.

Samsung: The DA47-10150F thermostop is standard in almost all French-door and side-by-side models. With its integrated bimetal + thermal fuse structure, it solves two separate part replacements in a single swap.

OEM Equivalent: Our equivalent portfolio, led by the ML-80 universal bimetal, is an ideal alternative for technicians looking for economical service solutions.

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Frequently Asked Questions (FAQ)

1. Are a bimetal thermostat and a thermal fuse the same thing?
No. A bimetal is a reusable switch that opens and closes at a certain temperature. A thermal fuse is single-use and cuts the circuit permanently when it melts. In modern models the two are combined in a single body.

2. How do I know if the NTC sensor is faulty?
Measure its resistance with a multimeter. If at a room temperature of 25°C it gives a value outside ±10% of the manufacturer's label, the sensor is faulty.

3. Should I choose original or equivalent at Yedepa.com?
For appliances still under warranty choose original; for post-warranty service, OEM equivalent can be chosen. Both options are in our stock.

4. Which models does the Ariston 196986 bimetal fit?
It is standard in the vast majority of Ariston, Indesit and Hotpoint No-Frost series. You can find the list of compatible models in the product description.

5. Do you ship on the same day?
As Yedepa.com, we strive to hand in-stock products over to the courier on the same business day for orders received by the specified times of the day; the exact delivery time varies depending on the courier company.

6. It still ices up after replacing the bimetal, why?
The defrost heater, the defrost timer on the main board or the NTC sensor may also be faulty. Instead of replacing a single part, carry out a three-way check.

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Conclusion and Yedepa Advantages

The sensor, fuse and bimetal thermostat form the invisible nervous system of the refrigerator. If this trio does not work properly, even the most expensive parts are strained for nothing. Choosing the right part with the right reference is the most important step in protecting both customer satisfaction and the service's reputation. As Yedepa.com, we have brought together all Ariston, Bosch, Arçelik, Beko, LG, Samsung and OEM-equivalent products under a single catalog. From 196986 to 4328840485, from DA47-10150F to 6615JB2005A, we keep in stock the codes most needed in the field.

The advantages Yedepa.com offers technicians and service companies are:

The ability to compare original and OEM-equivalent options side by side.
Clear listing of the brands, models and reference codes each product is compatible with.
Professional B2B price advantage and regular service discounts.
Real technical support via WhatsApp and phone; part verification before ordering.
Safe shipping to every part of Turkey thanks to a fast supply network.

If you want to find the right bimetal, the right sensor and the right fuse with a single click, the Yedepa.com Sensor-Fuse-Bimetal category takes you to the solution by the shortest route.