Part 2 Fridge warm freezer cold how to check the components and repair

by / Tuesday, 09 August 2016 / Published in Fridge & Freezer

Part 2 find the fault with fridge freezer using our data logger and replace the faulty part

Finding the faults with fridge freezers has never been so easy how to check Ntc sensors, thermal fuse and defrost elements on fridge freezers

There are 3 main types of defrosts

  1. mechanical defrost timer (this is normally set to a time period. Example every 12 hours a defrost will take place for 15 minutes)
  2. pcb type set on a variation between temperature of evaporator (matrix) and compressor run time.
  3. pcb thats sets defrost only on run time of compressor.


What The Automatic Defrost Cycle Does on this Samsung fridge freezer
Automatic Defrost Cycle

In units with multiple evaporators, automatic defrost operates on both evaporators individually. An evaporator has a heating element that melts any accumulated frost or ice. Thermal sensors located around the evaporators send information to the main processor. This information determines when the heater will begin defrosting the evaporator.

After the initial power up, the first defrost cycle normally occurs after 4 hours of compressor run time. After that, the minimum and maximum times between cycles is 6 to 11 hours for the refrigerator and 12 to 22 hours for the freezer, respectively, for single evaporator models. For dual evaporator models with Twin Cooling, the intervals are 6 to 8 hours for the refrigerator and 12 to 16 hours for the freezer.

Thermal fuse can be checked using continuity with a multimeter. 

Ntc sensors can be checked using ohlms with a multimeter. 

The sensor has a reference impedance of 5K Ohms at 25C. Impedance goes up when temperature goes down. At room temperature the sensor should show between 4 and ten Ohms. The chart below shows impedance values for the 502AT in function of temperature (in the middle column).

The defrost heating elements can be checked using ohm's law.

here is a rough calculation i did on the element.

V = 240 volts
R = 233.3 ohm’s
240/233.3 = 1.028amp
V*amps = watts
240*1.028=246.89 watts

so this element is 250 watts thereabouts

using ohm's law calculate Fridge freezer defrost elements




Our Fridge freezer data loggers

  1. record the room temperature.
  2. record the fridge  temperature.
  3. record the freezer  temperature.
  4. record the wattage (amperage) so you can see when the motor (compressor) is running or defrost element etc.
  5. transmits and record data to graph for months at a time if need.
  6. connect to any location with wi-fi so you can veiw data any where with web access in the world.
  7. can have alarms built in to send you text warnings that a unit is too warm or too cold.

If you need more info on our system please contact us

How to check for fault with a thermal fuse

How to check for a fault with Ntc sensor


How to check for fault with a defrost heater element


24 Responses to “Part 2 Fridge warm freezer cold how to check the components and repair”

  1. mike kaminski says : Reply

    GREATvido can you point me wher i can get a data loger like the one that you use for my shop

  2. luciano stelitano says : Reply

    hello i have the problem whit frigo samsung SR-648-EV ..
    the refrigeretor defrost no working.

    i have ice around fan . the fan work!

    into pins heater refrigerator defrost (pin whait end black non have corrent!
    whot is the problem?

    Thank luciano


  3. mark christopherson says : Reply

    I have Zannusi 70/30 fridge/freezer no ice build up fan working no blokage whatwould be the problem
    thanks Paul

  4. mark christopherson says : Reply

    sorry the fridge is not getting cold 70/30 fridge freezer zannusi fan is working no blokages no ice build up
    thanks paul

  5. Behnam Ahmadzadeh says : Reply

    My SR-L629EV Samsung REFRIGERATOR is working when the first time I connect it to electricity after 3 or 4 cycle refrigerator fan and compressor turn off and the degree is locked on the last degree which I set it up (F=-18 & R=1)and won’t turn on until I unplug the cable and replug it to electricity.
    I changed the whole capacitors on board and one regulator and another transistor and compressor relay on board but it continues the problem.
    where the problem exactly is?
    I am a Ph.D. student and I really have the economic problem, due to this I can not ask repair service to solve the problem, I hope you can help me with the problem.

    Great thanks

  6. Emmanuel says : Reply

    Fantastic video you have got there on “Part 2 Fridge warm freezer cold how to check the components and repair”…. but the thing is that i have the exact same refrigerator you just worked on but the issue is that its not coming up , the compressor has a faint humming sound from it internal motor i guess and the top fridge light is on help pls i need help to rectify this myself through ur help

  7. Emmanuel says : Reply

    Fantastic video you have got there on “Part 2 Samsung Fridge freezer faults Testing Ntc,Element, Thermal fuse and replacing parts”, but the thing is that i have the exact same refrigerator you just worked on but the issue is that its not coming up , the compressor has a faint humming sound from it internal motor i guess and the top fridge light is on help pls

  8. SAM ELFAR says : Reply

    do you have help on lg french door fridge #LFX25978ST00 onhow to replace freezer sensor

  9. Pandian says : Reply

    Could u pls send the samsung refrigerator error code list
    Samsung dd frige RT29hajyasa/TL/2014

  10. Florin says : Reply

    Hi, I have a samsung fridge freezer american style, RS53K4400BC, there is no power , no display, no lights , there is power going in to the pcbs but that is it , don t know if is the main board because I don t know what output curent it needs to give. Any ideas of what oder tests I can do just using a multimeter ? I didn’t do any resitance checks because I was afraid to damage the bord . Thank you.

  11. Armani says : Reply


    Recently my fridge had a defrosting problem, the evaporator was covered with ice, so I had the thermostat replaced. It came back to normal again, the coolness in the freezer is getting along well, but the problem is, when each time the defrosting completed a cycle, I had to manually switched off the main power and turned back on again, failing so, the freezer fails to get cold air.

    Please advice, may I know is this due to the blown thermal fuse?

    Thank you for your advice

    Best wishes,
    Armani Tang

  12. Michael smith says : Reply

    Is it still possible to get a thermal fuse kit for a Samsung twin cooler American style fridge. RSE8DZAS1.

  13. Michael smith says : Reply

    Do you know anyone who sells them.

  14. Gordon Baidoo says : Reply

    I really like the video.. Very educative.. I have exactly same refrigerator in the video but finding it difficult to come out the model number to order the faulty parts…After going through the test on my refrigerator with the help of the video, I realised the defrost heater and the thermal fuse has gone bad and would kindly need to replace it… I only have to order since I can’t get one in Ghana here… Can you please be of a help to place my order…Thank you.

    Kindest regards.

  15. Emile Bester says : Reply

    Hi Paul,

    Thanks for your video, great stuff.
    I’ve followed all the steps and it seems everything is working, except, I don’t know if the fan is working, how would I know without connecting it to power? Can a Multimeter tell me?

    Thanks again for all your work.

    Regards, Emile

  16. esna says : Reply

    Hi there, I found the eBay shop from your YouTUbe clip and wondering if you can please spot the problem of my
    Samsung Fridge-Freezer_RL39WBSW1-XEU_2004

    Initially the fridge started to do the same as the fridge and froze everything inside. I opened it and measured the sensor’s resistance etc as you mentioned. But when I put everything back it started normally and a few seconds later the Error code “Rd”appeared and it stopped working. According to the web this is related to the magnet sensor problem of the Fridge spinning gate. I checked and found they work correctly.

    I guess some sensors are not working properly but unable to spot the right one to order.


  17. Haddon says : Reply

    If my thermal fuse is stuck “on” will it interfere with the defrost operation? Samsung RL38SBSW

    • if any component in the default system is not working correctly it will cause a problem with the defrost operation. The defrost system normally only comes on once every 24 hours depending on the model of machine or when certain temperatures are reached the defrost normally is only activated for a few minutes. If it isn’t unable to melt the ice in that period of time it will build up over a period of time therefore causing problems.

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