How a NTC Sensor works on a washing machine

by / Saturday, 13 December 2014 / Published in Heating Systems, Washing machines

How a NTC Sensor works on a washing machine

 

 

 

To order your Washing machine NTC Sensors and Elements you will need your full model number. (This is normally around the washing machine door frame on a sticker)

The temperature is controlled by the PCB by means of a NTC temperature sensor incorporated in the heating
element when you test it the Resistance drops as the temperature rises.

 

Heating element (with thermal fuses)What is an NTC Sensor?
A thermistor is essentially a resistor that changes its electrical resistance at varying temperatures. The name is derived from a mix of thermal and resistor. They are used in washing machines Because their electrical resistance at various temperatures is known, it’s easy for the washing machine to monitor a thermistor and detect when certain temperatures are reached.

 

Check all connections first to the sensor and to the board they may have come loose, you are sometimes unlikely to see anything physically wrong but there might be a bad connection. Diagnosis is done by measuring the resistance with a continuity (or multi) meter. We can’t give readings for all thermistors because they vary, see my picture for an example, but you should be able to get a reading across both terminals. If it’s completely open circuit it’s likely to be faulty.NTC sensor




7 Responses to “How a NTC Sensor works on a washing machine”

  1. mary says : Reply

    my washer go into a flashing f3 and e3 won’t go to the next cycle what is wrong with it

  2. sqvery says : Reply

    If I replace the NTC with a 470R resistor. Will the machine operate normally except for heating the water?

    (This will be my second NTC failure)

  3. AMIR UBAID says : Reply

    Dear Sirs,
    my washing machine starts for few minutes then cut off the power from the main circuit, every time this happens I have to put the fuse up in the main board, it is Bosh Classixx 1200.
    I would be grateful if you advise on the possible problem.
    Cheers
    Amir

  4. Hans van Steijn says : Reply

    Thank you for the clear explanation!

  5. Alberto says : Reply

    Can I connect the 2 wires going to the NTC sensor, if my machine doesn’t even have a heating element to change the temps?

  6. Secula says : Reply

    My machine is lying about temperature. It’s probably because of energy ratings. It seems ubiquitous here in Europe, most of the manufacturers are being insincere about this parameter.

    At 90°C it washes on ~65°C.
    At 60°C it washes on ~45°C.
    At 40°C it washes on ~30°C.

    You think a resistor could be added in series with NTC to raise these temperatures? Since all other cycles can be simulated with a higher temperature one, the crucial problem is 90°C cycle. So, there could be an external switch which should add like 100-500 Ohms (depending on the NTC model used) which could make temperatures go from 70°C (which I’m guessing the temperature is near the heater) to a desired 90°C.

    What do you think about this idea?

  7. […] A faulty NTC sensor might send an incorrect high-temperature reading to the machine even when the drum is cool, preventing the door from opening. You can use a multimeter set to ohmmeter mode to determine if the NTC sensor is defective. […]

24h technical help answers

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