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Thread: Samsung dryer not heating Please help

  1. #1

    Samsung dryer not heating Please help

    Model Number: DV42H5200EP/A3
    Brand: Samsung
    Age: 1-5 years

    My Samsung dryer is under 3 years old and does not heat. I have 120v at both legs at the dryer and 240 between both. The heating coil has 11 ohms of resistance and both thermal cutoffs have .3 ohms. The thermostat in the blower duct has 12kohms and goes up with heat from a hairdryer applied. I took the dryer apart and moved the belt switch so I could run the dryer, I checked for power at the heating element with the dryer running, red wire coming from the motor has 120, no power to the blue wire. So I replaced the main board with the relay assuming it is not switching. Still no heat and no power to the blue wire coming from the relay. I have checked resistance through this wire, reads .3 ohms. There are no fault codes, no clogged air ducts. Also if I check switched power at the relay to the blue wire I get 120 volts, but I am assuming that is coming from the supplied 120 of the heating coil from the red wire coming from the motor, because if I remove the blue wire from the heating coil I have no voltage

    Thank you for any help

  2. #2
    Doc
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    Have you checked the black wire at the relay/board back to L1 at the terminal strip ?
    I would disconnect it from the board when doing this to ensure that you are not reading an alternate circuit path.
    It should also be 0.3 ohms.
    Also with the dryer off there should be 120 volts at the black to Neutral/ground on the board.

    I am assuming that your meter has a 0.3 ohm offset since the readings that shoul be zero are .3.

  3. #3
    Quote Originally Posted by denman View Post
    Have you checked the black wire at the relay/board back to L1 at the terminal strip ?
    I would disconnect it from the board when doing this to ensure that you are not reading an alternate circuit path.
    It should also be 0.3 ohms.
    Also with the dryer off there should be 120 volts at the black to Neutral/ground on the board.

    I am assuming that your meter has a 0.3 ohm offset since the readings that shoul be zero are .3.
    I checked the wire and do have good resistance.3, and 120 volts at the black wire, unplugged at both relays. I am using a fluke88 meter and the .3 reading is because I didn't zero out the meter to make up for the small lead resistance.
    Thanks

  4. #4
    Doc
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    Is this a single or a dual element dryer?

    With the unit plugged in but Off what is the voltage at the control board black and blue wires?
    Note when they are connected to the board.
    Voltages to Neutral/ground and voltage from blue to black?
    Should be:
    Black to Neutral = 120 volts
    Blue to Neutral = 0 volts
    Black to blue = 0 volts


    What is the voltage at the same two points when the dryer is running?
    Same three readings as above.
    Black to Neutral = 120 volts
    Blue to Neutral = 120 volts
    Black to blue = 0 volts

    Note I am guessing somewhat here as I do not have a wiring diagram for this unit.

  5. #5
    I am also guessing because I don't have and cannot find a diagram. This is a single heater element dryer. The voltage readings are exactly as you describe except if I remove the blue wire from the heating coil with the dryer running I loose the 120v at that blue wire. I am assuming that the only reason I see voltage at the blue wire with it plugged in is because the 120v I get at the other red wire at the heater coming from the motor. So to try and sound less confusing, checking voltage at blue wire (switched side of the relay) with the dryer running I have 120v but if I unplug the blue wire from the heater I loose that voltage.
    sorry for any confusion
    Thanks

  6. #6
    Doc
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    with the dryer running I have 120v but if I unplug the blue wire from the heater I loose that voltage.
    I am assuming the above is measuring from the blue wire and not the connector on the board.

    I am attaching a wiring diagram which I think might be close to your unit (the second of the diagrams).

    Since the thermal cutoff, the hi-limit and the heater all measure OK I think the problem is with the heater centrifugal switch on the motor.
    You may want to check that there is continuity from the red wire on the motor to the blue wire at the control board.
    To check the centrifugal switch you could unplug the unit and short the two heavier red wires together.
    Tape them so that they cannot short to anything else or get caught in the motor etc.
    Then do a short test if you have heat then that is the problem.
    Do not let it run very long as you probably will not get a perfect short so the connection will heat up if left on for long.

  7. #7
    Thank you for the wire diagram. The last one on the bottom is the correct diagram. At the centrifugal switch I have 120v coming in at #1 and 120v coming out at #2 with the dryer running. The centrifugal switch is working.
    At wht(1p) pin 2 to the heater 32-1 I have .9 ohms resistance ,that's going through both high and low limit cut offs. At pin 1 of wht(1p) I have 120volts. The motor runs with no issues but I still checked all wiring power and grounds with no issues .I also checked the thermistor between pins 3 and 6 at wht(7p) and read 15.15 kohms, which should be good for the ambient temp. Same connector pins 4 to 5 threw the moisture sensors reads open, .4 if I short the two together. I can see no reason why relay switch at wht(1p) is not switching power over to the blue wire at pin 2.
    Thank you

  8. #8
    Doc
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    The centrifugal switch is working.
    Seeing 120 volts at the output of the switch does not tell you that the switch is OK because:
    If the switch is OK then you. see the 120 from L2.
    If the switch is not closing then you see the 120 from L1

    One way to tell if the relay is not closing is to chewck across it (black to blue) when the unit is running.
    If OK you should see 0 volts.
    If it is not closing then you see 240 volts as 120 (L1) is on the black and 120 (L2) is on the blue.

  9. #9
    Thank you for help denman. You were correct about the centrifugal switch, I pulled the switch off the motor and took the cover off so I could check the contacts. I found one of the contacts burnt. Click image for larger version. 

Name:	centrifugal switch.jpg 
Views:	20 
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ID:	544 . I would recommend to anyone with the same issue that after checking the thermal cutoffs and the heating element to go ahead and remove the cover on the centrifugal switch to get a look at the switch contacts.
    Thanks again

  10. #10
    Doc
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    You are welcome

    Thanks for getting back to us, now when someone has a similar problem they will see what worked instead of just possible causes.

  11. #11
    Quote Originally Posted by Daveftw View Post
    Thank you for help denman. You were correct about the centrifugal switch, I pulled the switch off the motor and took the cover off so I could check the contacts. I found one of the contacts burnt. Click image for larger version. 

Name:	centrifugal switch.jpg 
Views:	20 
Size:	122.7 KB 
ID:	544 . I would recommend to anyone with the same issue that after checking the thermal cutoffs and the heating element to go ahead and remove the cover on the centrifugal switch to get a look at the switch contacts.
    Thanks again
    I'm having a similar problem, if I test this tomorrow and its the centrifugal switch how do you replace it? Is it a motor swap if this is faulty? I'm only 15 months into this dryer, would be very annoyed if it required an expensive repair so soon.

  12. #12
    Doc
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    Sometimes they can be repaired but usually you have to replace the motor.

  13. #13
    Quote Originally Posted by denman View Post
    The centrifugal switch is working.
    Seeing 120 volts at the output of the switch does not tell you that the switch is OK because:
    If the switch is OK then you. see the 120 from L2.
    If the switch is not closing then you see the 120 from L1

    One way to tell if the relay is not closing is to chewck across it (black to blue) when the unit is running.
    If OK you should see 0 volts.
    If it is not closing then you see 240 volts as 120 (L1) is on the black and 120 (L2) is on the blue.
    Having an issue with relay not closing but I have replaced the board twice. 120 on both sides of relay, 240 across when running. What could cause the relay to not close?

  14. #14
    Doc
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    Could be a bad thermistor.

  15. #15
    Quote Originally Posted by denman View Post
    Could be a bad thermistor.
    Thanks for the suggestion. Just checked the thermistor and the fuse next to it. Looks good. Still stumped.

  16. #16
    Doc
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    I am also stumped now.

    Perhaps you can find something helpful at the following site.
    https://drive.google.com/drive/folde...UZmNmdRVHNpQlU

  17. #17
    Quote Originally Posted by denman View Post
    I am also stumped now.

    Perhaps you can find something helpful at the following site.
    https://drive.google.com/drive/folde...UZmNmdRVHNpQlU
    Had an appliance repair company come look at my dryer. We tested everything in the 120/240 paths and couldn't find any problems. We verified that the relay isn't closing and tested the rest of the loop by shorting it, the heater worked with it shorted.

    They left stumped and said to replace the control/display board. Is there something on that board that can cause the relay not to close but leave everything else working fine? Not a single error code.

  18. #18
    Doc
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    I cannot say as manufacturers do not publish board schematics.

    Basically tha answer is yes as there must be an I/O chip to activate the relay coil and close the relay but I do not have info on what/where it is.

    Just very strange that this is the third board that does this.

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