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Joined: 8/25/2010(UTC)
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Background: About 6 months ago, My Kenmore electric dryer stopped heating. The drum turned fine, just no heat. I checked all the thermostats, the thermal fuse, and the heating element - all were fine. Voltage at the source was fine too. I came to the conclusion that it must be the control board. I replaced the board and all was well. While replacing the board, I replaced the thermistor as well since I did not really understand why the resistance was so high and assumed it was bad too.
Fast forward to this weekend....all is no longer well. Same problem - drum turning, no heat. All parts mentioned above tested same. Test shows the thermistor (thermostat next to the thermal fuse on the fan housing) at over 9k ohms. The leads are disconnected and part on bench for test. The reading decreases as it gets warmer just from holding it.
Is the thermistor just another thermostat? Should it show such high resistance at room temperature and decrease resistance when heat is applied? Also, should the control board go bad after just six months?
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Rank: Advanced Member
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Here is the tech sheet http://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%203979705.pdf[COLOR="Blue"]Is the thermistor just another thermostat?[/COLOR] Not really. Thermostat open/close contacts at a certain temperature, thermistors change resistance with temperature. [COLOR="Blue"] Should it show such high resistance at room temperature and decrease resistance when heat is applied?[/COLOR] Take a look at the tech sheet. [COLOR="Blue"]Also, should the control board go bad after just six months?[/COLOR] No it should not but you cannot assume that the board is gone without more testing. I am assuming that the heating coil, high limit and thermal cut-off all check out OK. You could try swapping the motor and heater relays, I believe they are the same but check this before swapping them. If the unit now does not run then odds are the relay is toast. If that does nothing check that the heater relay is getting power when it should. I do not know what it should be and could not find that info in the tech sheet. I would start with looking for 120 AC then try a couple DC scales. Since it shows a high and low to the coil I have a feeling it will be DC. |
THIS FORUM IS DEAD!!!!!!! |
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Rank: Member
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Joined: 8/25/2010(UTC)
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Thanks for the info and the link to the tech sheet is just what I needed! I'll post what it was when I get it done.
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