I have replaced thermostats, thermistors, thermal fuses several times. Dryer works fine for several cycles and stops heating. What's the problem, please.
It would be disheartening to make all those repairs and then have the same problem reappear. If you have the dryer model number and add it to this thread, it will help the expert provide a better answer. In the meantime I found a previous expert post with some other things that can go wrong if you wish to check it out. I attached the link below.
Since you indicated that you replaced the thermal fuse for a heating problem, I assume that you have a gas dryer. Check the gas supply cut-off valve to make sure that it is fully open. Make sure that you have an adequate gas supply provided to the dryer.The wiring diagram for a gas HE3 dryer is shown in the image below with the heating circuit traced in red. A number of problems could be preventing the dryer from heating. You could have a failed wiring connection, a bad heater relay on the control board, a blown thermal fuse (do to an unresolved exhaust vent restriction), a bad high limit thermostat, a defective flame sensor, a bad igniter or a problem with the motor centrifugal switch. I recommend that you check the thermal fuse first. This is the most common failure in the heating circuit of a gas dryer. If that fuse is blown again, I recommend that you carefully examine the exhaust air flow system for a clog or restriction. Also, wash the lint screen with water and a soft bristle brush. Fabric softener can build up on the lint screen and restrict exhaust air flow.You can order parts from the Sears PartsDirect website.These tips may help you resolve this dryer problem. If you have an electric dryer or need more assistance, reply with additional details and the full model number of your HE3 dryer.If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website: Sears Home Services .
Thanks for providing that model number. The control board on this dryer is shown in the second image below. The first image shows the wiring diagram for your electric dryer. I recommend that you UNPLUG the dryer and check the wiring harness connections on the control board. You could have a loose connection causing this problem. When the dryer is not heating, you may need to check the resistance of the thermistor (temperature sensor) shown in the third image. Use a volt/ohm meter that is set to the proper scale to make this check. There is a possibility that you could have a voltage problem through your house electrical system. You may need to check the voltage at the dryer outlet when the dryer is not heating. The 4th image below show how to check the dryer outlet. NOTE: Use extreme care when you make this type of live voltage check at the dryer outlet. If you are not completely confident in your technical ability to safely measure that live outlet voltage, I recommend that you have an electrician or technician check it. A problem with the heater relay, the high limit safety thermostat or the motor centrifugal switch could also cause this heating problem. I hope that this additional information helps. If you need more assistance, reply with additional details.
OK, Lyle, I now have this thing in pieces. The "tech" guy was here today and proved useless. Soooo... how do I test the control board, and what is the centrifugal switch. The thermal fuse is reading .001 on the ohm meter, the thermistor is 1., the thermostat toward the back of the heating element is 1., and the one in the front is .001. I have replaced each of these twice. Voltage to thre dryer is good, and the element is good. Where to from here. My wife is tired of line drying. Thanks
Check your settings on the meter when testing the thermistor. It should read about 10K ohms (10,000) ohms at room temperature. You may need to check that component again. You did not mention the heating element resistance. Check the resistance of that component. It should measure between 7.8 and 11.8 ohms. To test that heater relay, you will need to conduct a live voltage check when the dryer is running to see if you are getting the L1 leg of voltage out of the control board. I normally don't recommend that you conduct live voltage checks. These tests are normally conducted by a service technician. If you are completely confident that you can safely check the voltage, then you can start the dryer in a heated cycle with the bottom front service panel and heat shield in front of the heating element removed. Do not touch any wires or contacts when you are running the dryer with the internal components exposed. Check to see if the heating element is glowing. If not, check the voltage going to the heating element. You should measure around 240 volts. The wiring diagram is shown in the image below with the voltage paths to the element traced. The L1 leg is traced in red and the L2 leg is traced in green. If you are getting 240 volts then the element is bad. If you are getting only 120 volts then one of the legs is bad. Unplug the dryer immediately after this test. You can check the voltage coming directly out of the control board if necessary to see if the control board is working. The centrifugal switch is difficult to check. If you can access the motor, you can manually engage the centrifugal switch and then check for continuity (near zero ohms of resistance) through the contacts 1M and 2M on the motor. I hope that these additional tips help. Reply with additional details if you need more assistance.
Honey, I'm home. All checks out positive, except the thermal cut-off. It's reading 1 on the ohm meter. I seem to remember that not being a good sign when going through this exercise prior to one of my previous repairs. Does this narrow it down to the control board. How do I check voltage coming out. If all else checks out ok, is it safe to put it back together and order a control board. Remember, it's still in pieces, and my wife's still hanging clothes.I also noticed a substantial amt. of lint in the windings of the motor. Thanks
As long as the thermal cut-off reads close to zero ohms of resistance, it is okay. If it reads Ol (open load or infinite resistance) then it will need to be replaced. I assume that you read the proper resistance through the thermistor (10 K ohms). To check voltage coming out of the control board, you would need to unplug the red wire off of the COM connection of the heater relay on the control board (with the dryer unplugged). Tape the end of that red wire so that it does not short against the cabinet. Start the dryer in a heated cycle and check for 120 volts between the COM spade on the control board and the white neutral wire on the control board. The red wire has to be disconnected or you could read the 120 volt L2 leg through that red wire. If the control board heater relay is not closing and sending the 120 volt L1 voltage to the heating element then you will need to replace the control board. NOTE: You should only conduct this live voltage check if you are completely confident in your technical ability to safely measure it. If you need more help, reply with additional details.
Ready to buy what you need?Shop now
Still have questions?Ask us
Need expert repair service?Schedule now
“This is a great place to go for advice, especially if you're low on funds and you could resolve the problem before calling and paying a service call, if it's an easy fix. I'm glad you are there for me.”