Yesterday, after drying one load correctly the dryer stopped heating. Everything else seems fine, just no heat
Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=MDE6800AYQ
First check the power.
The heater requires the full 240 volts.
Try flipping the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.
Check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Do this with the heater off and on.
Be careful as 240 volts is lethal !!!
If OK, the next thing to check is the heating element.
Unplug the unit.
Measure across the heater element should be around 10 ohms.
It is a good idea to disconnect one side of the heater when measuring. This ensures that you do not read an alternate/parallel circuit path.
Thermostates read 0
coil reads 12
L1 and L2 combinations are correct both at the panel and the strip
Something’s up with the rotor i wonder.
Here is a manual.
http://appliancejunk.com/forums/index.php?action=downloads;sa=downfile&id=67;t=1379757841
You will have to join the site to download the manual.
The manual is a biot confusing because it covers many units.
The wiring diagram for this unit is on page 10-27.
Check from the control board (heater output) (PU_44) to motor (1) (BK_33).
Should be 12 ohms.
If it is then the problem is either the heater relay is not closing or the centrifugal switch is not closing or you have a bad connection/wire.
Check the thermistor, should be around 10,000 ohms at room temperature,
Try running the diagnostics , page 9-12.
If all the above are OK, you could try unplugging the unit and shorting across the heater relay contacts (PU_44 to BK_43) at the control board.
Then plug the unit in and give it a try.
If you now have heat then it is probably a control board problem, either the board is not closing the heater relay or the relay contacts are shot.
If there is no heat then the probable cause is the centrifugal switch on the motor. Either the switch is shot or the mechanism that activates the switch is not working.
thanks for the help…burnt wire from the high limit to the coil insulator. Runs fine now
You are welcome.
And thanks for getting back to us. Now when others search for a similar problem they will see what actually worked instead of just suggestions about what could be the cause.
Yesterday, working with Denman, I found the problem with the dryer (MDE6800AYQ) It was a burnt wire from the hi limit switch to the heater coil insulator. So, today I did a load. The dryer temperature was too hot. Maybe there’s a reason the wire burnt. I checked the ohms across the hi-limit switch with my meter set at 200 and got a reading of 4.0, the same reading I get when I short the meter leads. Is the hi-limit switch supposed to be closed?:rolleyes:
Yes it should be closed at room temperature.
Unplug the unit and check your heating coil.
it is a good idea to disconnect at least one side of it just to be sure that you do not read an alternate/parallel circuit.
it should be around 8 to 12 ohms.
Then check from each heater connector to the case/frame both should be infinite ohms (open)
If not the coil is grounded and should be replaced.
Next would be to check the thermistor resistance.
OK I’ll do that next. The thermister is open, both hi-limit switches read 4.0 and both thermal fuses read 4.0
The coil reads as it did when I first checked it 12.3
Oh…No short indicated from coil
I just reread all the post in this thread…When I check the thermister I get an infinity read…you indicated it should read 10,000 ohms. Could this be why it overheats now that I’ve replaced the burnt wire? Do I need a new thermister?
Opps…I screwed up. Moving the tester to 20k on the ohm scale I got a reading of 5.84 so, yes 10,000 ohms resistance. So, everything checks out good to go. It just overheats
Is it too hot on all temperature settings?
You could check your exhaust temperatures, see page 9-5 in the manual.
Could be that the board is not controlling the temperature and it is being controlled by one of the high limit thermostats.
The thermostat will fail eventually as it’s contacts are not made to continually turn the heater on/off.