My Estate (Whirlpool) electric dryer (model tedx640jq1) will not get hot. Following the helpful troubleshooting guide on this website, I have determined:
The circuit breaker is not tripped
The dryer is getting 220 volts
Main Terminal Block is not damaged
Thermal Fuse has continuity (i.e. is good)
Heating Element appears to be good with about 10 ohms of resistance
Hi-Limit Thermostat has continuity
Thermal Fuse has continuity
Thermal Cut-Off has NO continuity and appears to be bad.
Cycling Thermostat has continuity across larger spades where red wires attach, but does not have continuity across smaller center spades where purple wires attach
It appears the “Thermal Cut-Off” needs to be replaced. But I am not sure about the Cycling Thermostat; are my measurements normal for this part?
Would the identified part(s) account for no heat in the dryer, or am I missing something?
Here are your parts. Replacement parts for WHIRLPOOL TEDX640JQ1 DRYER | AppliancePartsPros.com
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Would the identified part(s) account for no heat in the dryer, or am I missing something?[/COLOR]
You are correct that a blown (open) thermal cut-off will kill power to the heating element but there are other things that should be checked before replacing it.
See the attachment for your wiring diagram.
The cycling thermostat may be OK but I cannot be 100% sure, see Blown Thermal Cut-off below.
One set of connectors are the contacts. The other set is an internal heater. It is turned on during low heat cycles. It adds heat to the thermostat so it cycles more often and results in lower heating element output. It should measure between 5600 and 8400 ohms.
If you are using too low of a meter scale it could look like an open when in fact it is OK.
Blown Thermal Cut-off
Check the heating coil.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 10 to 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and the thermostats cannot regulate it so the thermal cut-off blows.
The hi-limit should have regulated the temperature so the fuse did not blow, that is why there is a new one with the thermal cut-off..
Note: That unless there is another problem in the unit the hi-limit should never have to open. It is just a safety device with the fuse being a backup safety device.
Just in case it is not a grounded element.
With all the below the high limit will also have to be replaced.
Check that the belt is OK.
Check the seals (drum etc) in the unit. The air is pulled over the heating coils, through the drum and pushed out the exhaust. So any large seal leak will pull in room air and the cycling thermostat on the blower will run the unit hot.
Check that the lint filter is not coated with fabric softener residue which greatly reduces air flow.
Check/clean your vent system.
Check/clean the blower wheel.
If all OK you may want to replace the cycling thermostat as it’s contacts may not be opening (welded shut) Wiring Sheet - 8528187.pdf (332.8 KB)
Cycling Thermostat - thank you for explaining how this part works. I checked the two inside connectors (of the internal heater) using a higher meter scale and got a reading of 6500 ohms. The outside connectors (of the contacts) have connectivity. Thus, it appears the cycling thermostat is good.
Heating Coil - The heating coil has 10 ohms of resistance. Checking each side of the coil to the case, reads infinity ohms (i.e. open).
The lint filter is clean and “clear” of any residue (I don’t use fabric softener). I have checked and cleaned the vent system and blower wheel. I will check the belt and drum seals next (appears to do that I come in from the front).
Thus far, it looks as if the Thermal Cut-Off is the main/most identifiable problem and needs to be replaced. And, from your last reply, it appears that the Hi-Limit Thermostat (if it had been doing its job) should have prevented the Thermal Cut-Off from going out, so the Hi-Limit Thermostat should be replace too. Is this correct?
Yes I would replace the thermal cut-off and the hi-limit (Item 6 in Section 3). They come as a set.
I would also replace the cycling thermostat (Item 24 in Section 3) since you cannot find another cause for the cut-off blowing. Could be it’s contacts are welded together or are sticking closed.
I will replace the Thermal Cut-Off and High Limit Thermostat. And, since there is not a clear, identifiable reason the Thermal Cut-Off went bad, I will replace the Cycling Thermostat too. However…
I pulled the drum and everything looks good. The felt drum seals were in good condition, but I would not go so far as to say they sealed really tightly around the drum. In an earlier reply you mentioned that if the seals are bad/loose room air will be pulled into the dryer, which can cause the Cycling Thermometer to run hot. The day that the dryer stopped working was on a day that was butt cold (the dryer is in an unheated room that, thus far, never gets to freezing). Could this have caused the Thermal Cut-Off to go out?
[COLOR=“DarkRed”]Could this have caused the Thermal Cut-Off to go out?[/COLOR]
I cannot say for sure but it is possible.
Since the drum and ducting between the heater and the cycling thermostat would be cold then the heater may have stayed on too long.
The cycling thermostat would have seen a colder temperature than was actually true because the heat would be heating up the drum etc. so it would keep the heater on longer than it should have.
I like this scenario and think it could be the cause of the thermal cut-off going out. The dryer (e.g. cabinet, drum, ducts) would have been super cold to begin with and when I loaded it with cold, wet Levi’s it was just too much. In other words, there would have been a significant temperature gradient between the “box” on one side and the vent/exhaust on the other.
Since the cycling thermometer checked out okay, and there now appears to be a “possible” cause for the blown thermal cut-off, I am very tempted to not replace the cycling thermostat. What do you think?
Lastly, would I be creating a bigger problem if I were to temporarily bypass the thermal cut-off (by connecting its two wires together) and running the dryer? I would only do this briefly, without a load, and under very close supervision.
[COLOR=“DarkRed”]I am very tempted to not replace the cycling thermostat. What do you think?[/COLOR]
That is a decision that only you can make. If you do not re[place it then the odds of blowing another thermal cut off are higher but I cannot say how much higher. I guess it depends on how confident you are on the cold dryer theory.
Yes you can short out the thermal cutoff for testing purposes but only for a short test.
Shorting any safety device in a dryer can cause a fire so replace it ASAP after your test.
I replaced the parts that we discussed above and the dryer is again working properly (i.e. heating).
Thank you for your patience, expertise, and help. I especially appreciated your ability to lead me through the trouble shooting/repair process without making it too complicated. Not only did I get my dryer working (with your help), but I learned some things too. Thank you!
Hello. Reading thru this forum and I am having the same problem it appears. My Roper dryers heat will come on but just for a minute or two. Everything else appears to be working. i.e. timer, motor,etc. I have checked all the switches (high limit, cycling thermostat)with a ohm meter and all have continuity. Heating element checks ok and does not read that it is grounded out. Checked timer by testing black-blue connections. All is good. Vent is free of lint from unit all the way to outside. Driving me crazy.
Start a new thread using “POST NEW TOPIC”
Be sure to include the make and model number.
Adding to this post about a different model will just confuse things.
Also more detail on the problem.
Does it do this on full heat only or also on low heat?
Does the heat come back on later or does it shut off and stay off?
etc.
