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Originally Posted by: Safetyguy  I replaced the high-limit thermostat yesterday with Genuine Whirlpool Part:
WPW10423382. Was fairly hard to reach with big forearms, but got it mounted and did a load of laundry. The dryer worked just as it used to for years. Clothes dried in 50-60 minutes on Normal/Permanent Press (Med/High).
Thank you for your assistance. Much appreciative! That's good. Sorry I spaced on coming back to this. For background info: It will tend to cycle on the high limit early in the run, since the op thermostat is in the exhaust and only seeing air that is cooled by the moisture in the load. As the load heats up the op thermostat will begin to see those temps and take over. If the hi-limit is opening early then it takes longer to reach operating temps in the exhaust and you get what you describe. That said thermostats in general on Whirlpools are not prone to failure often so this was a little odd, forced me think; which is good.
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I replaced the high-limit thermostat yesterday with Genuine Whirlpool Part:
WPW10423382. Was fairly hard to reach with big forearms, but got it mounted and did a load of laundry. The dryer worked just as it used to for years. Clothes dried in 50-60 minutes on Normal/Permanent Press (Med/High).
Thank you for your assistance. Much appreciative!
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Thanks! I think I'll just get a new high limit thermostat and try that for now.
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If you've jumped the hi limit and it still shut off at low temps all that's left is the operating thermo and you've changed it. I wouldn't expect the timer to be so consistent so I think that can be ruled out.
At this point I'd have to start looking for which component is opening. Each thermostat should have 120v to groundbon both sides if closed. If you don't mind working on live devices I would do it by checking for potential across the thermostat. When a thermostat is closed and allowing voltage to pass there should be 0 potential between the two terminals. when it opens that should go to line voltage of about 120 volts. So there's a potential difference between the two due to the open circuit inside the thermostat.
That's all well and good for me to say because I have become comfortable working on these things live but there is of course significant risk doing that when there is a spinning drum inches from your hand and lots of live terminals.
If you want to throw another 10 to $15 at it you could try changing the high-limit and see if that restores higher temperatures but you can also test for that as I just described and access to that one at least it is pretty easy. The operating thermostat located on the blower housing is less accessible.
That level of risk is up to you if you want to proceed with testing on alive dryer. I was very nervous for many months while I learned to work on live machines and 20 years later I still avoid doing it unless I absolutely have to.
I'm on a surprise all day road trip right now so I don't have easy access to look at a wiring diagram on a bigger screen but as far as I know the only thing that controls your temperature is the operating thermostat and the high limit thermostat. I should be back home tomorrow evening so I'll look again then.
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Also my wiring diagram shows it as part# 3403140 Thermostat High-Limit
205 degrees. Do you hink that is the culprit?
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I tried a digital thermometer with probe in the drum...it stops reading at about 157-159. I used duct tape on the safety switch and watch the fame at the same time. Good flame, hitting the spoon you mentioned, not near the high limit thermostat above it. Used the infrared again and it got to 161 and the flame shut off. It came on again in a few minutes but shuts off at 161 degrees. Does this mean that thermostat is bad? thanks again!
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That's low temps. On that dryer you should easily exceed 200 during burn. I use a wire probe in the drum and get temps peaking at 250 sometimes.
Watch it burn in the dark and see if it is allowing flame to hit or even get close to the high limit thermostat right above the burner. Or jump past the high limit and see if it helps.
I assume you've found the wiring diagram, worst case you end up tracking the power back to whatever is turning the burner off prematurely. There's only a few parts that would reset and allow it to begin ignition again.
I know it's a dead horse but just to be 100% on airflow pull the vent off the back and let it vent into free air. Open a few windows and see if temps at exhaust change.
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Originally Posted by: PNWDrew This is a very simple device. It only needs airflow and heat to dry, without having a temp probe in there you can't judge the heat. You can get a probe for many multimeters for $10. What temp is it shutting the burner down at? I just put the probe in the drum from experience but to be more accurate it should be in exhaust. I'll assume that you are correctly judging adequate airflow from here on so I'll focus on heat as your issue.
Your thermal fuse would either be open and not powering the burner or closed and powering it. It has no temp control function. You can ignore it if you get any ignitor or burner action.
There's not many options, only 2 thermostats operate this machine.
I've seen the "spoon" AKA flame spreader allow a jet of flame to escape and hit on or near the hi limit thermostat mounted on the burner cone, this shuts the burner off prematurely. You can see the burn marks on the inside of the cone near the thermostat if this is happening. You can carefully remove the spoon/air shutter assembly and bend the spoon up a little and often solve that issue. It's not elegant but it works. Since you have a lower panel you can run it with the lights off and see the flame spread, if a jet is hitting the hi-limit therm that is probably your issue.
The operating thermostat on the exhaust duct next to blower is the primary means of temp control. If it does not shut the burner off and airflow is good the thermal fuse will shut the burner down permanently at about 195F, or the hi-limit will open and kill the burner, however the hi-limit resets.
You need to determine what thermostat is actually opening to stop it from heating if temps are low. This means live testing with a multimeter. Are you ok with that? Thanks for the insight PNWDrew. I used an Infrared Thermometer to check the temps. With the drum spinning and the dryer on High I got a reading of 158 degrees at the heat inlet to the drum and 122 degrees at the exhaust vent with good airflow out. That being said I'm not too sure where to go from here. Don't really want to buy a new dryer just yet!
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This is a very simple device. It only needs airflow and heat to dry, without having a temp probe in there you can't judge the heat. You can get a probe for many multimeters for $10. What temp is it shutting the burner down at? I just put the probe in the drum from experience but to be more accurate it should be in exhaust. I'll assume that you are correctly judging adequate airflow from here on so I'll focus on heat as your issue.
Your thermal fuse would either be open and not powering the burner or closed and powering it. It has no temp control function. You can ignore it if you get any ignitor or burner action.
There's not many options, only 2 thermostats operate this machine.
I've seen the "spoon" AKA flame spreader allow a jet of flame to escape and hit on or near the hi limit thermostat mounted on the burner cone, this shuts the burner off prematurely. You can see the burn marks on the inside of the cone near the thermostat if this is happening. You can carefully remove the spoon/air shutter assembly and bend the spoon up a little and often solve that issue. It's not elegant but it works. Since you have a lower panel you can run it with the lights off and see the flame spread, if a jet is hitting the hi-limit therm that is probably your issue.
The operating thermostat on the exhaust duct next to blower is the primary means of temp control. If it does not shut the burner off and airflow is good the thermal fuse will shut the burner down permanently at about 195F, or the hi-limit will open and kill the burner, however the hi-limit resets.
You need to determine what thermostat is actually opening to stop it from heating if temps are low. This means live testing with a multimeter. Are you ok with that?
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Original owner of Kenmore 90 series; is taking way too long to dry even on high heat. I have replaced the fixed thermostat (3387134), the thermal fuse (3390710), and both valve coils (279834). Also replaced drum seals a few years ago. The flame comes on and stays on and looks OK. Vent is solid line and very short, only about 3 feet and totally clear of lint. Blower push air through vent fine. Just not hot enough and takes 2 times longer to dry with half loads only. What would the next step be? Thanks!
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