Whirlpool Dryer Takes too long to Dry

[Carolyn_C]

Model Number: LE5700XPNO
Brand: Whirlpool
Age: More than 10 years

I have a dryer made by whirlpool that was new in 1984. We bought it used a while ago. It takes 4 cycles to get a medium load dry. The element glows and the dryer heats. However, the element when we ran a cycle while checking the airflow, the element would glow for a few seconds and then kick off. I'm not sure if it's supposed to do that and I sound stupid right now or not. I searched online and the whirlpool site for solutions. I was directed to a site for parts. The site said it was the high-limit thermostat causing the issue. I would like to be sure that is the problem before I spend more money on this dryer. Any help would be appreciated. I've cleaned the dryer 3 times. This includes the house vent, the vent hose, and every inch of the inside of the dryer. Also took the Element out to check for breaks.

[denman]

See the attachment for a wiring diagram.
Although it is shown as a 6LE5700 it should be close or the same as your unit

First double check the vent holes at the back of the drum and the lint filter.
Sometimes they can get coated with fabric softener and must be cleaned with soap and water.

I doubt it is the hi-limit thermostat as this is just a safety device and should not open at all if the unit is working OK.
It is a good thing that you are replacing it as it's contacts are not as robust as the cycling/operating thermostat and they fail after repeated use.

If it is the high limit that is shutting the heater off, the most likely cause of your problem is a grounded element.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 10 to 12 ohms. The wiring diagram shows 13 to 16 ohm
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 a n
hot spot on the element which then heats up the hi-limit and it regulates the temperature.

It could be that the cycling/operating thermostat (on the blower housing) is not opening so the hi-limit has to control the heating element.
You can do a rough check of it by removing it from the unit and heating up it's metal face.
I use a soldering gun but you can place it on an electric stove element.
You should hear it click and then check it with a meter to be sure the contacts have opened.

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. Run the unit with it disconnected from the vent.
Check/clean the blower wheel. Sometimes they can strip out so they look OK but when they run they slip on the shaft.

The above is my usual blurb with some editing for your specific problem.
So you probably have already done some if not most of it.

If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.
4. When you start always short the meter leads together. This will tell you that the meter is working and if there is any 0 offset.

[Carolyn_C]

Thanx Denman for the info and for replying so quickly
. I will check the above mentioned components and let you all know what I find. I have a fancy ohm meter. You're right, it has proven and likely will continue to prove to be an invaluable tool. I've done some more work trying to figure this out/prove what the problem is. Located the Thermal Fuse on the blower housing. It was welded to the connection terminal on one side. My boyfriend has fixed the connection terminal. We tested the fuse and it reads good. I'm not sure how that's possible. We also found Charing on the wall near the outlet. Upon further inspection we found that the plastic cover for the outlet as well as the pigtail have evidence of overheating. (Some melted rubber on the cord and plastic outlet cover.) So we've replaced those with spares we had from previous dryers. Need to figure what caused it to overheat or arc. I'm thinking my gut was right the second time I tore this dryer down to thoroughly clean it 2 to 3 months ago. Bad ground which has or is shorting the main control board, or wiring harness issues.? What my uncle and I always did to fix the problem of a dryer taking too long to dry a normal load was check the most common culprit. The element, is not touching anything anywhere that it's not supposed to, has no breaks, and does heat. Also reads correctly when tested using the ohms meter. I let my boyfriend check this as I can't see the digits on the meter. He assures me the ohms are what they should be for an operational unit. Replaced the Thermal Fuse, repaired the connection terminal for the Fuse. Putting the high-limit thermostat in today, along with the cycling thermostat, and a few other things. I will be replacing one componet at a time, checking between installs to know what the actual culprit is/was. Hopefully one of these parts will fix it. However, if these parts don't fix the problem we have to decide whether or not its best to start buying any other patrs for this unit. So far we've had everything needed except the high-limit thermostat. For that we used a friend's repair shop to scavenge for it. Sadly, we were informed that he has passed away and his wife is selling all of the shops parts, tools, and racing memorabilia to whom ever is willing to buy them. At a huge discounted price on anything there. Otherwise, he could have come fixed this dryer for us. HARRY will be missed. I will update as soon as I am done with the dryer.