My Maytag dryer works well in the Timed Dry mode but in the Auto Dry mode it runs forever and does not dry well. In the Timed Dry mode it produces plenty of heat and works fine. What is happening in the Auto Dry mode that does not make the heat properly get to a level that allows the clothes to dry like in the Timed Dry mode? I suspect it is a thermostat or some moisture sensor problem. Help appreciated!

applguy

Autodry dryers don't actually "sense" the clothes. Only electronic dry dryers do that. The problem is most likely due to an airflow restriction somewhere. These usually occur in the vent duct that connects the back of the dryer to the outside of the house. These vents should be cleaned at least once every 2-4 years depending on what types of fabrics you usually dry, according to manufacturers. The best test for this is to pull the dryer out, disconnect the vent from the wall and start the dryer. Feel the amount of airflow coming out of the dryer, reconnect the vent and see how much air is coming out of the vent outside. It will be slightly less, but it should be close. If you cannot access the outside hood (on roof, etc.) you can also test this theory by disconnecting the vent from the dryer and try to dry a load in auto dry mode. If the load dries ok, then the problem is definitely in the vent. Any further questions are certainly welcome. Good luck.

jdpnagp

Please read the posting! The normal Time Dry works fine... therefore the venting cannot be the problem. Furthermore I have totally disconnected the vent and ensured airflow is smooth. There is no venting problem I guarantee. I don't know if mine is electronic or not and I don't know what you are alluding to regarding my dryer as one type or the other. It senses the moisture content when in the Auto Dry mode and turns off when the moisture is gone, ie the clothes are dry. Please reconsider.

applguy

I did read your post and I realize you said that time dry works ok, but that doesn't mean the vent is clear, trust me. After working on dryers for over 15 years, I think I know what I'm talking about. If I am going to be of any help to you, this needs to be dealt with in a systematic manner. Second, I'm glad you have removed the vent from the dryer, but you did not give that information in your first post. I'm not wanting to ellude to anything about your dryer, what I am telling you is that if your control panel says "auto dry", then it most certainly does not sense the moisture in the drum. Auto dry dryers utilize a system of cycling the timer motor with the element, and has nothing to do with how wet the clothes are. If there are 2 metal sensor bars inside the drum, then it is an electronic dry dryer, and then would sense the moisture in the clothes. I will also need a model and serial number so I can see exactly what dryer you have. Thanks.

2manytoys

applguy, I found and joined this forum while searching for the answer to the exact question in this thread. My problem is identical. I first thought of the "exhaust restriction" theory right off. So I pulled the dryer out, replaced the aluminum expandable duct work off and replaced it with new solid, 4" aluminum duct. I pulled the front off the dryer and disassembled the blower, including removing the squirrel cage and washing it thoroughly. I vacuumed every trace of dust out of everywhere. I reassembled and tested it only to find out that on "sensor dry", it shut off after 10 min. with the clothes still soaking wet. The heat is fine and all levels work. I run it on "timed dry" and it works fine. It has the two metal bars in the drum and it is a GAS dryer, not electric. It's a Maytag Neptune, 2002 model. Model number MD5500. It has worked on "sensor dry" perfectly until last week. The washer is removing the water properly so it's not that. I know this for sure, as the washer had had all its parts replaced 1 month ago. Gotta love Maytag!!!!!!!

applguy

The theory of operation is this: First, wet clothes are electrically conductive. As the wet clothes tumble, they touch the two metal bars in the drum. There is a capacitor on the control that is trying to build up a charge, but when wet clothes create a short from one bar to the other, this charge is released to the frame of the dryer, therefore discharging the capacitor. As long as the capacitor charge is low, the control knows the clothes are wet. As the clothes become dryer, they short the bars fewer and fewer times. Once the capacitor charge builds to a certain level, the control knows the clothes are mostly dry, and it advances the program to the final timed portion, usually less than 20 minutes, some of which is a cool down portion to reduce wrinkling. If your dryer is shutting off after only 10 minutes, that means the control capacitor is never getting discharged. This can be due to a few different reasons: 1. Blue or green wire behind the sensor bars is disconnected or broken; 2. Load is not large enough (remember the bars must be contacted repeatedly); 3. Bars are "coated" by fabric softener build up and need to be cleaned with Windex or 409. 4. Defective control board. 5. Airflow is restricted and moisture can't escape the drum. You have probably addressed the airflow possibilities well enough. Load size is probably not the issue, since you've had the dryer for a while. Clean the sensor bars and make sure the blue and green wires are connected well to the back of the block; orientation makes no difference. There is a diagnosic mode you can enter to test the control's ability to sense the bar contact that is illustrated in the tech sheet which is located within the control panel. Let me know what you find, or if you have further questions. Good luck. By the way, you do have a decent washer/dryer pair. Most of the problems these machines had were addressed before yours was built. What kind of repairs has your washer had?

2manytoys

Thanx for the reply applguy, much appreciated. The problem with the washer started with the "LR" code, lost rotor. There were 2 or 3 resistors blown on the motor control board. So, both the control board AND the motor were changed as the old motor wiring harness was not compatible with the new control board. Seems like a waste to me, as the motor was perfectly fine, but there must have been a change made that corrected the problem. The wax motor was fine. It really is a shame that Maytag has had these probs with these machines as they do work good when running. I have the tech. sheet and will try all you suggested, maybe today but more than likely Monday. I will let you know what I find. I've worked on a few machines before so I know my way around a fair bit. This digital stuff is just a little more intimidating but with sites like this, it should be no problem. The funny thing was, the repairman that came to look at the Neptune washer didn't know what the "LR" code was, I had to tell him. Go figure...........

2manytoys

applguy, I ran the diagnostic found on the schematic. Everything checked out OK including the system check and pressing the "sensor dry" button and not getting a "normal" LED. If the "normal" led lit up, it meant the sensor bars were shorted. I removed the sensor bars and cleaned them with a SOS pad and reinstalled with the same results. The two wires were connected but they were both blue not blue/green as you suggested. When I push sensor dry, the machine starts off at 63 min. then after 5 min. it goes to "cool down". It does this no matter what level of dry or heat setting you select. The temp. control appears to be working correctly as the exhaust pipe gets nice and warm on medium and hotter on Max. The dryer works fine on "timed" dry. What I'm wondering is, are you aware of a particular resistor that burns out on the control board? If so, I could replace the resistor and would be good to go versus replacing the whole frigging board. I could remove it and visually inspect it for "burns" but if you knew where the offending resistor is, it would help. Looking at the schematic, I see the wires from the "sensor" bars run to a "dryness sensor". Is this a possible problem area and is there really a "sensor" of some sort, further up the line? I am trying my best to avoid any contact with Maytag. I have given them enough of my hard earned coin. Appreciate your help, thanx.........

2manytoys

Bump....................

applguy

When you are in the diagnosic mode, you should remove one wire off the sensor bars and touch it to the other one to see if the light shows the bars are shorted. The point of the test is to see if the control "sees" a short on the bars or not. This test can be frivolous though because the diagnostic routines are a separate program on the control. The control can (and sometimes does) test ok in diagnostic mode but really isn't. I have had to replace the control board in the 5500 units only a couple of times, so it's not a common problem; it's fair to say it happens on all brands of electronic control dryers. Basically put, if it hits cool down after 5 minutes with a full load of wet clothes in it, but the diagnostic test shows the board can "sense" a short across the bars, then you have a bad control board. It's that simple (unfortunately). The 5500 is part of the third production phase on the Newton-built Neptunes. Most of the problems that the 3000 and 4000 series product had has been fixed in the 5500, 6500 and 7500 series units; The washer drive system failures are due to a vendor problem, so they now get them from a different vendor (which is why the new system is incompatible with the old system and must be replaced together), and I have yet to see one fail. The 3/4000 units had a machine control board (only in the washers, not the dryers) that had a whole mess of numbered resistors that could serve as a clue to find what component failed, but those boards are no longer in use. I have had people say they were going to try to repair their boards. They say they will call me and let me know if it worked or not, but they never do. I can only assume they were unsuccessful. I myself have never tried. I get the feeling from your question that you have been hearing or reading about these machines and I don't want to leave you with the impression that your machine control has problems that are similar to previous designs, because it doesn't. I would bet good money you won't find any blown resistors on this board. It's probably a problem with the software on the board and it just doesn't "read" the clothes correctly. All of the info I gave earlier about operation theory applies, but the two wires from the sensor bars simply connect to the control board. They haven't used a separate controller for years. Sorry, it's training time again, so I've spent a good part of the last week in training meetings and unable to check the posts.