Maytag LDE9304ACE dryer wont heat

[gtmclean]

Hello,

I have an old Maytag dryer that wont heat. I am no expert and have been working through this with Youtube videos. Its very possible I am doing something wrong

This is what I have checked so far:

On back panel where power comes in:

Leg 1 Neutral to hot = 115V

Leg 2 Neutral to hot = 115V

Both thermal fuses have continuity

Both thermostats (Cycling and Hi-Limit) have continuity

Heating element resistance = 10.6 ohms

No short from heating element  input to case

No short from heating element output to case 

Temperature selector out voltage to chassis ground = 115V when running

Heating element voltage to chassis ground = 115V on both input and out sides when running (getting desperate here)

Could it be the switch in the motor that closes when it spins? I moved that switch by hand and got continuity across the terminals but I am not sure how to test while the dryer is running.

Any suggestions would be greatly appreciated!

Thanks

George

 

 

[16345Ed]

7 hours ago, gtmclean said:

Heating element voltage to chassis ground = 115V on both input and out sides when running (getting desperate here)

Is there 240V when running with meter leads on both heater terminals?

[WOOKIE]

2 hours ago, 16345Ed said:

Is there 240V when running with meter leads on both heater terminals?

 agree,  Your should read 240 across the power terminals L1 to L2.  Is this the only 240 v  appliance in your home? If not check for proper operation of the other appliances. If so, check the breaker . Are you getting 240 volt's at the output  of the ckt breaker  terminals for the dryer.  Could be a bad breaker .After you verify 240v to the dryer then you can look for internal failures the dryer. Possible open limit , burnt contacts in timer Etc..

[gtmclean]

3 hours ago, 16345Ed said:

Is there 240V when running with meter leads on both heater terminals?

Just to be sure I understand this: with dryer running, I should see 240V with meter leads on the heater terminals?

 

1 hour ago, WOOKIE said:

 agree,  Your should read 240 across the power terminals L1 to L2.  Is this the only 240 v  appliance in your home? If not check for proper operation of the other appliances. If so, check the breaker . Are you getting 240 volt's at the output  of the ckt breaker  terminals for the dryer.  Could be a bad breaker .After you verify 240v to the dryer then you can look for internal failures the dryer. Possible open limit , burnt contacts in timer Etc..

When I checked the terminals where the cord comes into the dryer from the wall I saw about 115V from neutral to hot on each Leg (L1 and L2). Should I also check for 240V across the two hots? 

Thanks the replies!

 

 

[ECtoFix]

57 minutes ago, gtmclean said:

Should I also check for 240V across the two hots?

Correct.  The 240v comes from the two lines.  Don't do any more testing of voltage to the element referencing neutral.  It's not part of THAT circuit. The element doesn't use neutral. 

 

[gtmclean]

I just checked and I do have 240V across the two lines at the back of the dryer. Any suggestions on what to check next?

 

[ECtoFix]

7 hours ago, gtmclean said:

I just checked and I do have 240V across the two lines at the back of the dryer. Any suggestions on what to check next?

So you've verified that you have 240v to the dryer.  Good.  Did you do the same test to across each side of the element?  Based on your prior tests results, you'll probably see 0v, but I still suggest you do that.

If you get 0v across the heater terminals,  then one of the legs (LINES) of 120v isn't getting to the element to provide the requisite 240v.  There are numerous control components and lotsa wires/connections that can prevent the 240v to be delivered to the element.  From one leg, the motor centrifugal switch could be the culprit.  From the other leg, a malfunction of the high-limit, cycling thermostat, timer or failed wiring/connection could be cause the problem.

Here's a schematic:

[gtmclean]

I have not tried the test across the heater. I will test that tonight. 

If I get 120V at the red wire on the temperature switch that connects to the cycling thermostat would that mean the switch and timer are OK?

Is there a way to test the motor centrifugal switch? I was thinking I could I could hold it open with something and turn on the timer but not the motor. Would that bypass the centrifugal switch? 

Thanks for the schematic, I have been staring at that for the last week and it is starting to make sense!

I  really appreciate the help.

[ECtoFix]

Just trying to give you some guidance.  FWIW - I don't work on residential stuff.  All commercial.  However, I DO have forty+ years of experience troubleshooting electrical problems.

So much for my disclaimer...

2 hours ago, gtmclean said:

Is there a way to test the motor centrifugal switch?

Here's a video I found on that:

 

[ECtoFix]

Referencing the video, the wire colors in YOUR dryer will be different colors.  Per the schematic, they should be black (#33) & blue (#20).

[gtmclean]

As you predicted the voltage across heating elements was 0V when the dryer was running.

Voltage across from each element to the chassis was about 120V. I am not sure what that means or if it is useful information. 

I was able to check the motor centrifugal switch by hand. With the switch closed I get continuity across Blue to Black which makes me think the side of the heater fed from L2 should be getting 120V.

If I am understanding the schematic correctly, L1 goes into the timer at BK 23 and out at BU 44 which then goes into the temperature switch. RD 42 is the output from the temperature switch into the cycling thermostat.

If I see 120V from RD42 to ground does that mean the timer and switch are OK? 

Is is possible that I get continuity across the cycling thermostat but it still is not working?

I am baffled a this point! Thanks

[ECtoFix]

1 hour ago, gtmclean said:

I am baffled a this point! Thanks

You're doing very  well with the schematic reading.  That is a poor example of one since it doesn't definitively reveal the ins-&-outs of the timer or the temp switch.  I got a little hung up on that myself.

Sure wish I could be there looking over your shoulder to help.  You seem pretty sharp.  I get your confusion, though.  I taught this stuff in the '80s at NAS Memphis to hundreds of students, so I know the hangups folks have.  I even know licensed electricians TODAY who still don't get it.

LOOK.  DON'T use neutral or chassis in your tests.  Neither are part of the element's power supply.  The TIMER motor?   YES.  The LIGHTS?  YES.  But...not the element.  The element's circuit is 240v. 

You may ask WHY you're still seeing 120v everywhere.  W-E-L-L, given the element is GOOD...and at least ONE of the 120v legs is getting to it - when you reference to neutral (or chassis) with the OTHER test lead, that simply means your reading verifies that at least ONE 120v leg is present.  IN YOUR case, what you're predominately seeing is the SAME 120v everywhere...EXCEPT on the other side of the OPEN (faulty) component.  THEN you're reading the other 120v.  But...you can't tell the difference at that point.

SO, you're obviously lacking the OTHER 120v (per the 0v vice 240v reading across the element).  How can you tell which and WHERE the difference is?  There are two ways to approach this.  Either way, the dryer must be running and set to call for heat.  Be VERY careful so you don't get shocked,  short something out or get wrapped up in moving parts:

• Disconnect one wire from the element, THEN make readings referencing neutral (just for THIS test).  In doing so, ONE WIRE will read 0v while the OTHER will be 120v.  Then you've narrowed it down as to which leg isn't getting to the element. 
• ANOTHER method is preferable. Again - with the dryer running - DO a "walk-around" with your test leads.  Read voltage across EVERY controls' two relevant terminals which supply the heater.  HOWEVER, you need to understand that you're looking for a DIFFERENCE in voltage.  That's basically how a voltmeter works anyway.  So, by "walking" your test leads around, you're looking for the control that's NOT closing.  All the GOOD components will read 0v (In THIS case, for the same reason as the element.  Lacking the other leg).  When you find that errant control, it will read the 240v.  THAT component is the bad one.

FWIW:  Here's a more linear view of the circuit I've drawn out to eliminate all the other crap on the schematic.  It's just the element and all the switching devices which must be closed to energize it:

https://ibb.co/pzbr7gw

 

 

 

[ECtoFix]

RE:  In the photo, centriful = centrifugal

[gtmclean]

Thank you for the clear detailed explanation regarding my 120V readings. It makes sense now. 

I am going to test in the morning with the walk-around method. I think even the one beer I've had and 240V would be a bad combination!

Your simplified schematic is great, thanks. I appreciate the education and your patience. 

[ECtoFix]

...and I wrote that with MORE than one beer down (CHEERS!).  I getcha though.  I'd wait too.

[Vance R]

I'll add my poor artwork to try helping. Red is L2, blue is L1. With motor running for tests. Put one lead on L2 of your terminal block and leave it there for these tests.

Put the other lead on the L1 (blue) side of the heater.

If you get 240 vac move that lead to the L2 (red) of heater.  If 0 vac - open heater, If 240 vac Move to the motor BLK 35 wire and recheck - 0 vac open wire, 240 vac move to the other side of motor blu 28 wire - 0 vac open centrifugal switch, 240 vac is probably a burnt terminal at motor or  open wire between motor and L2 of terminal block.  

If you get 0 vac flow the blue line back to L1 one item at a time until you get 240 vac. The item inbetween 0 vac and 240 vac is your problem.  At the temp switch the voltage probably come out on RD 42 wire, voltage goes in on BU 44 wire. At the timer the voltage comes out Terminal BD with BU 44. Not sure which wire is the input terminal BK with BU 44 wire or Y-BK with Y_BK 43 wire. Which ever wire is the heaveist is probably the one to supply the heater.

 

[ECtoFix]

Thanks, Vance.  Great points about the heaviest (thickest) wire being the one routed through the timer to the rest of the element's circuit.  The element would certainly require heavier wires to carry its current. 

That old "scanned" and nearly unreadable schematic (vice more modern PDFs) doesn't paint a clear picture at all.  Being there and seeing that setup would certainly tell a truer story.

I wasn't sure about which wire from L1 to timer was the right one EITHER. So I happened to have found & referred to that dryer's gas-heated sibling to clarify which timer terminal from L1 would be relevant.  Per this comparison, I'm 99% certain that L1's path to the element comes into the timer through BK23 (I think that's the number??? Sorta illegible):

 

[gtmclean]

Thanks to both of you for clarification on the heating circuit.

I also see BK 23 from L1 to timer in my paper copy of schematic.

Yet another question: Can I run the system without the dryer drum installed?  It would be easier to get to test points without the drum installed but I don't now if running without the drum installed would cause problems.

[Vance R]

1 hour ago, gtmclean said:

Can I run the system without the dryer drum installed?

Yup, the airflow won't be correct and the thermostats won't cycle correctly. No big deal in this case as the heater is not working. Something to remember  if you run dryer apart after the repair. The drum and front will need to reassembled to test correctly for proper operation

@ECtoFix Nice artwork!!

[gtmclean]

I was walking through the components and while testing the voltage across the motor switch (which was 0V) I heard a small crackling sound which I would guess was coming from the control panel up top. That made me nervous so I turned it off but I noticed the heating element had come on. I looked at the components in the top panel  but did not see anything that looked burnt or unusual. I have since turned it on a few more times and the heater works every time.

I am not sure if I should go forward and use it. 

[Vance R]

Loose connection or burnt terminal made contact.  Welcome to the intermittent world - it could work for months or just once. Carefully wiggle the wire on the temp switch and/or the timer with dryer running. It could be a burnt contact inside the timer. May want to pull the motor plug and check there as well.  If you can't find anything definite run it till it stops working. Then it should be more obvious and you'll know where to look first.

[gtmclean]

Back to no heat now so back to testing.....

Any recommendations on multi-meter leads? I am finding I need a few more hands and thought longer leads and alligator clips could be helpful. 

 

[gtmclean]

burnt terminal

I couldn't figure how to insert an image so hopefully the link above will work

The terminal in the motor switch going to BK33 looks burnt to my untrained eye. Could this be an issue? If so is the part with the two spades a common part? Maybe I can clean the terminal? Any suggestions on how to do that?

[Vance R]

I use a jumper lead ( alligator clips both ends) on the lead that stay put on L2.  Some times there is a hole in the bulkhead you can feed through to terminal block. Then just move the other lead from place to place.

[Vance R]

1 minute ago, gtmclean said:

Could this be an issue? If so is the part with the two spades a common part? Maybe I can clean the terminal? Any suggestions on how to do that?

Possible, contact arc when make or break connection.  It is part of the centrifugal switch sometimes those are available separate, sometime they are part of the motor. Fine file or emery board to clean contacts.