Dead Clothes Dryer - Multi Meter needed

[eezlock]

dead dryer......

I have a dead Kenmore clothers dryer. I have found a couple of sites with appliance repair advice. Most of them recommend checking various parts with a multi meter and I don't have one. I need your advice on this new tool. First of all it seems worthwhile to by one versus the cost of calling a repairman. Although I have not done much electrical work or repair I figure I will always be able to find a use of the meter. But I need your advice. Is there a particular brand of or style of multi meter that I should get? Is this something I can pick up at Home Depot or should I special order this item? Are they all pretty much the same or can someone recommend the "better" models? I figured I would turn to some of the people I trust the most about buying new tools. So Loring, what should I do? And while we are on the topic, do you think taking a dryer apart and diagnosing the problem is something for an average woodworker/DIYer?

First off, get a multi meter at Radio shack or Borg or Lowes about $10.00
will work just fine. Then, take off the dryer receptacle cover, usually one screw in the middle of the cover, and then proceed to test the terminals.
The ones at a 45 deg. angle are the hot (power) terminals. The one at the
middle( straight up and down is the ground terminal. Between the two
hot terminals the voltage sholud be 220-240 volts, between either hot terminal and ground should be 110-120volts. If these check out normally,
your problem is in the dryer itself. Hope this helps....eezlock

[krogers]

Making progress

First of all let me say THANK YOU to everyone for the hlepful responses.

I picked up a 29-Range Digital Multimeter from Radio Shack with these specs. This should do the trick and work for future uses.

A precise and reliable multimeter. This 29-range digital multimeter is a compact, auto-ranging, digital multimeter ideal for testing in the field, lab, shop or home. It measures AC and DC voltage up to 600V, AC and DC current up to 10A, resistance up to 40M ohm, and tests 1.5V C, D, AA, AAA and 9V batteries. Continuity buzzer lets you quick-check cords, fuses, connectors and more. Diode-check tests semiconductors for opens and shorts.

LINUXRANDALL - I can turn a rachet. Have done so many times. I am very comfortable with power tools and will tackle any household project including plumbing. But electricity scares me. I have only changed 110v outlets and switches.

ATGCPAUL - Thanks for the tip. I might have that FH issue.

EEZLOCK - The main panel is 5 years old and the 220v/30a receptacle is under 10 months old. It is only 8 ft from the panel. Everything was working last week, so I don't suspect the power source. I must admit that I am reluctant to poke leads into 220v. But you say that it can be done.

Brian/Bigsteel15 - I was just looking for advice on the tool and fiigured the many appliance websites would help me with the repair. But I wasn't counting on the knowledge of the BT3 community and their desire to help in ANY situation. So I will bite at your offer.

It is a Kenmore Series 90 Electric dryer. 6 years old. Now when you push the start button nothing happens. There is a slight hum behind the timer dial if you listen carefully. But no motor movement. Several weeks ago the heat was shutting off intermittently during a cycle. At one point I couldn't get the heat on, just the drum turning. I took the front panel off, cleaned out lint and examined the connections/wires. Everything looked okay. I put all back together and everything worked fine. For four weeks. Given the BAD reputation this model and Sears has I have several suspects on the problem. The start button, the timer, and one of the two thermostats. I think I should start with the thermostat. You thoughts?

And one other thing to mention, other than using my tiny volt meter to see if an outlet is hot, I have never used a meter. I don't know how to check continuity or measure actual volt resistance. Everyone says to "do it", but doesn't explain how. (Loring probably measure this stuff in his sleep.) I assume the directions with the meter will explain the basics and how to set up the machine, but be prepared for some more (electronics) newbie questions.

[bigsteel15]

Being that it is only 6 YO, I'm not sure who actually would have made this unit. As far as I know, it could be either GE, Whirlpool or Frigidaire/White Westinghouse (WCI).
Either way, the solution should be the same, just different ways of taking things apart.
If you tell me where the heater element is located I can narrow it down.
If it is a vertical rectangular unit accessed from the back, it's Whirlpool.
Circular behind or in front of the drum, probably GE. I beleive WCI has a cylinder under the drum with the element in it.
First place I would check is the main terminal block where the cord comes in.
If you have intermittent heating, that usually indicates a thermostat. They are a PITA to diagnose. The high limit is usually the culprit. For the price, maybe replace it if you suspect it.
I wouldn't suspect the start button or timer unless the model has a bad problem with either of those.
As far as using your MM to check line voltage. READ THE INSTRUCTIONS. SAFETY FIRST.
To check continuity, one lead on each connection (with no wires attached) should beep to indicate a circuit.
Two leads on two power wires will show you differential voltage. You want 240 or close between the black&red (typically) at the main block.

[krogers]

I believe "cylinder under the drum with the element in it" would be the best description. Machine is a front loader with the lint screen in the door. The front lower panel comes off and reveals the blower fan to the left. Heating element is on the right side in a tube running front to back. It is a Kenmore Heavy Duty Series 90 Model number 110.60922990.

[bigsteel15]

Sounds like a WCI product or possibly new GE product.
I quit that career 10 yrs ago so haven't seen much new product (I have Maytag so haven't had to repair them) (OH! backhanded gloat?).
By the Model # I would have thought it is Whirlpool (110) and then I'm really out of touch.

Check those things I mentioned and let me know what you find.

[LinuxRandal]

As for use of a multimeter, I had more confusing training from my father. I found a better understanding of them through automotive repair manuals (like automotive diagnosis and repair) and through one of those $10 books that Radio Shack sells (they also help you understand those wiring diagrams). Use your taxes, check your library!

I based my first question on my father, as he is capable, but not comfortable wrenching or with electricity (other then electronics, DC, not AC) and tends to get hurt or zapped, everytime he goes near it.
Ohms is used to check for continuity (the multimeter completes the circuit). For everything else, unless you know what range it is in, best to leave it in the autoranging mode (it swaps faster then you could change it, some electronics would blow otherwise). In that mode, you should just have to select what you are checking (volts, amps)
As for 220, there is another type of tester that you can use for that, but since you have the meter, you should be fine. If you aren't comfortable, see about LONGER leads, and just make sure you hold them by the plastic.

[krogers]

More progress = more questions

Okay I did manage to get the meter up and running and despite what my mother taught me so many years ago, I stuck two metal objects into a 240v outlet. The outlet is working fine in that static state. I moved onto the dryer itself. I took the bottom front panel off and began testing some of the visible thermostats, fuses and the heating element. (By the way nothing is showing burnt or scorch marks that would indicate overheating in the wiring.) I may have located at least one problem, if not the problem. If I understand the process of testing correctly then one of the disposable thermal fuses is shot. But here come the electrical newbie questions that I warned you about. When checking continuity my MM reads either SHRT or OPEN. SHRT indicates "the circut resistance is less than about 50 ohms" and comes with an audible warning. Now when I think of a "short" in an appliance I think of the circut closing prematurely, and the opposite as being an "open" circut. But I think I have the termanology backwards at least compared to my multi-meter. So let me ask if I put the test leads on either side of a fuse and get SHRT reading then the fuse connection is broken. Correct? When testing a high limit thermostat (with dryer off and cool) I should get an OPEN reading because the circut is complete going from one pin to the other. Correct? Mentally that to me is a closed or completed circut, but maybe the label refers to the fact that the circut is complete or has an open pathway all the way around?

I found one of these [thermal fuse] that was "short" and is the current suspect.

[LCHIEN]

...
But here come the electrical newbie questions that I warned you about. When checking continuity my MM reads either SHRT or OPEN. SHRT indicates "the circut resistance is less than about 50 ohms" and comes with an audible warning. Now when I think of a "short" in an appliance I think of the circut closing prematurely, and the opposite as being an "open" circut. But I think I have the termanology backwards at least compared to my multi-meter. So let me ask if I put the test leads on either side of a fuse and get SHRT reading then the fuse connection is broken. Correct? When testing a high limit thermostat (with dryer off and cool) I should get an OPEN reading because the circut is complete going from one pin to the other. Correct? Mentally that to me is a closed or completed circut, but maybe the label refers to the fact that the circut is complete or has an open pathway all the way around?

I found one of these [thermal fuse] that was "short" and is the current suspect.

I think your problem is that you think short is bad and open is good. But that is not necessarily the case. Maybe the terminoligy is suspect used in the meter - maybe because that's the only word the could make with 7-segment chars (and not "CLSE").

Basically to an electrical engineer, the opposite of open is closed.
When something is open it doesn't conduct.
When something is closed it conducts. Your meter calls closed, SHRT.

A fuse should normally conduct, thus if good your meter will read SHRT.
A blown fuse, whether by thermal or overcurrent, will read OPEN.


A switch has both open and closed states, as do relays and thermostats.
thermostats can of cousre be open and closed depending upon temperature and they come in two styles one where its open at high temperatures and the other where its closed at hightemperatures, depending upon whether you want to control a heater (must be open when the temp is too high)
or whther you want to limit temperature.

The words short circuit generally have a bad connotation when used in real applications, the insinuation being that the short circuit is like a short cut, an unintended deviation of current like a piece of scrap metal across two terminals. An actual connection, if intended, will read SHRT on your meter although it's not a bad thing.

[bigsteel15]

I would say that "OPEN" means open circuit, no connection.
"SHRT" means closed circuit. This is a good circuit unless you're testing to ground in which case you have a SHORT.
The audible beep usually means there is a complete circuit. If you touch the 2 leads together you should here that beep.

That thermostat should be CLOSED except when it is heated to its rating.

EDIT:
OK, now I have to be looking at who is viewing the thread Loring?

[krogers]

So back to square one......

[QUOTE=bigsteel15]I would say that "OPEN" means open circuit, no connection.
"SHRT" means closed circuit. This is a good circuit unless you're testing to ground in which case you have a SHORT.
The audible beep usually means there is a complete circuit. If you touch the 2 leads together you should here that beep.

That thermostat should be CLOSED except when it is heated to its rating.


Okay, thanks for the primer. I think I had my understanding of the labels backwords. I understand the concept of open and closed circuts, but the labels on my MM and the common use of the word short got me off track. But I am rereading the meter manual and the direction for continuity. Does this paragraph seem correct to you?

"SHRT appears and the buzzer sounds if the circuit resistance is less than about 50 ohms (meaning the circuit has low ohmage or is shorted). OPEN appears and the meter's buzzer does not sound if the circuit resistance is greater than about 50 ohms (meaning the circuit is not shorted and greater htan about 50 ohms)."

Maybe I am confused on the definition resistance, but if the "resistance is less" doesn't that mean that the current is NOT going from one probe, through the circuit, and into the other probe? I think of low ohms not getting from one place to the other, that means the circut is "open" .

[LCHIEN]

50 ohms is small for most things (but 50 ohms is a power cord is really bad!) so the meter is sort of working to certain expectations.
Zero ohms = perfect short or closed circuit and infinate ohms (in all practicality for power circuits like in a dryer, 100,000 ohms or 100K ohms is open.)

I understand the paragraph you quoted perfectly.
You're kind of scaring me if you are not understanding the concept of open and closed and how that relates to volts, amps and resistance...

Before you continue with your dryer trouble shooting you better sit down with some simple circuit parts and make sure you understand how the parts work and how the meter works.
Otherwise you will be drawing oppposite conclusions to the truth.

[krogers]

More thoughts.

[QUOTE=LCHIEN]
Basically to an electrical engineer, the opposite of open is closed.
When something is open it doesn't conduct.
When something is closed it conducts. Your meter calls closed, SHRT.

A fuse should normally conduct, thus if good your meter will read SHRT.
A blown fuse, whether by thermal or overcurrent, will read OPEN.


Loring, I am sitting here reviewing your post over and over. I can't reconcile the my experience testing the dryer components with your instructions. And part of the problem may be that I actually tested the broken part and can't use that to figure out the labels on my meter. I tested the fuse and got a SHRT reading (with audible). But of course I don't know if the fuse is bad or good since I can't see inside it. But we have agreed that in this case the meter is indicating a CLOSED circuit and therefore the fuse is still good. Now compare that to the check I performed on the heating element. I touched one probe to each side of the heating element. Not the poles of the ceramic block, but the wire itself. This returned an OPEN reading. Since I can see that the element wire looks undamaged I would have thought that this would have been a CLOSED circuit. I check this first in order to understand my meter and that is what lead me down the wrong path I think? Unless of course I have miraculously stumbled on the problem on the first try and found a bad element. Does the length of the circut matter when testing? The current (is that the right word?) would have to go all the way through the spiral length of the heating element wire and back to the meter. Seems like a long way compared to just across the terminals of a fuse. Thanks for you help. I need to get un-confused about the terminology and labels on my meter before I can proceed.

[bigsteel15]

As I mentioned previously, the heater elements like to break inside the little ceramic insulators that hold them in place. Sounds like you have a dead element. I would take it out (the whole cylinder gets replaced) and double check it to be sure.
That said, this doesn't solve the problem of the dryer not starting, unless there is some kind of safety that won't start without a good element. That would be a new one on me.

[LCHIEN]

[quote=krogers]

Basically to an electrical engineer, the opposite of open is closed.
When something is open it doesn't conduct.
When something is closed it conducts. Your meter calls closed, SHRT.

A fuse should normally conduct, thus if good your meter will read SHRT.
A blown fuse, whether by thermal or overcurrent, will read OPEN.


Loring, I am sitting here reviewing your post over and over. I can't reconcile the my experience testing the dryer components with your instructions. And part of the problem may be that I actually tested the broken part and can't use that to figure out the labels on my meter. I tested the fuse and got a SHRT reading (with audible). But of course I don't know if the fuse is bad or good since I can't see inside it. But we have agreed that in this case the meter is indicating a CLOSED circuit and therefore the fuse is still good. Now compare that to the check I performed on the heating element. I touched one probe to each side of the heating element. Not the poles of the ceramic block, but the wire itself. This returned an OPEN reading. Since I can see that the element wire looks undamaged I would have thought that this would have been a CLOSED circuit. I check this first in order to understand my meter and that is what lead me down the wrong path I think? Unless of course I have miraculously stumbled on the problem on the first try and found a bad element. Does the length of the circut matter when testing? The current (is that the right word?) would have to go all the way through the spiral length of the heating element wire and back to the meter. Seems like a long way compared to just across the terminals of a fuse. Thanks for you help. I need to get un-confused about the terminology and labels on my meter before I can proceed.

length is immaterial to the measurement of resistance in that a long object is not necessarily has more resistance than a short object. It depends on the material. If the long and short are made of the same material then the
resistance MAY be greater for the longer one IF the width is the same...

As for the heating element, this is an actual circuit piece and depending upon the wattage it may or may not be more than 50 ohms. So you should not be using your meter in continuity mode - just misleading.
A 1000 watt element at 220V would be 48 ohms. and the value may be larger or smaller depending upon the voltage and wattage. You need to use the meter in resistance mode to measure actual ohms.

It may measure anywhere from 25 to 2000 ohms, I'm guessing. If it reads "OL" or flashes 1999 or something like that (depends on the meter) then the element is actually open.
If it does read that, then check your probes (touch one to the other) and it should read nearly zero (maybe 0.1 to 2 ohms) to make sure you have them connected right.

[bigsteel15]

[quote=LCHIEN]

As for the heating element, this is an actual circuit piece and depending upon the wattage it may or may not be more than 50 ohms. So you should not be using your meter in continuity mode - just misleading.
A 1000 watt element at 220V would be 48 ohms. and the value may be larger or smaller depending upon the voltage and wattage. You need to use the meter in resistance mode to measure actual ohms.

It may measure anywhere from 25 to 2000 ohms, I'm guessing. If it reads "OL" or flashes 1999 or something like that (depends on the meter) then the element is actually open.
If it does read that, then check your probes (touch one to the other) and it should read nearly zero (maybe 0.1 to 2 ohms) to make sure you have them connected right.

I never thought of that Loring. Most dryers will be 2000-3000 watts, so that would make it even lower ohms reading (16-25).