LG Tromm Gas Dryer won't Heat

[domain]

Suspecting 6931EL3004B is the HI-LIMIT THERMOSTAT I need, despite what the LG service manual says.
http://www.repairclinic.com/PartDetail/High-Limit-Thermostat/6931EL3004B/1268367

First 3 digits of your serial number?

[domain]

Service bulletin from august 6th 2004, states that the thermostat has been changed from part#6931EL3004B ( http://www.repairclinic.com/PartDetail/High-Limit-Thermostat/6931EL3004B/1268367 ) to part#6931EL3003F which comes with reset able red button as seen here (  http://www.repairclinic.com/PartDetail/High-Limit-Thermostat/6931EL3003F/1365245 ) This states it applies to 2002 production models. It also states that it was changed to improve performance, productivity, and reliability. 

[the_bigham]

I think this is the whole serial - it is stamped on the top/rear and not behind the door as the manual implies.

The 6931EL3003F screw holes do not align on my unit - I would only be able to affix with one screw (which may or may not be OK).

[domain]

Looks like a 2002 model to me, (OLDER models also have the model/serial plate located on the upper left of the RIGHT side of the unit. This has been changed to behind door are since 2005 if I believe.) which means that previous post SHOULD apply! New burner tube may need to be ordered to be able to properly mount the updated thermostat to OE specs.(Not Drilling Hole in Tube)

[the_bigham]

Found the serial after pulling the unit out - first three digits are 305.

I also decided to get cute on my screw/hole issue... installed OK, but no luck. On test 3 of the diagnostic, it petered out at low 30 something degrees. It did the same thing with the old hi-limit installed too. Never makes it as far as the manual implies it should: "In normal state if displayed temp. is increasing. Temperature in 4min : 113°F (45°C)"

Cannot get it to heat now. Reached in there to push those buttons, which are impossible to tell if they actually click or even need clicking.

At this stage I now have a new M220 (6931EL3003F) and M230 (6931EL3003C) installed and a M220 (6931EL3004B) on the way.

Tempted to give up, even though I had success fixing the washer a couple years back! 

[domain]

I will await for WildImagination and John63 to offer their insight. Awesome techs right there.

[niobrara]

 

[domain]

?

[john63]

<<<Every site shows the wrong image for 6931EL3003F>>>

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Correct.

And if ordered/received---and has a *button*---it is also the *wrong* part.

This part is the HI LIMIT THERMOSTAT and is located at the 1 O'clock position on the gas burner assy.
It is also listed as M220 on the parts illustration.

Absolutely NO BUTTON should be on the HI LIMIT THERMOSTAT.

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<<<Not sure where to order the right part at this stage.>>>

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Try Marcone Appliance Parts

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<<<I have the 6931EL3003C I removed on my desk. I cannot get the button to click no matter the pressure I apply - do they break or does it have to be tripped by heat internally to click?>>>

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The THERMAL LIMITER will only "click" if it is *tripped*.
Using a test meter---the THERMAL LIMITER can be tested for "continuity".
If closed---good.
Of open (and will not "click" either---failed/bad).
I've never had one fail to reset.

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<<<Doubting this was broken at this stage....>>>

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Yes---based on your additional posts---it's clear that the gas burner is only functioning initially but not continually (intermittent).

This usually caused by the following (in most likely order):

1) Failing MAIN BOARD (6871EC1016C) The gas valve *relay* fails after one or two burner cycles.

2) Failing GAS VALVE ASSY (5221EL2002A) Valve 1 or Valve 2 fails after one or two burner cycles.

3) FLAME SENSOR (6501EL3001A) Erratic operation.

4) CENTRIFUGAL SWITCH on the MOTOR (4681EL1008A) Erratic operation.

The most common culprit on an LG gas dryer built 10 years ago---would be the relay on the Main Board.

To test---start dryer and run until burner flame no longer re-ignites (such as you've already discovered earlier).

Unplug the dryer.

Remove the front of the dryer but leave the door switch plug connected.

Set the front of the dryer off to the left (or have an assistant hold it)

Lower the top cover of the dryer.

Set the test meter to DC voltage test mode (direct current).

Pull off the plug to VALVE #1 (on the right side of the gas valve).

Place the test leads into the plug.

Plug in dryer.

Power on dryer.

Select the *Normal* cycle and press the START button.

There should be 90 volts DC at the plug.

If no voltage or less than 90 volts DC is present/shown on the meter---replace the MAIN BOARD.

NOTE: In the Service Manual---there's a *typo*.
           The Service Manual for the DLG0332W dryer shows/instructs the servicer to check for 120 volts AC
            at the gas valve assy plug(s).
            Disregard.

Try this step first (several times if needed) to test the reliability of the relay on the Main Board.

If the MAIN BOARD (relay) tests good/okay---we'll move on to the next most likely component---the GAS VALVE ASSY.
         

[john63]

<<<At this stage I now have a new M220 (6931EL3003F) and M230 (6931EL3003C) installed and a M220 (6931EL3004B) on the way.>>>

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The original HI LIMIT THERMOSTAT (M220 location) was: 6931EL3004B
It has been replaced by: 6931EL3003F

The 6931EL3004B should *not* be used.

It's not uncommon for parts jobbers/retailers to continue selling older/obsolete replacement parts.
Not deliberately though---they're simply unaware that a new/improved part has superceded the original.

[niobrara]

  ? , enjoy reading how John breaks issues down.Thank you.

[the_bigham]

Thar she blows - note how it drops after a a little bit of time. At the end I show where I plugged in the meter:



Seems like the same type of thing I swapped on the washer a couple years back or so...

Manual says 6871EC1061B, so I assume 6871EC1061C [not 1016C - assumed type  ]  is the improved version for DLG0332W?

[john63]

<<<Manual says 6871EC1061B, so I assume 6871EC1061C>>>

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Good catch

The part number that I posted earlier (6871EC1016C) is **incorrect**.

Correct part number is: 6871EC1061C

[lesguns]

what is your line voltage?

[john63]

Hmmm.

6871EC1061C has been discontinued.

May need to send your board to fixyourboard.com (rebuild)

ADDL NOTE...

The 6871EC1061B Main Board is for an LG *washer* model: WM2077CW
 
That *could* be a typo on LGs website though (not entirely uncommon).
 
Best thing is to call LG Parts Research---I'll post on Monday evening.
 
Lots of typos going around on this particular thread