Author Topic: Maytag gas dryer Model NGD7200TW  (Read 2060 times)

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Maytag gas dryer Model NGD7200TW
« on: July 04, 2013, 10:35:58 AM »
2007 floor model bought 2.5 years ago.  Burner burns for only 10 seconds, shuts off, off about 1.5 minutes then burns 10 seconds.  I have replaced coils( even though they tested good) = no change.  Removed high limit thermostat from circuit= burner continues to burn.  Sure looks like that is the problem, but reading another post whereas another had identical conditions, but replacing the coils cured his problem.  So I replaced coils, to no avail.  Is this high limit therm. the next likely problem?   It has a L230-50F in it.  Thanks for help.

Offline tgoods

  • Technician
    Moderator
  • Member Since: Jul 2010
  • Posts: 1509
  • Country: us
    • Buy me a beer through paypal
Re: Maytag gas dryer Model NGD7200TW
« Reply #1 on: July 04, 2013, 10:53:37 AM »
It sounds like you have a restricted vent.  Reconnect the limit thermostat to the circuit and try running it with the vent hose disconnected.

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Re: Maytag gas dryer Model NGD7200TW
« Reply #2 on: July 05, 2013, 08:00:06 AM »
I tested the high-limit thermostat yesterday with electric fry pan.  Thermostat opened at correct temperature.  Re-installed HLT, retested = same results.  re-tested thermistor which now reads 2.3K ohms rather than the 10K ohms measured previously and now motor runs, drum turns but igniter never comes on and of course, no gas flow.  So is it the thermistor?  With that new reading on the thermistor I will wait to test with exhaust pipe removed, unless you think that could still be the problem.  Thank you!

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Re: Maytag gas dryer Model NGD7200TW
« Reply #3 on: July 05, 2013, 04:06:26 PM »
Since last post I have tested with exhaust pipe removed= no change.  I then exposed the blower wheel and discovered that the vanes were @ half full of lint.  After cleaning and putting cover back on, retested.  What I have is after the thermistor has sat for awhile the resistance reads about 11k ohms and the igniter lights and the burner burns for @ 10 seconds, then goes out.  Immediately testing  thermistor shows 2.3K ohms at this point.  Is it the thermistor??

Offline jumptrout51

  • Technician
  • Member Since: Nov 2007
  • Posts: 1879
  • Country: us
    • Buy me a beer through paypal
Re: Maytag gas dryer Model NGD7200TW
« Reply #4 on: July 06, 2013, 06:57:33 AM »
Is the flame sensor adjusted correctly?
Take a Kid fishing.

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Re: Maytag gas dryer Model NGD7200TW
« Reply #5 on: July 06, 2013, 07:25:43 AM »
I am unaware of an adjustment for the flame sensor.  Can you tell me?  It does measure 0 ohms resistance.

Offline dab147315

  • Technician
  • Member Since: Oct 2010
  • Posts: 1491
  • Country: us
Re: Maytag gas dryer Model NGD7200TW
« Reply #6 on: July 07, 2013, 01:35:47 PM »
In your first post you said burner runs 10 seconds ,shuts off about 1.5 min. than burns for 10 seconds.My Question is do you see the glow coil glow and ignite and shut off and keep doing this fast rapid matter.Meaning comes on with heat goes off awhile and comes back on with heat but never stays on long?but is always igniting.If so you could have a weak flame sensor.Rare but have seen it happen.Part#338906.Thermistor at 77degrees will be around 10Kohms.I have had them check out good with ohm meter and be bad.May want to try a new thermistor.Or both parts good luck.Thermistor # 35001191.

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Re: Maytag gas dryer Model NGD7200TW
« Reply #7 on: July 08, 2013, 06:56:53 AM »
Glow coil comes on, in a few seconds gas ignites and burns for 10-13 seconds on first ignition.  Then flame goes out.  And glow coil is not on.  After @ 60 seconds glow coil comes on followed by gas ignites.  Gas burns @ 8 seconds this time and all following times.  Dryer continues this cycle of @ 8 seconds burn, flame out, 60 seconds no glow, glow on, gas burn.       In a properly functioning system, does the glow coil stay on or go off while the gas is burning?



Offline dab147315

  • Technician
  • Member Since: Oct 2010
  • Posts: 1491
  • Country: us
Re: Maytag gas dryer Model NGD7200TW
« Reply #8 on: July 08, 2013, 07:59:29 AM »
No glow coil does not stay on after ignites it is shut off by flame seńsor.It sounds to me that you have a bad flame sensor that keeps the glow coil off until thermistor cycle heat off.But you could have a bad thermistor.I guess this rapid cycle is with clothes in dryer to.One way to tell if flame sensor is bad would be to pull a wire off flame sensor after it ignites and with clothes in dryer.The flame should stay on until thermistor cycles which would be a long time with wet clothes in dryer.But you would have to make sure the wire you pull off does not touch anything metal or you.Might want to just change both parts as they don't cost that much.For your own safety .

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Re: Maytag gas dryer Model NGD7200TW
« Reply #9 on: July 10, 2013, 02:49:44 PM »
Today thermistor arrived.  Installed.  Same results.  Retested heat sensor in un-heated state = good continuity.  Upon flameout retests as open.  Watched with ohm meter and when the approximately 60 seconds of cool-down time passed, the ohmmeter jumps back to short.  I believe I have found the culprit and of course wish that I had done this test at the onset.  Hopefully next post will be that new flame sensor indeed makes the dryer operate correctly.

Offline Spannerwrench

  • Technician
  • Member Since: May 2012
  • Posts: 73
Re: Maytag gas dryer Model NGD7200TW
« Reply #10 on: July 10, 2013, 03:50:04 PM »
Sound like the flame sensor to me. It the contacts open and close rapidly due to being weak.

Offline dab147315

  • Technician
  • Member Since: Oct 2010
  • Posts: 1491
  • Country: us
Re: Maytag gas dryer Model NGD7200TW
« Reply #11 on: July 18, 2013, 10:26:51 AM »
So what did you find?


Sent from my iPhone using Tapatalk 2

Offline JWWebster

  • Technician
  • Member Since: Jan 2008
  • Posts: 8780
  • Country: us
  • SublimeMasterJW
    • Buy me a beer through paypal
    • JW's Sublime Appliance Advice
Re: Maytag gas dryer Model NGD7200TW
« Reply #12 on: July 18, 2013, 02:14:52 PM »
If it ain't the thermister, could it be the wiring back to the control or the control connection or maybe the control itself?
May the hinges of our friendship
        never grow rusty.

About the icons: The beer is tip link, if a tech saves ya some money buy em a 6 pack. The small green square=personal message. The green dot is a link to my web page on appliance repair and other general BS I love to post. The letter sends me email.
I love fan letters! LOL

Offline Bobaloo

  • VIP Member
  • Member Since: Jun 2013
  • Posts: 8
Re: Maytag gas dryer Model NGD7200TW
« Reply #13 on: July 19, 2013, 03:25:33 AM »
New flame sensor arrived.  Installed.  No change.  Studied wiring diagram and recalled that my original trouble-shooting indicated defective hi-limit thermostat(dryer worked fine with hi-limit therm. bypassed).  Further testing shows 117vac arriving at coil during burn cycle and absent when flame shuts off.  AC path goes back to operated heater relay through hi-limit thermostat. Observed AC present at output of operated relay during time burner not burning.  Which only leaves the hi-limit thermostat in the circuit.  Ordered, received, installed hi-limit thermostat.  Dryer works fine!!
In the beginning I had steered away from replacing hi-limit thermostat after reading another post with same conditions and test, with no change after replacing hi-limit therm.
Note:  supposedly OEM new hi-limit therm. is rated at 260 degrees with 60 degree spread.  The defective therm. is 230 degree with 50 degree spread.   Which raises the question---Was this original thermostat the wrong one???

Hopefully, my posting will help the next person doing a similar trouble-shooting.

Offline tgoods

  • Technician
    Moderator
  • Member Since: Jul 2010
  • Posts: 1509
  • Country: us
    • Buy me a beer through paypal
Re: Maytag gas dryer Model NGD7200TW
« Reply #14 on: July 19, 2013, 09:23:49 AM »
Good job. It's rare for a thermostat fail to like this.  They usually will just stay open and you will have no heat at all.  O0

 

maytag dryer model # md 3500 (no heat)

Started by #13

Replies: 5
Views: 6681
Last post December 05, 2007, 07:15:02 AM
by apptech
Maytag Model PYE4558AYW - Dryer not getting hot enough, AGAIN

Started by Shotgun

Replies: 36
Views: 4354
Last post March 27, 2012, 11:02:17 AM
by Shotgun
maytag dryer model #MDE308DAYW

Started by rodey

Replies: 9
Views: 1906
Last post May 07, 2012, 11:15:16 AM
by AJ
Maytag Performa Dryer Model Number PYE2000AYW Loud Thud & Burning Smell?

Started by bug34

Replies: 4
Views: 1551
Last post July 14, 2012, 10:46:14 AM
by JWWebster
Maytag Bravos dryer Model MEDB850YW

Started by jrjimenez77

Replies: 5
Views: 1138
Last post November 15, 2013, 10:40:58 AM
by LowSL2
LDG7304 Maytag Dryer - making a lot of noise.

Started by robert

Replies: 5
Views: 7697
Last post February 20, 2011, 07:33:06 PM
by jumptrout51