29 replies to this topic

[PKRWUD]

Greetings,

 

This is about my Kenmore gas dryer, model number 1108751110. The problem is that the gas flame only lasts for about 8 minutes, then abruptly shuts off. It won't reignite again for about an hour. The igniter works fine, the problem appears to be that the gas is just shut off after about 8 minutes, and will not relight until after the dryer has been turned off for about an hour.

 

The research I was able to do suggested that the coils were bad, so I ordered new ones and replaced them, but the problem is unchanged; it starts on the first try and heats for about 8 minutes, and then the gas shuts off. The dryer continues to run and sounds like it's working fine, but when I open the lower front panel, I can see that the flame has gone out.

 

I'm really hoping this is something relatively easy to diagnose and repair. I do have tools and skills, just no knowledge when it comes to gas dryers.

 

Thank you for your time.

 

 

Take care,

          ~Chris

[RegUS_PatOff]

... the gas flame only lasts for about 8 minutes, then abruptly shuts off. It won't reignite again for about an hour.

... The igniter works fine,

 

1) try an empty load with the Vent disconnected

2) When the Flame should re-light, is the Ignitor glowing ?

[PKRWUD]

I have tried it with the vent disconnected, and it made no difference. 

 

After the flame goes out, I haven't noticed the igniter trying to relight it, but I haven't watched it that long after it goes out. What I do is open the door to stop everything, close it, and hit the start button. The igniter lights up for 8 to 10 seconds, and then goes out, with no flame. After the machine has been off for about an hour, it will relight, and the same cycle happens all over again.

[RegUS_PatOff]

... and this Dryer has worked OK up till now at this location ?

 

sounds like it may be a bad Flame Sensor (thermal switch)

http://www.repaircli...sp?R=154&N=2681

[PKRWUD]

I've had this dryer since it was new, probably more than 20 years. About ten years ago I replaced the rollers and belt, and everything was great. Over the past year, it seems like it's been taking a little longer to dry the clothes, so I cleaned out the vent. This current problem started a few months ago. I was drying a load, and after an hour the clothes were cold and wet. I restarted it and could feel it getting warm, but after an hour the clothes were still damp, and there were no signs of any heat. That's when I removed the lower front panel and watched what happened, and it's been that way ever since.

 

How do I test the flame sensor?

[PKRWUD]

I just watched the video, and have a question; would it be easier to monitor the power to the coils and see if it goes off when the flame goes out?

[RegUS_PatOff]

there's (3) sections of the Coils...

Main

Assist

Hold

It would be tricky to monitor all of them...

Is there a Gas smell when it doesn't re-light ?

View the Ignitor to see how long it's OFF when the Flame goes out...

[PKRWUD]

There has been no gas smell at all.

 

Tomorrow I will check the igniter as you suggested, and check the sensor for continuity, although I'm sure it will read good when I first test it. Perhaps the trick will be to test it as soon as possible after the flame cuts off. 

 

Regardless, I will post my findings tomorrow. Thank you so much for your time!

 

 

Take care,

          ~Chris

[PKRWUD]

Okay, here's my update:

 

I tested the flame sensor and the igniter for continuity and both were good. I started the dryer and it ran fine for 7 minutes, at which point the flame went out. I had a voltage sensor next to the two wires that come from the back and supply power to the coils, igniter and flame sensor, which lit up when I started the dryer and went out at the same time the flame went away. I let the dryer continue to run with no flame for 5 minutes, and the igniter never tried to relight it during that time. I then shut the dryer off and went to test the sensor and igniter for continuity again, but it took me about ten minutes, and by then both tested good.

 

I then restarted the dryer, and it worked just fine, but the flame only lasted for 4 minutes this time. I shut the dryer off and again tested the sensor for continuity. As I had my leads attached, it went from open to closed. I did it all one more time, and this time the flame only lasted for two minutes, and the sensor was open for a few minutes, and then closed again.

 

I was surprised at how quickly it would work again, because before it took an hour of off time before it would reignite. This time it seemed to work again after only a few minutes, but the length of time it would remain lit grew shorter and shorter with each try.

[kdog]

Okay, here's my update:

 

 I had a voltage sensor next to the two wires that come from the back and supply power to the coils, igniter and flame sensor, which lit up when I started the dryer and went out at the same time the flame went away. 

 

This would indicate a thermostat is opening (high limit ?) as the exhaust temp rises - if you run the dryer empty, that temp increases quite fast.  You say you ran it with vent disconnected, is there a good flow of air from the back ?  Any way you can measure the exhaust temp while it runs ?

[PKRWUD]

This would indicate a thermostat is opening (high limit ?) as the exhaust temp rises - if you run the dryer empty, that temp increases quite fast.  You say you ran it with vent disconnected, is there a good flow of air from the back ?  Any way you can measure the exhaust temp while it runs ?

 

There was good flow from the back, and yes, I can get an approximate temp of the exiting air. I'll be back in about 15 minutes...

[PKRWUD]

Okay, this time it ran (empty) for 6.5 minutes before the flame shut off, and the exhaust temps were as follows:

 

At startup: 59.4º F

After 2 minutes: 104.2º F

After 4 minutes: 119.5º F

After 5 minutes: 136.4º F

After 6 minutes: 148.6º F

When it shut off after 6.5 minutes: 147.6º F

 

This time, however, I did hear a noise when it shut off that sounded like a very light tap of a metal trash can with a wooden stick.

[kdog]

That is the thermostat cycling that you hear - the above description sounds like a proper function so far - continue running until burner reignites etc and watch temp output. Running unit without a load is sometimes not a fair test but see what happens.

[jb8103]

I hope I'm not just adding noise here, but I recently had an elderly Rheem furnace with a mysterious short-cycle problem. Long story short, we opened the draft shutters all the way, and it cleared up.

 

I dunno, might be relevant here.

[telefunkenu47]

I would replace the operating stat and then check it. if the power to the gas valve in being interrupted by the stat and then not coming back for the relight, it can only be the stat, which is by the way, over ten years old. Am I right?

[PKRWUD]

Good morning Gentlemen, Merry Christmas!

 

I'm at a bit of a loss for words today because now it appears to be working properly. This morning I started it up and it worked fine for 6.5 minutes, and then the flame went off. I left it running, and about 5 minutes later I saw the igniter start to glow, and the flame restarted. 

 

I am going to try and do a load of laundry this afternoon and will report on my findings. I hope I didn't waste everyone's time.

 

Thanks again

[RegUS_PatOff]

if you monitor the Vent output temperatures,

The Flame should normally cycle ON/OFF somewhere between about 135F and 160F

It would take longer between "cycles" when running with actual wet clothes.

[PKRWUD]

Thanks for the info! I just finished washing a load of clothes, and am about to try drying them. I have a FLUKE 65 infrared thermometer.

[PKRWUD]

Well, here's one more update. With a load of wet clothes, the dryer has been running for 20 minutes so far with the flame on, and the exhaust temp hasn't exceeded 117º F, and in fact seems to be averaging around 110º F. So far, so good. I will check on it in a few minutes, and give another update when it's finished. 

 

Thanks again for everyones help, I really do appreciate it!

 

 

Take care,

          ~Chris

[PKRWUD]

Also, one more footnote; today I tested the old coils that I replaced for continuity, and there was none with either coil. I don't know if that means anything, but I thought I would mention it.