Maytag dryer MDG7600AWW partially heating

[merrittjr]

The dryer is heating but it doesn't appear to be as hot as it's supposed to be. Exhaust has been cleaned out and nothing is blocked. Lint trap is clean. Any ideas?

[citizenX]

The venting is always the first suspect in these complaints but if the vent is truly clear and clean with no restrictions (or not crimped/smashed off anywhere if a flex vent) and the termination cap on the outside is clear and opening all the way then there are several other possibilities. 

If you are getting some heat initially then it goes cold, the gas valve solenoid coils, flame sensor, or cycling thermostat would be the first things I would suspect (in that order). Of course, there can always be other issues but those are the most common things.

Have you had the front panel off to observe the gas burner function? With a wet load, the flame should stay on for a while, maybe 15-20 minutes or more before it starts cycling off and back on. If the flame is only staying on for a few minutes or so but the glow ignitor is still cycling and the flame won't come back on, it is probably the gas valve coils. I have had a few flame sensors acting the same way but usually it's the valve coils. Those are simple and cheap to replace. If there is an airflow restriction though, the flame will still keep coming on but will back up in the burner tube and will trip the high limit thermostat which will stop the flame. If you can take off the front panel, then put the door back on and observe the flame operation with a wet load, that will help to determine what is going on. 

[merrittjr]

Double checked and there is no airflow restriction. Seems like the flame is on for about 7-8 minutes and then it shuts off for about a minute or so, sometimes more than that. Then the ignitor glows and I get a flame again. I don't know how often this cycle is supposed to occur. My family is telling me clothes aren't getting dry like they should. They're having to run it a couple cycles to completely dry. 

[merrittjr]

Also, are the valve coils known to go out fairly often? I just remembered that I've replaced those in the last 4-5 years.

[citizenX]

Well, the valve coils are probably the most common failure besides venting issues, but usually the way the coils will fail is that after they are on for several minutes, they will stop actuating the gas valve. What will usually happen is you will see the ignitor come on then click off without igniting any gas. If the flame is cycling on and off and it ignites every time the glow ignitor cycles, then doesn't sound like the coils unless they are dropping out after the dryer has been running for a while? Sometimes it can take a while for the coils to start dropping out. I've had them act up within a minute or two and sometimes also not until 20-30 minutes into a cycle. You can get a set of coils on amazon for ten bucks so its worth a shot. 

Normally, once the clothes start to get dry, the heat will cycle on and off many times just as you described until the timer gets to a cool down period and/or the cycle ends, so it sounds like yours is cycling normally. The number one problem with the symptom of needing to run the cycle a couple times is almost always the venting/airflow. If you are positive it is clear and not restricted but it is still taking too long to dry (multiple cycles) then I would suspect the cycling thermostat is not letting the dryer get to the proper temp. The flame sensor or limit thermostat could also be acting up intermittently but you would have a similar issue of ignitor glowing but no gas or no ignitor at all. This is where I'd take a temperature measurement and watch the flame cycling. 

I have had some of those old school maytags in the past with an intermittent push button temp switch on the console, but if that was bad you wouldn't get any heat at all. But now that I think about about it, a couple other things to check: make sure the duct housing where the filter goes in down to the blower wheel is not clogged up with lint.  Also, the blower wheel on these units like to get stripped out where the blower pushes on to the motor shaft. The blower should be very tight on the motor shaft and should not spin independently of the motor. If it is stripped and loose, it will still turn when the dryer is on but won't deliver enough airflow to work properly. 

 

[merrittjr]

Thanks. I'll report back when I can get to it. 

[Econo Appliance]

The coils can fail in a funny way, toward the end of the cycle the igniter will glow but the valve will not open the flame. Problem is you may have to wait 30 or 40 minutes before you can see the failure with your eyes, but being it's a family dryer, just let it run and let us know what you see

[merrittjr]

OK. And just so I'm clear, if the coils are going bad, there can be a flame at times and not at others? In the time I was sitting and watching it, whenever the igniter glowed the flame always lit. I never saw the flame not get lit. Granted, I didn't watch it from start to finish, but it was about 20-25 minutes total.

[citizenX]

17 minutes ago, merrittjr said:

OK. And just so I'm clear, if the coils are going bad, there can be a flame at times and not at others? In the time I was sitting and watching it, whenever the igniter glowed the flame always lit. I never saw the flame not get lit. Granted, I didn't watch it from start to finish, but it was about 20-25 minutes total.

Yes, that's typically how the coils will fail. You'll get a flame initially when things are cold but after it heats up then at some point (1-30+ minutes or more) you get just the ignitor glowing but no flame. Like I said before the coils are cheap and easy to replace so I'd just try that first and see how it does.