Why Won't My Dryer Make Heat?

87
rate or flag this page

By Appliance Doc


Continuity Tester
Continuity Tester
Thermal Fuses
Thermal Fuses

 

Before attempting to repair any appliance please visit the the following link for safety advice.

Safety Tips

So, your clothes dryer won't produce heat. There are a number of possibilities for this problem. The first thing we must determine is the type of dryer we are servicing. There are only two types; Gas or electric.

If your dryer is electric, meaning it uses electricity instead of flame to produce heat, step one is to verify that the breaker to the dryer's electrical circuit is fully on. Since electric dryers require 240 volts to run, their circuit is run through a dual breaker switch. Sometimes only one half of the breaker switch will be off or fail which will supply enough power to make your dryer tumble but not enough for it to produce heat. Pop the breaker to your dryer off and on again and then see if the dryer will now produce heat. If it does, then have the breaker replaced. If it doesn't, you can verify that the dryer outlet is fully powered by testing it with a volt meter, You can learn how to use a volt meter here. If the outlet is fully powered then the problem definitely rests within the dryer.

Let's next deal with the failure common to both types.

You will need a continuity tester for this process. Directions for how to use a continuity tester can be found here.

After you have removed the power from your dryer and shut off the gas, you will also need to access the internal workings of your dryer. Directions for achieving access, specific to your brand, can be found here.

Most dryers have a thermal fuse located in the exhaust path. Depending on your dryer, the fuse will be found toward the front or the rear of your unit. Generally, if there is a removable back on your dryer then that is where you will find the fuse.

The two most commons thermal fuses you might find are shown in Figure 1. They are each roughly 1" in size. You will notice that the contact points are easily spotted for a continuity test.

In older units and some electrically heated units you will find a series of thermal fuses, looking like small tin cans, at various points along the heater assembly. These will also need to be tested before you can rule out thermal fuses as your problem. If any of the thermal fuses fails the continuity test, then it needs to be replaced. You can find reputable parts dealers at the top of this page.


Typical Dryer Heat Element
Typical Dryer Heat Element

Electric Dryers

After proving your thermal fuse(s) is/are good in your electric dryer it is time to move on to the next most likely possibility, the heating element. A typical heating element is shown in Figure 2. The element, as are all dryer electric heating elements, is comprised of metal coils supported on a framework with two contact points where wires are connected to the rest of the dryer. A break in this coil will stop the dryer from being able to create heat. Test the two contacts for continuity. If they fail, then you need a new heating element. You can find a diagram showing where each brand tends to place its heating elements here.

If both the thermal fuse and the element show continuity it is time to call a professional to service your electric dryer.

Gas Dryers

Gas dryers use a burner system to create heat. This system has a number of parts that are known to fail over time. Some you can test, some you must simply rely on symptomology to form your decision to replace or not to replace.

In Figure 3 you can see an entire burner assembly with the various parts labeled. Not all of these parts can be tested with a simple continuity tester. An ohm meter is now required to find your problem part. Directions on how to use an Ohm meter can be found here.

The parts prone to failure in your burner assembly are:

  • Igniter
  • Coils
  • Flame sensor

A burner operates in a fairly simple way. Once the motor is turning, centrifugal force closes the Motor Switch allowing the electricity to reach the Flame Sensor. The Flame Sensor allows the electricity to reach the Igniter, allowing it to heat up to a temperature high enough to ignite natural gas. Once the Igniter is hot enough the Flame Sensor breaks the Igniter circuit which allows the electricity to run through the Coils that open the gas valve. Gas then flows out past the Igniter and catches fire and the heat is drawn into the airflow within the dryer.

Troubleshooting Gas Dryers

Observation is key to troubleshooting a gas dryer. Does your dryer get hot at the beginning of the run but finish out cold? Does it never heat at all? Do you hear a chattering sound at times?

If your dryer is hot at the beginning of the run but finishes cold then it is likely you have bad coils. As coils age, they lose the ability to hold the gas valves open. Sometimes this will cause the valves to open and shut rapidly, resulting in a chattering sound. Unfortunately, you can't test the coils to verify the failure so replacing them is a decision based on the above observations.

If the dryer never heats, then there are more items to check and test. The first item is the Igniter. There is a molex (clear plastic) connector attaching the Igniter to the burner circuit, Disconnect this and place your probes onto the two contacts on the Igniter side of the connector. The meter should read under 100 Ohms of resistance. Any reading above this value means that the Igniter needs replacing. You will find directions for replacing an Igniter here.

If the Igniter passes your test then you need to test continuity on the flame sensor, You should have continuity between the two contacts. If not, then you need to replace the flame sensor. Directions for replacing the flame sensor can be found here.

If all of the above pass their tests, you need to make certain that there isn't a build up of dryer lint around the burner. Sometimes, lint will impede the gas flow preventing the unit from igniting.

If none of these things help, then it is time to call in a professional.

Print   —   Rate it:  up  down  flag this hub

Comments

RSS for comments on this Hub

kevindouglas09  says:
15 months ago

Hey,

I like your hub. Thanks.

Stu  says:
12 months ago

Thanks for a clear, logical progression of possibilities-very clear and useful-I was able to go through the steps and figure out that I needed a new heating element.

Beav  says:
11 months ago

The word "Here" for ignitor replacement is not linked. We have a gas dryer that's not heating. The ignitor never heats up (ie doesn't glow) when turning on the dryer and observing through the view-port. Would something else cause this other than a faulty ignitor?

Appliance Doc profile image

Appliance Doc  says:
11 months ago

Sorry for the delayed response. In most instances, the igniter is bad. On rare occasions the switch on the motor that verifies that it is spinning will go bad, which cuts out the heating circuit. Generally that would mean replacing the motor.

No matter what, though, you will need to get in there and start testing for continuity. Best bet is you will find that the igniter is bad or, possibly, the flame sensor.

Good luck.

Appliance Doc profile image

Appliance Doc  says:
11 months ago

Oh... you distracted me from the simplest possibility... the thermal fuse.

Joy skurka  says:
9 months ago

Thank you for you input on how to check whats not working on a gas dryer. It would have been more useful if your links to replace the igniter and flame sensor were active. You cannot click 'here' to open link. Just an fyi.

Appliance Doc profile image

Appliance Doc  says:
9 months ago

Well, the links aren't active because the pages do not yet exist. I started this project while recovering from an illness. It is now, and has for a long while, suffered due to my continued health. :-0)

John C.  says:
9 months ago

I hope you're over what was ailing you.By the sounds of it,you may have been quite ill. I'm happy for your return and hope for continued health in your concern.

mudd  says:
8 months ago

When the gas dryer is open, no clothes, and running. I see flame. I put it together, add clothes, and very little heat comes out the vent. I dismantled everything and de-linted everything, I'm a general contractor, so i think of myself as handy, but if I can't fix it soon, my wife will kill me. Sometimes a professional is the best answer. thanks 4 the help remember safty 1st.

Appliance Doc profile image

Appliance Doc  says:
8 months ago

You may have an intermittent failure. If so, the burner coils are the cause 95% of the time. If you wish to prove this to yourself, watch the flames cycle on and off several times. What you will eventually see if the igniter glow, then start to lose it's glow yet with no flames to be seen. The burner coils are what releases the gas for ignition and heating. They weaken over time and fail to open/hold open the gas valves.

Mike M  says:
8 months ago

Clear concise instructions on troubleshooting a gas dryer. Very much appreciated. Checking continuity on the igniter was the key. Thanks again.

Carmen  says:
4 months ago

thank you

Dan  says:
4 months ago

i just changed the ignitor and realized that i didnt have too. because the continuity checked fine. There are like four different places to check continuity. which is the flame sensor

Wesley Roswold  says:
4 months ago

My igniter resistance is 124 ohms. My meter is a professional instrument and is accurately calibrated. I replaced the igniter anyway and now the dryer works just fine.

Appliance Doc profile image

Appliance Doc  says:
4 months ago

To Dan:

The flame sensor sits outside the burner housing, even with the igniter (which rests inside the housing.

to Wesley:

It's possible your igniter simply wasn't getting hot enough, due to age, to effect the flame sensor. Not a common thing a dryer - happens all the time with ovens - but certainly possible. If the problem returns, I'd suggest replacing the burner coils as they can fail intermitently.

MP  says:
4 months ago

I think I have a bad ignitor it measures 63.6 ohms but one side looks jagged and chipped, the other side looks fine. How valid is a test of resistance?

Appliance Doc profile image

Appliance Doc  says:
4 months ago

There are times when an igniter simply fails to get hot enough to kick the flame sensor but they are rare in dryers. If it looks jagged (maybe with a white film somewhere along it) then it probably ought to be replaced. If this doesn't solve your issue, then look to the flame sensor or the coils. This is assuming you have already checked the thermal fuse, thermisters and such.

brad  says:
4 months ago

I have a kenmore 80s series with no heat. When I start the dryer it seems to fire up with a blue flame for a few seconds then there is a glow. The glow fades after a few seconds and every few minuestes I noticed the glow and then it fades. Does this sound like bad coils?

Appliance Doc profile image

Appliance Doc  says:
4 months ago

Yes.... classic symptoms of bad coils.

Colin  says:
2 months ago

Thank you sooooo much!

Appliance Doc profile image

Appliance Doc  says:
2 months ago

My pleasure :-)

art  says:
6 weeks ago

Whirlpool gas dryer heats for 10 seconds and then goes out.Changed coils,flame sensor and all thermosats.Can the motor switch be the problem

Appliance Doc profile image

Appliance Doc  says:
6 weeks ago

It would be very rare for the motor switch to fail intermitently. Were it bad, there would be no heat at all. When you say on for ten seconds, do you mean that is it for the entire time the dryer is running?

You should check to see if there is a circuit board behind the control panel. It would be a bit smaller than a post card and nearly as thin, located near the heat select switch. That's generally a Maytag issue but you might have one of those rare models from a year that Whirlpool was trying something new. IF there is a board like that, it could be your problem.

It's an odd problem... could be the timer, even. You'd have to take a voltage meter and trace out the voltages using the wiring diagram in order to be absolutely certain what is failing.

I'd say it is time for you to call in a technician since poking around a live circuit is ABSOLUTELY NOT RECOMMENDED FOR THE NON-PROFESSIONAL.

Good luck!

art  says:
6 weeks ago

Thanks for your reply.I changed the timer and temp switch another dryer I had and the same problem.

Appliance Doc profile image

Appliance Doc  says:
6 weeks ago

I think you went the wrong way around. Swap the suspect parts, one at a time, to the unit you know for a fact is working properly. If nothing changes, then swap the parts back and move on to the next part. Slow going, but a rare trouble shooting opportunity.

Let me ask this.... well.. offer this.... When you press the start button on a whirlpool gas dryer, you will instantly hear a loudish click from the burner area. After a few moments, you will hear another click followed by the soft foom of igniting gas.

If you don't hear the first sound then you need to look at the thermal fuse/cutoffs throughout the unit. Also, the centrifugal switch in the motor would cause this fist action to fail. Also, of course, being in fluff would keep this sound from ocurring.

The second click will fail to evolve if the igniter fails to heat enough or if the flame sensor has failed.

No foom will mean that the gas coils have failed to enact.

Maybe this will help you out.

jason  says:
6 weeks ago

my electric dryer sparked out the back and then blew the main fuse. i reset the fuse box the drum spins but the heat does not work

Appliance Doc profile image

Appliance Doc  says:
6 weeks ago

Scroll up and start following the steps I have laid out. Sparks are dramatic and all but the troubleshooting is the same.

sharran  says:
5 weeks ago

strange. drum turns and not heat. read above and checked breakers (all 6 of them - elec. dryer) and while dryer is running, I turn off all breakers and NONE of them turn the dryer 'offo'. Could it be direct wired sonhow or what? I know nothing abouthi except I had the box replace 1st- from fuse to circuit 2)larger box 3)elec. co. made me move wiring to new outside box (wiring was suppose to remain the same). House is 90 years old and no trouble for 14 years with two dryers until now.

Thanks,

S-

Appliance Doc profile image

Appliance Doc  says:
4 weeks ago

Have you checked the dryer's outlet and verified that there is 220V there?

Submit a Comment

Members and Guests

Sign in or sign up and post using a hubpages account.


optional


  • No HTML is allowed in comments, but URLs will be hyperlinked
  • Comments are not for promoting your hubs or other sites

working