Why Won't My Dryer Make Heat?
So, your clothes dryer won't produce heat? There are a number of possible causes of this problem. The first thing we must determine is the type of dryer you have. There are only two types: gas or electric.
Warning: Before You Begin
Before attempting to repair any appliance:
- Turn off (unplug or kill the circuit to) electrical power, and
- Shut off gas supply (if applicable).
If you don't know how to do this, visit my article about safely shutting on and off gas and electricity.
Step 1: Checking Power
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 half of the breaker switch will be off, or will have failed, which may result in a supply of only 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 voltmeter. If the electric outlet is fully powered, then the problem definitely rests within the dryer.
If your dryer runs on gas, we will assume there are no kinks or stoppages in the line and the problem is in the dryer itself, although if you follow all the rest of the steps and still can't find the solution, you might investigate this as a source of the problem.
Step 2: Checking the Dryer's Internal Workings
Let's next deal with the failure common to both types (gas and electric dryers). You will need a continuity tester for this process. Here are directions for how to use a continuity tester.
After you have disconnected the power or shut off the gas, you will want to access the internal workings of your dryer. Directions for achieving access, specific to your brand, can be found in your owner's manual. If you don't have one, you might try Google or searching YouTube to see if anyone has uploaded instructions for your particular make or model.
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 the dryer, then that is where you will find the fuse.
The most commons thermal fuses you might find are shown in the illustration below. 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 in some electrically-heated units, at various points along the heater assembly you will find a series of thermal fuses that look like small tin cans. These will also need to be continuity 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.
Electric Dryers: Heating Element
After making sure your thermal fuse(s) is/are good, it is time to move on to the next most likely possibility: the heating element. This element 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 with a continuity tester. If they fail, then you need a new heating element.
If both the thermal fuse and the element show continuity, it is time to call a professional to service your electric dryer.
Gas Dryers: How They Heat
Gas dryers use a burner system to create heat. This system has a number of parts that tend to fail over time: Some you can test but some you must simply read the signs and make a good guess to replace or not to replace the part.
Not all of these parts can be tested with a simple continuity tester. An ohm meter is now required to find your problem part. Here are directions for how to use an ohm meter.
The parts prone to failure in your burner assembly are:
- 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, allowing the electricity to run through the coils that open the gas valve. Gas then flows out past the igniter and catches fire. 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 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 you make 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 ohm meter 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.
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.
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.