How Clothes Dryers Work
On this page, I will explain how clothes dryers work to help you better
understand how to repair your dryer. Use this page along with my dryer repair
guide and you can repair your dryer yourself. Three things must take place for a
dryer to work properly: the tub must tumble, the fan must provide airflow and
the heating source must provide heat. A mechanical timer or an electronic
control controls all three of these actions. Below I will explain each of these
actions in more detail.
Tumble
The tub must tumble in order for
the clothes to dry. The tub tumbles slowly so that the clothes will fall through
the hot moving air half way through the rotation of the tub. A belt wraps around
the entire tub and attaches to the motor pulley. The tub is about two feet in
diameter and the motor pulley is about one inch in diameter. This means that the
gear ratio is low. This makes the tub turn slow but with a lot of power so that
a very fast but weak motor can turn the tub. Dryer belts, pulleys and motors can
be purchased at clothes dryers cannot dry clothes without proper airflow. The AppliancePartsPros.com. airflow removes the moisture from the clothes and moves it
through the vent. This is why dryers will not work if the vent is stopped up;
the moisture has nowhere to go. A fan that is directly attached to the motor
creates airflow. The fan sucks the air and moisture out of the tub and blows it
down the vent.
Clothes dryer airflow example
Heat Source
Electric
Dryers- The heating element uses 240 volts to heat the air around the
heating element and the fan sucks the heat through the tub removing the moisture
from the clothes. The heating element is a high resistance wire that creates
heat when current passes through. The location of the heating element varies
with different model dryers. On GE, Frigdaire and some Maytag dryers, the
heating element is located directly behind the tub. On most whirlpool dryers,
the heating element is located behind the dryer inside a vent that attaches to
the back of the tub. On most Maytag and some Whirlpool dryers the heating
element is located under the tub inside a vent that attaches to the back of the
tub. On GE dryers there are two heating elements so if one stops heating it can
cause a long dry time. Dryer heating elements can be purchased at AppliancePartsPros.com.
Gas Dryers- Gas dryers use gas as a
heat source and can hook up to a regular 120-volt outlet. Gas dryers will
operate on propane or natural gas but come set up for natural gas. So if you
have propane, you will have to buy a conversion kit to convert it to work on
propane. The gas enters a burner-housing normally located under the tub. But
before the gas enters the housing, an electric igniter heats up to the point
that it can easily light the gas once it enters the housing. Once the igniter
reaches this temperature, an electric gas valve releases the gas and the igniter
is simultaneously cut off. The gas is then lit into a flame that will remain
inside the burner-housing. Gas dryer parts can be purchased at AppliancePartsPros.com.
Controls
A mechanical timer, or an
electronic control, and thermostats control dryers. The controls will work
together to control the length of time that the dryer will run and how hot the
heat source will get. Dryer control parts can be purchased at AppliancePartsPros.com.
Safety Controls
Above I talked about how
clothes dryers work; now I will talk about how safety controls make dryers safe
to operate in your home. Safety controls are on all dryers to prevent fire and
injury to the user. Below I have listed all of the safety controls and explained
how each one helps keep dryers safe.
Door Switch- The
door switch stops the dryer completely when the door is opened. This is because
if a small child opens the door, of the dryer the rotation drum will not hurt
them. Dryer door switches can be purchased at AppliancePartsPros.com.
Hi-limit Thermostats- The hi-limit
thermostats cut the heat source off in the event it gets too hot. This is put in
place to prevent fire.
Thermal Fuse- The thermal fuse
cuts the dryer off in the event it becomes too hot to prevent fire. Thermal
fuses can be purchased at AppliancePartsPros.com.
Belt Tension Switch- The belt tension
switch will cut the dryer off if the belt breaks because if the belt breaks and
the heat source continue to heat the clothes can catch on fire. Note that not
all dryers have a belt tension switch; some rely on the other safety controls to
prevent this. Belt tension switches can be purchased at AppliancePartsPros.com.
Motor switches- Motors on clothes
dryers have two switches that close when the motor is running and open when the
motor stops. They are opened and closed by centrifugal force so that the motor
must be turning at full seed for the switches to be closed. One of the switches
allows the heat source to operate. This is so that the heat source will not
operate unless the motor is running. The other switch allows the motor to
continue to run after the user pushes the start switch. This is so that if the
dryer loses power while it is running, it will not come back on once the power
is reconnected until the user presses the start button again. The motor switches
cannot be replaced, if you suspect the motor switch is bad you must replace the
whole motor. However you can attempt to clean the motor switch by blowing it out
with compressed air and vacuuming it. Dryer motors can be purchased at AppliancePartsPros.com.
I hope this page helped you better understand how
clothes dryers work so that you can fix your dryer yourself and save.
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