How to fix a dryer that won't start? Clothes Dryer Repair Guide

A clothesline filled with wet laundry flapping in the breeze on a sunny day illustrates the three functions a clothes dryer performs: It provides heat, air and motion. Instead of the sun, the breeze and the clothesline, a dryer uses electric or gas heat, a fan, and a revolving drum. All three of them must work together or the laundry will not dry.

The mechanical parts of a dryer are more likely to fail than the electrical parts. So if your dryer stops working, check the mechanical parts first. Gas and electric dryers are similar; they differ only in their source of heat. In either type, suspect a broken belt if the motor is running but the drum does not revive. Turn the drum manually and listen for a thumping sound, a sure sign that the belt is broken and is hitting the drum as it turns. To replace a broken belt, remove the drum and slip a new belt around it and the pulleys that turn it.

Any dryer's electrical parts can be tested for continuity with a multitester, with the dryer unplugged. If the dryer will not start, check the most likely causes: no power at the outlet, a faulty door switch, a worn start button or a broken timer. If the dryer runs but does not heat, test the temperature control, the timer, the thermostats and, in an electric dryer, the heating element.

The heating element of an electric dryer must be replaced when it fails; the burner of a gas dryer can usually be repaired by a professional. But you can safely adjust a gas dryer's air-to-gas ratio for a hotter flame .

If clothes are drying slowly, check for a clogged lint filter. Then, for an electric dryer, test for voltage at the receptacle. It should be between 220 and 240 volts. Inadequate voltage to the heating element can cause it to produce insufficient heat. Next test the heating element for continuity.

A dryer that works only on some settings has either a malfunctioning timer or one or more faulty thermostats. The thermostats, located on the heater duct, the drum bulkhead or the blower fan housing, control the temperature of the heating element and the air in the drum. Two types of thermostat may be found, usually marked either L or F. The L-type thermostats break the circuit when the heat they are monitoring reaches about 200° F.; thermostats of the F type break the circuit after the temperature drops below a preset point. A safety thermostat breaks the circuit when the other thermostats fail. Most safety thermostats, once triggered, must be replaced; they usually are so marked. But some reset themselves once the dryer has cooled.

If all of the above parts check out but the dryer does not run, check the motor. A motor fails rarely and is the most expensive part to replace. Purchase of a new dryer may be preferable.

Before making any dryer repairs, turn off power at the main service panel or unplug the dryer. Dryer-cabinet panels disassemble differently, depending on the model. Some are screwed in place; some, like the model shown here, snap together with hidden metal tabs.

Anatomy of a clothes dryer

Turned by a belt, the steel drum that tumbles the laundry rides on wheel-shaped bearings mounted on the bulkhead. A motor-driven fan blows air heated by the dryer's electric heating element or gas burner (inset) through a perforated opening in the heater duct and the perforated back of the drum. The air then exits into the exhaust duct, laden with moisture absorbed from the laundry, On the way the air passes through the lint screen, which filters out lint and debris.

Several devices determine when and how the dryer runs. For safety, a door switch stops the motor when the door is opened. A timer controls drying cycles, and a thermostat mounted on the heater duct regulates the amount of heat produced by the heater. Operating thermostats, located on the drum bulkhead or the blower-fan housing, control the temperature levels inside the dryer drum. The safety thermostat is designed to shut off the heat if the dryer should overheat.

A Failed Door Switch and How to Fix It

Removing the top panel. Unscrew the top panel's retaining screws. (They are most commonly located under the lint screen cover, although on some models they are on the edge of the top panel, near the back.) Unfasten the front edge of the top panel, either by removing screws under the front edge of the panel or, on snap in models, as shown here, by inserting a 2-inch wide putty knife under the front corners of the top panel and pressing down on the concealed metal tabs until the panel springs loose. Raise the panel, and rest it on the hinges in the back or lean it against the wall so that it does not fall backward.

Testing the circuit. 

With the power turned off, remove the two wires from the terminals on the door switch and examine the condition of the terminals. If they are burned, replace the switch; if they are not, test the switch for continuity with the dryer door closed. If there is no continuity, open the door and depress the switch button manually several times, to make certain that it is not sticking. If the button does not work freely, replace the switch. If you can work it freely, close the door and test the switch again for continuity; if there still is no continuity, replace the switch.

Replacing a Faulty Electric Heating Element

Testing the heater. With all power turned off, unscrew and remove the back panel of the dryer cabinet, and disconnect the wires from the terminals of the electric heater. To test for a short circuit, set a multitester at RX1K ; place one probe of the tester on a terminal and touch the other probe to the surface of the heater duct. If you find continuity, the heater Is short-circuited and must be replaced.

Test the heater for continuity by touching the probes to every combination of terminal pairs; some dryer heaters may have three terminals and thus require three tests. For every pair of terminals the tester should show continuity. Lack of continuity in even one pair indicates that the heater is defective and must be replaced.

Removing the heater duct.Remove the retaining screws that hold the duct to the bottom of the cabinet. On some models the duct is also screwed to the top of the bulkhead; to reach these screws, remove the top of the cabinet (opposite). Slip the duct out of the cabinet, bottom first.

Inspecting the heating element. First remove the screws that fasten the heating element to the heater duct, and slip the element out of the duct. Then examine the heater coils; if you find any burn marks or breaks in the coils, replace the heating element.

To install a new heater element, slip it into the duct and reattach the screws.

A Plan of Attack for a Broken Drum Belt

Getting at the belt. Remove the top of the cabinet, then remove the front panels. The typical dryer shown here has two front panels a door frame panel, to which the door is permanently hinged, and a toe panel. Remove the toe panel first. Unhook the top of the panel by depressing the spring tabs at the center or ends of the panel with a putty knife. Pull the top of the panel toward you, and lift it off the brackets at the bottom.

To remove the door frame panel, unhook the door springs, located behind the toe panel (inset), and unfasten the screws that hold the top of the door-frame panel to the top of the side panels. Remove the door-frame panel.

Removing the drum

In some dryers, to remove the drum you must first unscrew it from drum support brackets or slides on each side of the cabinet (inset); in others, you must unscrew a metal strap on the inside back of the drum, which secures the drum to a bearing on the back of the cabinet. Then, with the drum detached from the cabinet, pull out the broken belt and lift the drum off its bearings; hoist it up and out, bracing it against one knee to distribute the weight. If the front and back openings of the drum look the same, mark the front before setting the drum aside.

Remove pieces of broken belt and any lint or debris. Check the drum bearings for broken or worn spots and replace the bearings if necessary. Spin the motor pulley with your hand to make sure it is rotating freely while the pulley shaft remains stationary. If the pulley binds or wobbles, or if the shaft rotates, replace the pulley. To remove the faulty pulley, unscrew its mounting bracket from the cabinet bottom and pry the pulley out of the bracket; then place a new pulley on the mounting bracket and reattach the bracket. Lift the drum back into position inside the cabinet.

Replacing the belt 

Loop the belt around the drum, centering it on the dark line left on the drum by the previous belt. In most dryers the belt is placed with the grooved side against the drum, but follow the instructions that come with the belt. Loop the belt around the idler, and then snake it around the motor pulley (inset).

Reattach any drum brackets, slides or tabs, the door springs and all of the panels.

Servicing the Dryer Controls

The start switch and temperature control. With all power turned off, unscrew the control panel and remove the backplate; the screws usually are along the panel's bottom edge. To check the start switch, disconnect the wires at the start switch terminals. If the terminals are not burned, depress the switch in the on position and check for continuity; there should be continuity. Then test the switch in the off position; there should be no continuity. If your results differ, replace the switch.

To check the temperature control, mark and remove the wires leading to it. If any terminal is burned, replace the temperature control; if not, lift the control panel and set the temperature control knob on any heat setting. Test for continuity; you should find continuity between at least one pair of terminals. Mark the pair. Repeat the test; at each temperature setting you should find continuity between a different pair. If you do not, replace the temperature control.

The timer and the timer motor 

With all power turned off, remove the control panel and back- plate (opposite), and disconnect the wires from the timer terminals, marking their location on a diagram. If the timer terminals are burned, replace the timer. If they are not, test the terminals for continuity. First turn the timer knob to a setting, then check all the terminals for continuity at this setting; you should find continuity between at least one pair. Mark this pair, then repeat the test at each of the other settings. There should be continuity between at least one pair of terminals at each setting except off-at this setting, no pair should show continuity.

To test the timer motor, unscrew it from the timer, set the timer on any setting, restore power to the dryer and observe the small timer-motor gear. If it does not rotate, replace the timer motor.

To replace the entire timer and its motor, pull off or unscrew the timer knob, then unscrew the timer from the control panel. Following the diagram you made when the wires were disconnected. attach the wires to the new timer. To replace only the timer motor, connect it as the original motor was connected.

Three Thermostats to Check

Testing for lack of heat or overheating. With the power turned off, remove the back panel of the cabinet and locate the thermostats. If the problem is inadequate heat, test the thermostats at room temperature. First disconnect the heater thermostat and test its terminals for continuity . The heater thermostat is always of the L type and should register continuity between one pair of terminals; if it does not, replace it. Test L-type operating and safety thermostats in the same way. Flowever, if the operating and safety thermostats are of the F type, the test should yield reverse results: When operative, F-type thermostats should show no continuity between any pair of terminals.

If the problem is overheating, test the operating thermostats in the presence of heat. Remove them one at a time and hold them with pliers 1/2 inch above a candle flame for no more than a minute, until you hear a click. Then test immediately for continuity If they are L-type thermostats, there should be no continuity between any pair of terminals; if they are F-type thermostats, the results should be the reverse. Test a safety thermostat in the same way unless it bears a warning label. Some L-type safety thermostats are designed for one-time use, and when overheated will click open and stay open.