Dishwasher Problems
and Possible Solutions
(Borrowed
from 411homerepair.com)
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Dishwashers have a lot of components, so there are many sorts of potential problems. Here we address some of the more common problems and their possible solutions.
Warning! To avoid personal injury or even death, always disconnect your appliance from its power source before you do any troubleshooting or repair work on your appliance. Because some components may have sharp edges, use caution while working on your appliance.
It
doesn't work at all
It cleans poorly
There's no water entering the machine
The water doesn't drain from the machine
It's noisy
It leaks
The dry cycle has problems
The door has problems
The cycle doesn't complete
I see an error code
The detergent cup doesn't open
The cycle times are too long
If your dishwasher
doesn't work at all, check these:
Power
from the house
Door switch
Wiring
Timer or selector switch
Power
from the house
Is there power getting to the dishwasher? This can be difficult to test,
because dishwashers are usually wired directly to an electrical circuit,
rather than plugged into the wall. But at least check for a blown fuse
or a tripped circuit breaker.
Door
switch
The door switch is important because, if it's defective, the dishwasher
won't work at all. To reach it, you need to remove the control panel
cover, or sometimes the interior liner of the door. If it's defective,
you need to completely replace it.
Wiring
Often the main wiring connection from the house, at the dishwasher,
burns and breaks the connection. If that's the problem, the wires must
be repaired/replaced as necessary. If that's not the problem, check
the wiring to the door switch, the wiring between the door and the lower
part of the dishwasher, and the wiring to the timer. Repair any broken,
burned, brittle, or defective wiring, using the proper appliance-grade
wire and connectors.
Timer
or selector switch
Although it's uncommon, the timer or the selector switch may be defective.
If so, you need to replace the defective part, because neither of these
can be repaired.
If
your dishwasher is cleaning poorly, check these:
Water-inlet
valve
Internal filters
Drain valve
Spray arms
Water temperature
Detergent cup
Water-inlet
valve
Most cleaning problems are caused by the dishwasher not getting enough
wash water, so the water-inlet valve is often to blame. This valve is
usually at the bottom left or right of the dishwasher, behind the lower
access panel. It's the device with the main water line from the house,
a rubber tube to the dishwasher, and two wires attached to it. When
a water-inlet valve is defective, you may hear the sound that's usually
referred to as "water hammer." If the water-inlet valve is
defective, you need to completely replace it.
Internal
filters
Every dishwasher has some type of filter to keep large food particles
and foreign objects away from the pump assembly: Most modern dishwashers
have self-cleaning filters that don't need any routine cleaning. Some
have filters in the bottom of the dishwasher that you need to periodically
clean. You don't need any tools to remove the filter, and cleaning it
is easy. Consult your owner's manual to determine which type you have
and its maintenance requirements. If your filter is clogged, it may
be causing the cleaning problem.
Drain
valve
Some dishwashers have a valve (or gate) that should open only during
draining. If debris lodges in the valve, it can't close properly, so
water drains out during the wash cycle. Most dishwashers drain into
the garbage disposer. If yours does that, listen for water flowing into
the disposer during the wash cycle. If you can hear it then, the drain
valve may be clogged.
Spray arms
There's a spray arm at the bottom of your dishwasher--it may have a
tall spray tube mounted to the center of it. There may also be a spray
arm located directly beneath the upper rack of dishes and/or above the
upper rack. If debris is blocking the holes in the spray arms where
the water comes out, it could cause cleaning problems. Regularly inspect
each of the spray arms and clean out the holes as necessary.
Water
temperature
To get the best cleaning results, the water entering your dishwasher
needs to be hot enough. Try running the hot water in your kitchen sink
for about 30 seconds before starting the dishwasher, to pre-heat it.
Also, if your dishwasher lets you select a higher wash or rinse temperature,
try that to see if it helps.
To check the temperature of the hot water that comes from your kitchen faucet use a waterproof thermometer. If the water isn't 120 degrees Fahrenheit, your dishwasher may have trouble getting your dishes clean. You could increase the temperature of the hot water to the whole house--and therefore the dishwasher--by adjusting the hot water heater thermostat.
Warning!
To lessen the risk of scalding, don't set the hot water heater
temperature higher than 120 degrees Fahrenheit. |
Detergent
cup
Dishwashers don't perform their best if detergent is introduced only
at the beginning of a cycle, so add detergent to both parts of the cup.
If the detergent cup isn't opening, see the "The detergent cup
doesn't open" section, below.
There's
no water entering the machine
If there's no water entering your dishwasher, check these:
Water-inlet
valve
Float switch
Water-inlet
valve
The water-inlet valve lets water enter the machine. If this valve is
defective, you need to completely replace it. It's usually located behind
the lower access panel on the left or right side. It's the device with
the main water line (usually copper) from the house, a rubber tube to
the dishwasher, and two wires attached to it.
Float switch
The float switch is a small electrical switch that's located right below
the dishwasher "floor." Above the switch, on the inside of
the dishwasher, is a plastic cylinder that floats up as water fills
the dishwasher. If this switch is defective, or if the plastic float
gets caught or trapped in the raised position, the water can't enter
the dishwasher. If the float switch is defective, you need to replace
it.
If the water doesn't drain from your dishwasher, check these:
Drain
line/air gap
Pump
Drain valve and/or solenoid
Belt
Motor
Timer
Drain
line/air gap
A clog in the drain line or air gap (if there is one) is the usual reason
that a dishwasher won't drain. Often the problem is at the point where
the drain line attaches to the garbage disposer or household drain line.
If you remove this line, you can clear any debris from the hose or hose
connection. Be sure to reattach the hose before starting the dishwasher
again.
Pump
Your dishwasher pump ejects the water. The pump is usually mounted directly
to the motor, then attached to the bottom of the dishwasher. You can
reach the pump from inside the dishwasher, but first you need to remove
the lower rack, the spray arm, and the spray arm support. Look for an
impeller--a round plastic fan blade-type of device that spins around.
This is the wash impeller, which forces the water through the spray
arm. Beneath the wash impeller is the drain impeller, which is similar
in size and shape to the wash impeller. The drain impeller pushes the
water toward the drain port. These components make up the pump. If any
of the pump components are defective, you need to replace them.
Drain valve and/or solenoid
Many dishwashers use a drain valve with an electric solenoid. When electricity
flows to the solenoid, the valve opens and diverts the water to the
drain. Sometimes the solenoid, or the diverting lever, sticks and prevents
the dishwasher from draining or filling properly. Try to free up the
solenoid to lubricate the lever. Otherwise, you may have to replace
the solenoid or pump assembly. With these systems, the motor always
rotates in one direction. When it's energized, the drain valve diverts
the water. Other dishwashers simply reverse the direction of the motor
to drain the dishwasher. These units don't have a drain valve. Instead,
there's a drain hose connected directly to the pump housing.
Belt
One brand of dishwasher uses a belt to drive the pump. If this belt
is broken or has fallen off, replace it.
Motor
If the motor isn't turning or working, the unit won't drain. First check
to be sure you have power to the dishwasher. If not, see the section
"It doesn't work at all." If the motor hums but doesn't turn,
it may need to be replaced. Some dishwashers are susceptible to getting
stuck if you don't run them regularly. If you haven't run the dishwasher
for more than a week, you may need to manually spin the motor to free
it up. If the motor is defective, you need to replace it. Dishwasher
motors can't be serviced.
Timer
Part of what the timer does is control the motor and drain valve. If
the timer doesn't work properly, the water may not drain and you need
to replace the timer. This problem is not common.
If your dishwasher
seems noisy, check these:
Water-inlet
valve
Motor
Heater fan
Pump
Water-inlet
valve
An aging water-inlet valve can sometimes fail slowly, rather than all
at once. It can shudder on and off rapidly, causing the incoming water
lines to shake, rumble, and rattle--sometimes violently. If yours is
doing this, replace the inlet valve.
Motor
If it's the motor that's noisy, either of these may be the "culprit:"
As motor bearings wear out, they can become quite loud when the motor
runs. They wear out quickly if they frequently get wet, because the
water washes away the motor bearing grease. Bearings can get wet if
the spin seal is defective. Then there will also be water leaking onto
the floor beneath the dishwasher. Replace the seal if it leaks (read
about the main tub seal in the "It leaks" section, later).
If,
from beneath the dishwasher, you can see a round, plastic disc that's
mounted to the top of the motor (a "slinger"), it may have
broken free of the motor shaft. If so, it could be rattling around the
shaft while the motor is running. If that's the problem, you need to
replace the motor.
Heater fan
If the heater fan bearings are rusted or worn, they may squeal, or scrape
loudly during the drying cycle. If this is the problem, replace the
fan motor. Alternatively, the fan blade may be loose. If so, you need
to replace it.
Pump
Small fruit pits, toothpicks, and fragments of glass sometimes get stuck
in the pump. When this happens, open the pump and remove the debris.
The pump is usually mounted directly to the motor, then attached to
the bottom of the dishwasher.
To get to the pump, you usually need to remove the lower rack, the spray arms, and the spray arm support from the inside of your dishwasher. A dishwasher pump isn't obvious. Look for an impeller--a round, plastic fan blade-type device that spins around and pushes the water toward the drain. When you can see the drain impeller, you should be able to see the clogging debris.
If
your dishwasher leaks, check these:
Main
tub seal
Door gasket or seal
Water-inlet valve
Hoses
Note…
If the main motor of your dishwasher is mounted vertically, beneath
the center bottom of the dishwasher, the following instructions probably apply to you. But if your motor is mounted horizontally, the pump isn't serviceable--you need to replace the entire pump and motor assembly. |
The main tub seal is beneath the drain impeller. It prevents the water in the dishwasher from leaking out near the shaft of the motor. To get to the seal, which is inside the dishwasher, remove the:
1)Lower
rack
2)Spray arm
3)Spray arm support
4)Wash/drain impellers
Then pry the seal out of its housing and replace it.
Door
gasket or seal
Over time, door gaskets and seals harden and lose their ability to seal
properly. You can't repair the seals. You need to replace them if they've
begun to leak.
Water-inlet
valve
The water-inlet valve, itself, seldom leaks. But, the water-supply line
from the house and the rubber tube leading from the valve to the inside
of the dishwasher may leak. Tighten or repair/replace these as necessary.
The water-inlet valve could mechanically stick open. When that happens,
the water continues to flow into the dishwasher, which then floods your
kitchen. Turn off the water supply to the dishwasher, and replace the
valve.
Hoses
Behind the lower access panel on your dishwasher are several rubber
or plastic hoses. If the leak appears at a connection, try a new clamp.
If that doesn't work, replace the hose.
If the dry cycle has a problem, check these:
Heating
element
Drying fan
Thermostat
Heating
element
Your dishwasher has an electrical heating element that helps to dry
the dishes. If the element is burned out, the dishes won't dry properly,
and you need to replace the element.
Drying
fan
Many high-priced dishwashers have a small fan that blows air or heated
air into the dishwasher to speed up the drying process. If the fan is
defective, you need to replace it.
Thermostat
Some dishwashers have a thermostat that monitors the drying temperature.
If the thermostat is defective, the heating element may not cycle on
or off properly. If that's the problem, you need to replace the thermostat.
When your dishwasher
door has a problem, check these:
Latch
Springs
Hinges
Door seal
Latch
The latch on many dishwashers is adjustable. If your door is easy to
close but difficult to latch, adjust the latch to let the door close
more easily. If you can't see any way to adjust the latch, yours may
be fixed in a certain position. Check for other reasons for the latching
problem. If the latch has worn out in a way that makes it impossible
for you to close the door properly, you probably need to replace the
latch.
Springs
Your dishwasher has two springs that counterbalance the weight of the
door. If either or both of these are broken, the door feels quite heavy
and you need to replace both springs.
Hinges
The hinges are important to the door closing properly. If they're bent
or deformed, you probably need to replace them. Once bent, only rarely
can they be straightened well enough.
Door seal
If your dishwasher is new--or if you have just replaced a door seal--the
door may be difficult to latch for a week or two. If the tightness persists,
though, try adjusting the latch, if it's adjustable. If it's not adjustable,
there's probably nothing you can do immediately. But try running the
dishwasher on the highest heat cycle to help the seal conform to the
door. Otherwise, the seal should compress over time.
If the cycle
doesn't complete, check these:
Water-heating
cycle
Many dishwashers heat the wash and/or rinse water to a higher temperature,
as the cycle calls for it. In these cycles, the dishwasher pauses after
it has filled with water, waiting for the water to reach the pre-set
temperature. What happens next, depends, as follows:
On
some units, the pause is timed and the unit continues after the allotted
time.
On others, the cycle can't continue until the water reaches the higher
temperature. If you have this type of dishwasher and the water isn't
being heated (say, because of a problem with the heating element or
thermostat), after the unit stops at the heating cycle, it never continues.
When you repair the heating-system problem, the "cycle problem"
is fixed too.
Timer
Timers don't often fail. But if every other part of the dishwasher seems
to be working properly and the timer knob seems to be stuck in one place--doing
one function continuously--the timer may be at fault. Dishwasher timers
can't be repaired. If yours is defective, replace it.
If
your dishwasher has a digital readout and you see an error code
It
may indicate a problem with the unit. If this happens, look up the error
code in your owner's manual to find out what the problem is.
The
detergent cup doesn't open
When the detergent cup doesn't open, check these:
Timer
Bi-metal switch or wax motor
Detergent cup, itself
Timer
On many dishwashers, a plastic actuator arm mechanically links the timer
to the detergent cup. When the timer reaches the proper time in the
cycle, the timer activates a lever that opens the detergent cup. If
the linkage is broken or defective, the cup stays closed after you've
closed it. Check the link and repair or replace it, as necessary.
Bi-metal
switch or wax motor
A bi-metal switch is a simple electrical device that deforms when electricity
is applied to it. The degree of this deformation can be engineered to
concise standards.
The timer energizes the bi-metal switch inside your dishwasher door--directly behind the detergent cup--when the detergent cup should open. When energized, the bi-metal switch deforms away from the detergent cup latch, which opens the detergent cup. If the bi-metal switch is defective, it may not deform enough to open the cup. If that happens, you need to replace it.
On some dishwashers, the bimetal switch is wired through the heating element or motor circuit. If the element is broken (or open), or if the motor is drawing low current because of a low-fill situation, the bi-metal switch doesn't open properly.
Newer dishwasher models use a wax motor instead of a bi-metal switch. It's a sealed unit with wax that heats up and pushes a piston through to open the door. The wax motor, controlled by the timer, mechanically opens the door.
Detergent
cup, itself
The detergent cup itself can become clogged with old dried detergent
that prevents it from opening. Sometimes just cleaning the cup takes
care of the problem. If not, you probably need to replace the entire
cup assembly.
If your dishwasher's cycle times are too long, check these:
Water
pre-heating
Your dishwasher may pre-heat the water. If so, and if the water entering
the dishwasher is cool, the heater may take up to half an hour to heat
the water.
To avoid the wait, increase the incoming water temperature before turning on the dishwasher. Do that by running the kitchen sink faucet until the water runs hot. Or increase the temperature of the hot water to the entire house at the hot water heater.
Warning! To lessen the risk of scalding, don't set the hot water heater temperature higher than 120 degrees Fahrenheit.