How Do You Test A Bimetal Defrost Thermostat? Locate the bimetal thermostat. ... Turn on the furnace or device and adjust the temperature control to turn it on. ... Plug in the hair dryer and aim the flow of heat at the bimetal thermostat. ... Replace the bimetal thermostat if it does not respond correctly to heat.
How do you check a bimetal defrost thermostat?
The defrost thermostat should be in the closed position when cold. Check to be sure the thermostat is opening at the correct temperature by placing it in water and slowly heating the water. Defrost thermostats are designed to open between 40 degrees and 90 degrees Fahrenheit.
How do you diagnose a bad defrost thermostat?
0:112:11Defrost Thermostat Testing, Troubleshooting - YouTubeYouTubeStart of suggested clipEnd of suggested clipIf your appliance's thermostat has a closing temperature of 30 degrees fahrenheit or above you canMoreIf your appliance's thermostat has a closing temperature of 30 degrees fahrenheit or above you can easily test the part for continuity by using a multimeter.
How do you test a refrigerator defrost sensor?
0:062:05Fridge Warm? Defrost Thermostat Testing, Troubleshooting - YouTubeYouTubeStart of suggested clipEnd of suggested clipSince you can't tell if a defrost thermostat has failed simply by looking at it you'll need toMoreSince you can't tell if a defrost thermostat has failed simply by looking at it you'll need to perform a continuity test a continuity test will determine if a continuous electrical path is present in
How do you test a defrost heater with a multimeter?
1:122:04Fridge Not Defrosting? Defrost Heater Testing, Repair - YouTubeYouTubeStart of suggested clipEnd of suggested clipNow use a probe to touch one of the components terminals and the second probe to touch the otherMoreNow use a probe to touch one of the components terminals and the second probe to touch the other terminal. If the meter reading shows a result between 0 and 50 ohms of resistance.
What happens when defrost thermostat fails?
If the thermostat is defective it may not be able to sense the temperature of coils and then won't turn on the defrost heater. If the defrost heater doesn't turn on, the refrigerator will never start the defrost cycle and will eventually stop cooling.
Should defrost thermostat have continuity?
Defrost heater is good if it has continuity between the leads and no continuity to ground. The defrost termination switch (thermostat) is good if it has continuity when cooled below 40 degrees.
How do you test a fridge thermostat with a multimeter?
0:120:50How to check a faulty thermostat using a multimeter - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd I've turned the dial to the lowest ohm rating a working thermostat should have a reading of zeroMoreAnd I've turned the dial to the lowest ohm rating a working thermostat should have a reading of zero or as close to zero as. Possible. This thermostat is reading zero one meaning it's fine.
Is a defrost sensor normally open or closed?
The defrost sensor, which is usually mounted on a tube of the condenser, must be closed. The sensor closes when the coil temperature is cold enough to frost or freeze. Once closed, the control board begins saving accumulated run time of the compressor.
How do you test a refrigerator thermistor with a multimeter?
0:051:35How to properly test a refrigerator thermistor - YouTubeYouTubeStart of suggested clipEnd of suggested clipOne of the most accurate ways to test your refrigerator's thermistors is with a glass of ice water.MoreOne of the most accurate ways to test your refrigerator's thermistors is with a glass of ice water. And i will. Explain. Why here i have this thermistor hooked up to my multimeter.
What is the resistance of a defrost heater?
Usually refrigerator defrost heater elements have a resistance value of <50 Ohms. According to this link it should have a resistance value of between 21-27 Ohms not 22,000 Ohms.
How do I test my defrost heater for continuity?
0:351:38How to Test a Defrost Heater on a Freezer | HD Supply - YouTubeYouTubeStart of suggested clipEnd of suggested clipOn this model the first thing you need to do is disconnect the wiring harness. Then remove it fromMoreOn this model the first thing you need to do is disconnect the wiring harness. Then remove it from the three clips at the bottom. If you choose to leave it in for testing. Simply set your meter to
What temp does defrost thermostat close?
Defrost Thermostat Specifications. This limiter thermostat cuts out when the temperature inside your refrigerator reaches 55 degrees Fahrenheit and kicks back in when the internal temperature drops to 20 degrees Fahrenheit.
How do you know if your defrost control board is bad?
Ice on the Refrigerant Coils The first sign of a failed to defrost control board is ice covering the refrigerant coils. The work of the defrost system is to remove the ice on coils by using the defrost heater to heat the coils to melt them.
How do I know if my freezer thermostat is broken?
If food freezes inside the fridge or its compartments, the cause may be a faulty thermostat. You can use an appliance thermometer to check the thermostat, or try increasing the temperature a couple of degrees. Then wait a day to check whether the food has become unfrozen.
How do I know if my thermostat is bad in my refrigerator?
To check the present condition of the thermostat of your refrigerator, you can raise a degree and wait for the machine to turn on automatically. If the thermostat fails to start, it might be there are some technical breakdowns inside your refrigerator.
What is the difference between defrost timer and defrost thermostat?
Defrost Cycle Once the defrost termination thermostat (a.k.a. defrost limit switch) senses a set temperature, it opens the circuit to the defrost heaters, shutting them off. The timer remains in the defrost cycle until the timer advances back to the cooling mode.
How to check if a bi metal switch is good?
Attach one lead to each of the wire ends, to test the bi-metal switch. If the meter reads zero on a digital Voltage meter, or if the needle moves to the right on standard Voltage meter, then your bi-metal switch is good. (If the bi-metal is still cold) If the meter reads one on a digital voltage meter, or the needle does not move on a standard voltage meter, then the bi-metal switch is bad and it will need to be replaced.
Can you reinstall an icemaker after testing a defrost switch?
Once you have completed testing the defrost bi-metal switch, put the evaporator panel back on and you also need to reinstall the icemaker (If applicable) You have completed the job!
Do you need to defrost a bimetal switch?
Note: Do not totally defrost the evaporator coils. You need the defrost bi-metal switch to stay cold. It needs to be cold in order for you to test it. The defrost bi-metal switch contact is closed when it is cold, and open when it is warm. You will find the defrost bi-metal switch fastened to the top right, or left corner of the evaporator coil.
Do you need to defrost a thermostat after removing the evaporator panel?
After the evaporator panel is removed, you will need to defrost the evaporator as well so that you can locate the defrost thermostat.
What happens if your bimetal thermostat doesn't work?
This can mean increased electricity bills, and it will decrease the life of your refrigerator. If the bimetal thermostat doesn't work at all, your refrigeration unit will soon fail, requiring you to buy a new one.
Why does my refrigerator defrost when it's not working?
If your refrigerator or freezer bimetal thermostat is failing, the thermostat may not be able to correctly sense the temperature of the coils. This can lead to the defrost heater turning on sporadically or not at all.
How does a defrost thermostat work?
Working in conjunction with a timer the defrost thermostat controls the heater which turns on briefly when the bi-metal strip closes the circuit. The duration of the heat cycle is controlled by the timer. This action is not triggered by the frost itself, but rather by the freezer temperature. Even if there is actually no frost present the defrost cycle takes place.
Why is my refrigerator leaking?
The refrigerator or freezer is leaking. If you see water on the floor, this could be a sign of a bimetal thermostat failure.
Why is my freezer frost free?
Did you ever wonder why your frost free freezer is indeed frost free? It's because inside every one of these appliances is a heater. This heater melts any frost before it can accumulate and evaporates the moisture away. The little device that makes this possible is the bi-metal, or defrost, thermostat. It is called a bi-metal thermostat ...
What happened before frost free freezers?
In the old days, before frost free freezers, this ice would build up to the point where a freezer door could not be shut. When this happened it was necessary to remove everything from the freezer and melt the ice away. Advertisement.
What is a bi metal thermostat?
It is called a bi-metal thermostat because at its heart is a strip made of two metals with different expansion rates, which when heated begins to curve. This property is used to make a switch which opens with a temperature change.
What happens when the thermostat opens on a defrost heater?
The thermostat is wired in series with the defrost heater, and when the thermostat opens, the heater shuts off. You will have to remove any objects that are in your way such as the contents of the freezer, freezer shelves, icemaker parts, and the inside rear, back, or bottom panel.
How to check if a thermostat is cold?
Place each of the multitester's leads on a thermostat wire. When your thermostat is cold, it should produce a reading of zero on your multitester. If it is warm (anywhere from forty to ninety degrees Fahrenheit), then this test should produce a reading of infinity. If the results you receive from your test differ from the ones presented here, then you will need to replace your defrost thermostat.
How to test a defrost thermostat?
Before you begin to test your defrost thermostat, make sure you disconnect the appliance's power supply. The easiest way to do this is to unplug the unit from the wall. Alternatively, you could trip the appropriate switch in the circuit breaker panel, or you could remove the appropriate fuse from your home's fuse box.
What to do if you don't feel you have the skill or ability to complete a repair?
Consult with an appliance repair technician if you do not feel you have the skill or the ability to successfully complete this repair.
Can you remove plastic molding from a refrigerator?
Some older refrigerators may require that you remove a plastic molding before you can gain access to the freezer floor. Exercise caution when removing the molding, as it does break fairly easily. You could try warming it with a warm, wet towel first. There are two wires leading from the thermostat.
How to remove wires from thermostat?
Pull the defrost thermostat free of its retainer clip and remove the electrical wires from its terminal. In most cases, the wires are connected with push-on terminals. In high-end appliances, the wires may be secured with screws. In the latter case, remove the screws by turning them counterclockwise.
What is a defrost thermostat?
The defrost thermostat, a bi-metallic switch, controls the temperature rise in the freezer compartment during the defrost cycle. Once the temperature reaches a preset level, the defrost thermostat opens, shutting off electric current to the defroster heating elements, much as your home's heating thermostat shuts down the furnace once ...
What happens if your thermostat is not working?
A malfunctioning thermostat can keep the defrost heating elements from turning on or keep them on too long, causing heat damage or even a fire.
How to remove thermostat plates?
The plates covering the thermostat may be held in place by screws or clips. To remove the plates, remove the screws or release the clips with a small screwdriver. In the case of a molding, use care not to crack it when removing it.
What does 0.000 mean on a thermostat?
The LCD on the meter will display “0.000” if the cold thermostat is in the closed position. The defrost thermostat should be in the closed position when cold. Check to be sure the thermostat is opening at the correct temperature by placing it in water and slowly heating the water.
How to test a multimeter with a red jack?
Set the function selector switch on the digital multimeter to its R x 1 scale. Plug the red test lead into the red jack, marked "VmA" -- volts milliamperes. Plug the black test lead into the black jack marked "COM." Attach the test probes to the terminals on the thermostat.
Where is the thermostat on a refrigerator?
In side-by-side refrigerator-freezers, the thermostat usually is at the back of the compartment. With top-mounted freezers, the thermostat usually is under the compartment's floor plate or behind a molding at the front edge of the floor plate. With bottom-mounted freezers, the thermostat usually is under the compartment's roof plate.
What is bi metal strip?
The bi-metal strip is clipped onto the evaporator coils and is designed to regulate the defrost coil temperature. If it is not functioning properly you may notice ice buildup preventing air flow (and preventing proper refrigeration), or more rarely the freezer side may get too warm during the defrost cycle. Materials:
What to do if there is frost build up on refrigerator?
If there is frost build up you may need to replace the Bi-Metal Defrost Thermostat or the Defrost Heater. If you do not have a frost build up you need to listen to see if the fan at the back of the freezer is kicking on. The Evaporator Fan circulates air over the refrigerator coils. These coils will convert the heat into cool air, ...
Why do I need a bi-metal defrost thermostat?
If you have ice building up in your freezer, or if your freezer is getting too warm during the defrost cycle you may need to replace the bi-metal defrost thermostat. The function of the defrost bi-metal thermostat is to clip onto the evaporator and protect your evaporator from overheating during the defrost cycle.
How many Ohms should a thermistor read?
With the thermistor submerged is a glass full of ice water, the sensor should be very close to 32°F which should read approximately 16.3K Ohms.
Where is the frost buildup on a freezer?
If there is frost buildup on the evaporator coils, which are behind the back wall of the freezer section , that is a good indicator that there is an issue with the defrost thermostat, the defrost heater, or the defrost control board.
Where is the evaporator coil located?
2: Remove the panel covering the evaporator coils. It's located inside the fridge, on the freezer side.
What happens if a fan is not running?
These coils will convert the heat into cool air, which is then circulated into the fresh food section If the fan is not running then the air will not circulate. It is also a good idea to check the gasket around the door. If there are gaps or if it is not sealing properly it will let warm air in.
How to know if your fridge is frozen?
If all the items in your fridge are frozen, check the thermostat to know if you set it to the highest level. In the same way, if your food items are getting spoiled due to high temperature in the fridge, check if the thermostat is set to the lowest level. Get good access to the thermostat.
Why is my refrigerator not cool enough?
When your fridge is not cool enough: If you notice that the food items in the refrigerator are not as cold as you expected them to be or that the temperature in your refrigerator is not appropriate, there might be a fault in the thermostat because the thermostat regulates the temperature in the refrigerator and also keep things chilled.
Why does my refrigerator stop working?
When the gas leaks out, the pressure in the thermostat control body drops to nothing, making the compressor think that the refrigerator is cool enough and stops by itself.
What temperature should a refrigerator be when it's cold?
When there’s a fluctuation in the refrigerator temperature: The normal temperature for keeping food items cold is usually between 320F to 400F.
Why is my refrigerator getting cold?
When your refrigerator is getting unusually cold: If the food items are getting frozen within the other compartments, that’s a sign of a thermostat malfunction.
What happens when the thermostat feels too much heat?
And when the thermostat feels too much heat, it lets electricity flow, activating the compressor.
How long to leave refrigerator on to adjust temperature?
Then, plug the refrigerator back into the wall outlet. Set the refrigerator and freezer controls to the desired setting. Leave the refrigerator for 24 hours to adjust to a stable temperature.