Fridge Not Cooling But Freezer Works

作者: nicO (和另外3个贡献者)

Regular Maintenance

Consider performing regular fridge maintenance as a first step. Try these refrigerator maintenance steps.

This page varies from a similar problem, freezer not freezing, because this is the opposite set of symptoms — the freezer is freezing, and the refrigerator isn't cooling. Proceed with the fixes below if you feel you're in the right spot.

注意!

Before removing and replacing or continuity testing electrical components, power down the fridge. This will prevent damage to the components and prevent you from being electrocuted.

If the fridge is pulled away from the wall, remove the plug.
Otherwise, find the fridge’s circuit breaker in your breaker box and turn the circuit off.
Check that the lights are off in in the fridge when you open the door

Refrigerators perform best when located inside a home and at around 70°F (21°C). Locations considerably above this temperature like 90°F (31°C) affect the cooling capacity, and the fridge may not cool sufficiently.

When in an unheated garage where the temperature drops below 36 degrees Fahrenheit (2 degrees Celsius), the refrigerator may shut down and stop cooling. This can lead to food thawing and warming inside the insulated fridge, especially in the freezer portion.

Additionally, a fridge located in a warm room, under the sun, or near hot appliances like a range or oven, can experience difficulties cooling effectively.

The evaporator fan blows cold air around the freezer. While the freezer is more efficient when it is appropriately loaded with food, too much food or incorrectly placed food will block the vents and prevent proper temperature regulation. The refrigerator vents allow for airflow between the fridge and freezer compartments. Blocking these vents may result in many issues.

Locate your evaporator fan and move frozen items further away.
Unblock the vents. A rule of thumb for frost prevention is to stock enough food to fill the freezer while keeping an inch of space between the food and the walls.

If your refrigerator has a knob or dial that sets the temperature, check it out. Verify it is set on cold and hasn't been bumped or shifted positions. Your fridge should be set below 40 degrees Fahrenheit (4° C) and above 35°F (2°C). Use a thermometer if you don't have a digital thermostat display. The freezer should be around 0°F

A buildup of ice on the evaporator will cause uneven temperatures. The freezer may still be cold, but the fresh food compartment may start to warm up. If you have a dual evaporator refrigerator, with one in the freezer and one in the fresh food compartment, go to the evaporator in the fresh food compartment. The fresh food evaporator controls that portion, so you don't need to check the freezer unit.

To check on this, you will need to remove the evaporator cover in the rear of your freezer. If it doesn't come off easily, don't force it. You can try to run a Forced Defrost Cycle, but it might be easier to just manually defrost the unit.

Use a steamer to remove ice on the evaporator coils. Do not use a heat gun, and avoid a hairdryer, as you can inadvertently warp plastic components unless you use great care. Further, a steamer is faster.

If you don't have one, use large bowls of hot water placed in the bottom of the freezer.

In any event, make sure your drain tube is not plugged. This can be a cause of the buildup. Here's a link to more information on unplugging your defrost drain.

When you do these checks in the freezer, check the freezer door seals as well. Bad door seals will lead to excessive frost, which can turn into ice on the evaporator. Then the refrigerator doesn't get as cool because the evaporator fan doesn't circulate air through a chunk of ice.

If there is no ice buildup, go to the next step.

At the backside and bottom of your fridge is the condenser and its coils. Refrigerant passes through the coils which dissipates heat during the cooling cycle. As dust and debris pile onto the coils the fridge becomes less efficient the fridge must work hard to cool down.

Pull your fridge out and inspect coils.
- Your fridge may have an anti-tip bracket and can only be removed by pulling straight out from the wall.
Clean dust off condenser coils and fan with a stiff brush and vacuum.
Work carefully during this task and avoid bending or damaging the tubes.

Door seals are gaskets for your fridge, and as they age and fall apart, cool air escapes through the cracks in door seals.

Inspect your door seals, then clean or replace if necessary.

The condenser fan draws air over the compressor and through the condenser coils. If the fan motor isn't working normally, then the fridge won't cool properly.

If the condenser fan isn't working well, you will likely have problems in the freezer compartment, too, but depending on your fridge, it may just affect the fresh food (refrigerator) compartment.

Check the fan blade for physical obstructions
Rotate the fan by hand. If it doesn't spin freely, replace the motor.
If it spins freely, test the motor for continuity. Replace the condenser fan motor if the continuity test fails.

The evaporator fan draws air over the cooling coils and circulates this air within the fridge and freezer compartments. The evaporator fan should be running as long as the compressor motor is running. If your fridge only has one evaporator fan motor it's located in the freezer compartment. When the fan fails it won't circulate the cold air to the refrigerator. In this event, the freezer may still get cold while the refrigerator stays warm.

Check the fan blade for physical obstructions.
Rotate the fan by hand. If it doesn't spin freely, replace the motor.
If it spins freely, test the motor for continuity. Replace the evaporator fan motor if the continuity test fails.
An unusually noisy motor should be replaced as well.

The damper is a device that controls the flow of cold air from the freezer compartment to the fresh food compartment on single evaporator refrigerators. That air circulation depends on the evaporator fan working properly, so if you have already checked it in the step above; this is a good next step. If it fails in the shut position, your fresh food compartment will warm up.

Many dampers are motorized and controlled by the temperature control in the fresh food compartment, or the main control board on newer refrigerators. You can check to see if your damper motor has continuity, and also appropriate resistance values (300-500Ω is a likely range).

Another problem that prevents your fridge from getting cold enough is a faulty thermistor. The thermistor is a sensor that monitors the air temperature. It is connected to the control board. If the thermistor is defective, the refrigerator does not cool (or may cool continuously).

Grab a multimeter and continuity test the thermistor. Place the thermistor tip into a cup of ice water made from ice, water (just enough to cover the ice) and salt. You will need to find information on the resistance value expected for your refrigerator's various thermistors at 32°F (0°C). The most likely culprit is the thermistor located in your fresh food compartment (Refrigerator compartment).

Another possible cause is the defrost thermistor. This can keep the defrost cycle from running fully, allowing ice to build up, which will cause temperature problems in the refrigerator either because the evaporator in the freezer frosts up or because the fresh food compartment defrost is failing in a dual evaporator system.

If the thermistors test ok go on to the next item.

If the refrigerator is not cold enough, the temperature control board might be defective. The temperature control board provides the voltage to the fan motors and compressor. Usually, a sensor is more likely the problem.

If the capacitor has failed, the compressor will not be able to start and run as it should. Most newer refrigerators use a run capacitor, which stays in the circuit and improves the energy efficiency of the compressor. Some older refrigerators may have a start capacitor, which functions just at startup. These are not as common.

You may be able to tell what kind you have by looking at a couple of factors. Many run capacitors are polymer-type capacitors with a small rectangular block shape. There are cylindrical run capacitors, but they are less common (some LG fridges have them). The capacitance values of run capacitors tend to be smaller on refrigerators, something between 10 and 22µF (µF stands for microfarads, also abbreviated MFD).

A Typical Run Capacitor

Safely remove the capacitor and discharge with a discharge tool.

On smaller capacitors, you can use a screwdriver with an insulated handle to discharge it. But be careful as capacitors increase in size.

Test the capacitor with a capacitance meter; replace it if the value measured is outside the tolerance listed on the capacitor (usually +/- 5-10%).

A very quick functional check for a capacitor is to set your multimeter to the continuity function with the beeper on. Connect the capacitor to the leads for a few seconds. Then, swap the leads to the opposite terminals. If the capacitor is at least storing some charge, you should get a short beep. This will not tell you if the capacitance is correct, only that the capacitor will store charge.

When you replace a capacitor, get the exact type of the existing capacitor and the same capacitance value. You can safely use a capacitor with the same or higher voltage rating than the original.

If everything checks out, go to the next item.

The overload relay is a protection device in the compressor circuit and is often combined with the start relay. You can find it plugged directly into the side of the compressor. If the fans are running and your compressor won’t start, or if you hear a clicking sound from the unit follow the troubleshooting below. You probably will find that the freezer will not be working right either. It might point to other problems, like a refrigerant leak as the compressor struggles.

Check the overload relay for signs of overheating or arcing.
- This may be a hot module, burnt, or rattles when shaken.
Check for continuity with a multimeter.
- Flip the unit over and test again. If there's no continuity, replace the unit.

The start relay is a small device mounted to the side of the compressor. It provides power to the run winding, along with the start winding, for a split second at startup to help get the compressor going. If the start relay is defective, the compressor may run intermittently or not at all, and the refrigerator will not get cold enough. The start relay should be replaced if defective.

Test Start Relay with a multimeter. View the video above and verify if your start relay is functioning.
Replace relay if it fails the testing or has a burnt odor. Depending on your start relay, you may have to test the run capacitor and overload relay first and use a process of elimination. If the other two components pass continuity tests, and your compressor isn't starting, try replacing your start relay.

Excessive vibration and aging connections in the pressurized refrigerant loop can cause a refrigerant leak. There are a few ways you can check if this is the case.

Is the compressor continually running to keep the fridge cool? A low refrigerant pressure results in cooling problems such as the freezer being too warm. If the freezer's evaporator coils are not frosting over completely this also suggests a leak or a blockage in the cooling system. This will lead to a freezer that sort of works but the refrigerator will start to warm.

Inspect for oily residues on condenser coils and on or around the compressor. The refrigerant is mixed with oil which lubricates the compressor. Oil suggests a refrigerant leak.

Tilting or transporting a fridge on its side can cause a blockage. The lubricating oil at the bottom of the compressor can enter the refrigerant lines and cause the compressor to burn out. A blockage in the system can cause ice build-up on the other side of the restriction in the refrigerant flow path.

An appliance technician can measure the low and high side pressures of the sealed refrigerant system. The pressures will indicate if the amount of refrigerant is correct and also if there are any restrictions in the sealed system.