How Does a Refrigerator Ice Maker Work?

The Basic Components of an Ice Maker

An ice maker may seem simple, but it’s actually a finely-tuned, rugged device with a few key components that work together to ensure a steady supply of ice. Here’s a breakdown of its essential parts:

Water Valve

The water inlet valve controls the flow of water into the ice maker. It connects the home’s water supply to the fridge and only opens when it receives a signal from the ice maker’s control mechanism.

Some refrigerators use a main water valve to allow water flow into the fridge and a second water valve to supply water to the ice maker.

Ice Mold

The ice mold is the tray where water is poured and frozen into cubes. It’s usually shaped to make small, standard-sized ice cubes.

When it comes to refrigerator ice makers, there are a variety of ice mold designs, each using a different method to release ice cubes once they’re frozen.

The two main categories of ice molds are flexible ice trays, which require manual twisting, and rigid ice molds, which use mechanical arms or other ejector mechanisms.

Flexible Ice Molds

These are a common in modern refrigerators. Flexible ice molds’ straightforward design are typically installed in small freezer compartments located in the refrigerator compartment of French door fridges.

These molds are made from a pliable material like silicone or plastic, allowing ejection components to twist and bend the tray to release the ice. By simply twisting or flexing the tray, you break the bond between the ice and the mold, freeing the cubes with minimal effort. While this design is convenient for ice-making, it often doesn’t produce the volume of ice that fixed ice mold icemakers can deliver.

Rigid Ice Molds

In contrast, Rigid Ice Molds are the original design in automatic refrigerator ice makers. Made from durable metal or hard plastic, these molds are fixed in place and rely on a more complex ejection mechanism to release ice. Typically, a heating element briefly warms the mold, loosening the ice cubes just enough for a set of ejector arms or scraper blades to push the cubes out.

The scraper arms rotate through the ice mold, sweeping the ice cubes from their compartments and dropping them into the ice bin below. This design is ideal for automatic ice maker operation, as it is rugged and dependable.

Ice Maker Thermostat or Thermistor

This temperature sensor monitors the freezing point of the water, triggering the next phase of the process once the ice reaches the right temperature (typically less than 5-degrees F).

A thermostat is a switch in a rigid ice mold system that allows the heater to warm the mold and ice cubes to prepare for the ejection process.

A thermistor is an electronic temperature sensor that sends signals to an electronic control board to indicate the cubes are frozen and initiate the ejection process.

Ejector Blades or Flex Tray Motor

Ejector blades push the ice cubes from the mold the ice bin after the cubes are warmed and released by the heater.

The flex tray motor tilts the tray and twists or flexes the tray once the ice is fully frozen. This flexing action loosens the ice cubes from the mold, causing them to fall out and drop into the storage bin below.

Ice Bin

After the cubes are released from the ice mold, they drop into the storage bin, where they wait to be dispensed.

Many ice bins house an auger mechanisms that helps push or guide the stored ice cubes down through the ice chute during the dispensing process.

Step-by-Step: How an Ice Maker Produces Ice

Now that we know the parts, let’s dive into the process from start to finish:

1. Filling the Mold

When you turn on the ice maker, it signals the water valve to open, allowing a small amount of water to flow into the ice mold. The water is then evenly distributed into the mold’s individual compartments to make cubes.

2. Freezing the Water

Once the mold is filled, the thermostat steps in to monitor the temperature of the water. The freezing process begins as the water cools to 32°F (0°C), slowly transforming into solid ice. Depending on your freezer settings and the type of fridge, this process can take anywhere from 45 minutes to an hour.

3. Detecting Ice Readiness

The thermostat or thermistor triggers the next step once it detects that the water has fully frozen.

In an ice maker with a rigid ice mold, tripping the thermostat sends electric current to a heating element beneath the ice mold, which gently warms the mold, loosening the ice cubes enough for easy removal.

For a flex-tray ice maker, the thermistor sends a signal to the ice maker control board to initiate the harvest cycle to dump the frozen cubes into the ice storage bin.

4. Ejecting the Ice Cubes

Ice Maker with a Rigid Mold

With the ice loosened, the ejector blades rotate to push the cubes out of the mold and into the ice bin. These blades sweep across the mold, clearing it out to make room for the next batch of ice.

Flex-Tray Ice Maker

When the control senses that cubes are frozen, the motor first tilts the flexible tray and then twists the mold to release the cubes and drop them into the ice storage bin.

The motor then rotate the flexible mold back to the level home position so the mold is ready to be filled with water to produce the next batch of ice.

5. The Cycle Repeats

The ice maker system checks the level in ice cubes in the ice bin using a mechanical sensing arm or an infrared level-sensing beam. If the ice bin has room for more ice, the entire cycle starts again.

What Happens When the Ice Bin is Full?

If the ice cube level sensing system detects that the ice bin is full, the ice maker assembly will fill with water and produce a new batch of cubes in the ice mold. The control won’t initiate the harvest or ejection portion of the cycle until the ice bin level sensor detects that the ice bin has room for the frozen cubes in the ice mold.

Troubleshooting Common Ice Maker Issues

Despite their impressive reliability, ice makers can occasionally run into issues. Here are a few common problems and tips for troubleshooting:

Ice Maker Not Producing Ice

An ice maker can stop working for a variety of reasons. Water supply problems, temperature issues in the freezer or ice room, or ice maker system component failures can prevent ice production.

Check the Ice Mold for Water

First, look for water or frozen ice cubes in the ice mold. Use a light and mirror if necessary to see inside the ice mold.

If the ice mold is empty, manually fill the ice mold and see if the ice maker system ejects the ice cubes when they’re frozen. If the ice maker ejects the frozen cubes, then the failure is almost certainly caused by a water supply problem.

Check the water fill tube above the ice mold to see if it’s frozen. If it is, you may be able to fix the ice production problem by defrosting that fill tube. Blowing warm air on the tube using a hair dryer on a low heat setting will often do the trick.

If you’re unable to defrost the frozen fill tube on your own, schedule refrigerator repair service to have a technician fix the problem.

If the fill tube isn’t frozen, a failed ice maker water valve, bad ice maker control or wiring failure could be preventing the ice maker from filling.

Measure Freezer or Ice Room Temperature

If the ice mold is full of ice but the ice make module isn’t dumping the ice, the freezer compartment or ice room temperature may not be cold enough. The thermostat or thermistor won’t initiate the harvest function unless the sensor detects that the temperature at the ice mold is less than 5-degrees F.

If the freezer and refrigerator isn’t cooling properly, troubleshooting a freezer temperature problem will sometimes fix the ice maker failure. Cooling problems in a fridge are often caused by defrost system problems. Follow the troubleshooting tips in this video to resolve cooling problems in the freezer and refrigerator:

Schedule Repair Service

If these troubleshooting tips don’t help you find and resolve the cause of the ice maker failure, schedule refrigerator repair service to have a Sears Home Services technician visit your home and fix the ice maker.

Small or Misshapen Cubes

This can indicate a low water flow, which may be caused by a partially clogged filter or a kinked water line. Replacing the filter or adjusting the water line can usually fix this.

Odd Tasting Ice

If your ice tastes unusual, it may be time to change your water filter or clean the ice bin.

Over time, the bin can absorb odors from other foods in the freezer, affecting the taste of the ice. Discard all of the ice in the ice bin and let the icemaker fill the ice bin with fresh ice cubes.

To prevent the problem from returning, wrap foods stored in the fridge well or store them in air-tight containers inside the fridge and freezer.

Tips for Keeping Your Ice Maker in Top Shape

• Replace the Water Filter Regularly: Aim to change the water filter every 6 months to keep water flowing smoothly and to avoid any buildup that might affect the taste of your ice.
• Keep the Freezer Temperature Consistent: Set your freezer to the ideal temperature (0°F) for optimal ice production.
• Clean the Ice Maker and Bin: Wipe down the ice maker and ice bin occasionally to prevent odors and maintain ice freshness.
• Schedule Annual Professional Refrigerator Maintenance: Scheduling professional refrigerator maintenance yearly will help you keep your ice maker and refrigerator in top shape and working efficiently.

Regular maintenance and cleaning will help keep your ice maker in great shape for years. And if anything goes wrong, don’t hesitate to call Sears Home Services for a professional solution.