A closer look at common causes of failure
By the mechanical engineering team
While household appliances are essential for carrying out a wide range of everyday tasks, if and when they malfunction, some appliances carry a higher risk of causing significant damage than others—especially the ones that use water! Understanding how faulty household appliances can lead to water damage is one preventative measure that can help homeowners everywhere.
In fact, there are three water-supplied appliances that are particularly prone to causing major water damage when they stop working properly, namely dishwashers, washing machines, and modern refrigerators.
CEP Forensic has conducted an in-depth review of over 100 appliance-related loss claims which CEP services were required over the last few years. This study found that 20% of the claims, in residential buildings, were linked to refrigerator failures. By comparison, dishwashers and washing machines were responsible for 43% and 37% of water damage losses, respectively.
Common failures for those three appliances
No appliance is immune to unexpected failure. In some cases, the fault may lie with the manufacturer, such as a manufacturing defect or premature wear. As a reference, the following table presents the average lifespan of these appliances, based on data from the U.S. Department of Energy.[1]
In many cases, the installation itself can lead to leakage or premature failure of the appliance. Indeed, many losses are caused by the installer disregarding the instructions provided by the manufacturer. Common errors include improper levelling of a washing machine, incorrect installation of the drain hose, and improper selection of supply hoses.
Indeed, the water supply hose is by far the most frequent source of installation problems which lead to water damages. During inspections conducted by CEP, our forensic experts often noticed that the subject hose had been improperly screwed, was damaged, bent, or kinked. These are some of the reasons why water supply hoses are among the first components to be examined during our site visits. We also see that inappropriate hoses are in place; this is often due to the replacement of the original hose or when no hose had been provided with the appliance. For example, the installer may choose a hose designed for gravity drainage, when one rated for pressurized water supply should have been used. In such cases, the hose will often fail under pressure which, ultimately, causes water damage.
In addition to errors that may be made during factory assembly, or by the installer at the time of installation, misuse of the appliance by the user is also a common cause of premature failure. From time to time, an investigation will reveal that an incident had been caused by a washing machine drum overload; a clogged dishwasher filter, due to poor maintenance; or by the improper insertion of a water filter cartridge in a refrigerator equipped with a water and/or ice dispenser. Each of these situations can lead to failure and cause significant water damage. These situations are also the easiest to prevent and can nearly always be avoided by following the manufacturer’s instructions in the appliance’s user guide.
Let us now explore the common types of failures that can be specifically associated with a refrigerator, a dishwasher, or a washing machine, and which may result in water damage.
Refrigerators
Water damage related to refrigerators are observed on models equipped with a water and/or ice dispenser, because they are supplied with running water. In addition to the common failures mentioned above, incidents can occur due to problems related to specific components.
Consider, for instance, the water inlet valves that open to allow water flow to the distributor or ice machine every time there is a demand by the user. These components are highly utilized and, therefore, are subjected to several thousand cycles of activation during the lifespan of the appliance, making them prone to mechanical failure. These valves are designed to be in a normally closed (and therefore watertight) position. When they fail, the valve typically remains stuck in the partially open position, which can result in a continuous water leak from the distributor or ice maker.
Test setup for a refrigerator solenoid valve
Incorrect insertion of the water filter cartridge or the installation of a cartridge incompatible with the specific refrigerator model can also lead to water leaks. The following graphic outlines the various types of failures that CEP has identified on files involving refrigerators.
Dishwashers
For dishwashers, freezing of the water inside the water inlet valve is a common cause of failure. Freezing events typically occur when the dishwasher is installed against a poorly insulated exterior wall. During cold spells, heat loss through the building envelope can cause the air temperature under the appliance to drop below the freezing point, leading to the freezing of the water inside the supply hose. Since the water inlet valve is typically made of plastic, it is usually the weakest point of the water circuit, making it the first component to fail under the pressure buildup, which is caused by the expansion of the ice plug in the hose. Freezing events will cause cracking of the inlet valve housing, which results in a continuous water leak from the point of failure.
Failure of a dishwasher solenoid valve due to a freezing event
Washing machines
Based on our analysis, the most common cause of unexpected, and often premature, failure affecting washing machines is the malfunction of the water level switch. The function of this switch is to control the amount of water which is allowed to enter the drum.
Laboratory analysis of a water level switch
When the appliance fills with water, a small plastic tube connected to the bottom of the tub also fills with air. As the water level rises, it compresses the air in the tube; this increased air pressure travels up the tube to a pressure switch (the water level switch). When the pressure reaches a certain threshold, the switch trips and shuts off the inlet valve.
So, if a malfunction occurs with the pressure switch, it is possible that the inlet valve will remain open, causing an overflow of the drum and water damage to the home. The failure of this component can be caused by several factors, such as clogging of the hose or a disruption of the electrical signal.
In summary, while there are numerous risks associated with the use of household appliances, water-related losses in a residence can be significantly reduced by following the installation and maintenance instructions provided by the manufacturer in the user manual. However, if a loss does occur despite these precautions, you can always rely on the expertise of CEP’s forensic investigators to help you determine the exact cause of the failure and facilitate the handling of your insurance claim or your litigation.
[1] U.S Departement of Energy
*The graphics demonstrated in this article are from the data collected by Kevin Champagne, CEP.