Fault diagnosis is the process of identifying and characterising a fault when a failure occurs. It is, therefore, an essential step to take before product-repair. In this study, we ask how conventional users diagnose faults in household appliances and how the design of these appliances facilitates or hampers the process of fault diagnosis.To investigate this we qualitatively analyse the content of iFixit's online repair forum for three products: kitchen blenders, vacuum cleaners, and refrigerators. First, we develop a conceptual analysis framework based on the literature. Second, using conventional content analysis, we correlate facilitating and hampering features with the appliances’ design. The process of fault diagnosis can be described by the subsequent actions of fault detection, fault location and fault isolation. Our results show that consumers detect faults by noticing five types of symptoms. Subsequently, two distinct diagnosis approaches can be distinguished. One follows a trial and error approach where the user performs diagnosis actions which usually result in replacing a potentially defective component until the symptoms disappear. The other occurs when the symptoms are error codes; the defective part can be more accurately identified, and the diagnosis is straightforward. The results also show that appliances are not designed to make fault diagnosis easy. Access to and visibility of components are often blocked, making fault isolation challenging. User manuals commonly lack relevant explanations, for instance when symptoms are different from error codes. Based on these findings, we propose a number of design recommendations to facilitate fault diagnosis for household appliance users.@en

This paper explores existing design strategies, guidelines and product features that enable functional recovery operations like repair, refurbishing or remanufacturing. A circular economy demands for products to be kept as valuable as possible for as long as possible. Therefore, recovery operations should be easy to perform in an efficient manner, which is influenced by product design. As a result of the literature review conducted, this paper presents a categorization of functional recovery guidelines for product design and identifies the need to plan for recovery at early design stages.@en

Today’s industrialized societies face the challenge of integrating economic activity with sustainable consumption. Prosperity has come hand in hand with environmental damage. Product lifetimes are decreasing and there is a rising demand for high-tech products for which no effective recycling is in place. Hence, the value from products is lost to waste. The current use and management of the Earth’s resources is unsustainable. The circular economy (CE) aims at slowing, closing, and regenerating the flow of goods and materials that enter the economic system. It posits retaining the value from products and encourages a shift to renewable energy resources. In this way, the CE will help reduce our current accelerated resource depletion. In particular, product repairs can help slow down the flow of goods. Repairing products provides an alternative to premature product replacement, and contributes to a significant reduction of waste. In this thesis, I look in detail at the process of fault diagnosis, one of the initial steps to be taken when repairing products. Fault diagnosis identifies the faulty component(s) or cause of failure in a malfunctioning appliance and is therefore essential for efficiently repair. It enables the time, cost, and skills required for the component repair to be established.@en

The process of fault diagnosis is an essential first step when repairing a product: it determines the condition of the parts and identifies the origin of failure. We report on how product users go through the process of fault diagnosis in consumer products and the influence of design features on this process. Two groups of 12 participants were asked to determine the fault in a defective product we supplied; the groups differed in their self-reported repair expertise. Four types of products were used for the study: a vacuum cleaner, kitchen blender, radio CD player, and coffee maker. During the experiment, the participants were asked to think aloud to explain their actions and understandings. Afterwards, they were interviewed regarding their experience. The results from the verbal and video analysis provided input for an updated framework of the diagnosis process, describing user actions at each diagnosis stage. Furthermore, we show that the way a product is designed and constructed (the positioning, accessibility, and visibility of relevant product components) has a significant influence on the success of the fault diagnosis. An important factor is user experience: product use facilitates signal recognition, while repair expertise facilitates disassembly. However, user experience is still less influential than the product’s design. Based on these findings, we propose a set of design guidelines to facilitate the process of fault diagnosis in consumer products @en

Product repairs are at the core of sustainable consumption and user manuals can play a relevant role in facilitating them. They are the accredited source of product information for end users and are therefore sought as an important means for the diagnosis and subsequent repair of household appliances. However, despite increasing societal demand for repairable products, few studies have been conducted on the extent to which manuals contribute to the fault diagnosis and subsequent repair process. In this study, we analysed current guidance provided by manuals for the diagnosis process, answering the research question: ‘To what extent do user manuals provide sufficient information to diagnose the most frequent faults in household appliances?’ We examined the diagnosis instructions provided in the user manuals of four different household appliances using data on the appliances’ most frequently failing components, and a framework that considers three steps towards a suc- cessful diagnosis: fault detection, fault location, and fault isolation. In total, we analysed 150 user manuals of 48 brands available on the European market. We show that manuals do not instruct the diagnosis of frequently failing components. They mainly refer to causes of failure and directly recommend corrective actions after fault detection. Thus, they rarely include a three-step fault diagnosis process to identify and isolate a faulty component. Based on these results, we have extended the framework for the process of fault diagnosis to include a step from cause identification to corrective action. Both routes, the component- oriented and the cause-oriented route in fault diagnosis, should be considered during the design of products for easy fault diagnosis, and should be included in future regulations that address product reparability@en