Appliance Installation and Repair Flashcards

A resident reports their refrigerator is running but not cooling. After verifying the thermostat is set correctly and the unit has power, you check the back of the unit and find the condenser coils are heavily covered in dust and pet hair. What is the most likely reason for the cooling failure?

Answer: The dirty condenser coils are preventing proper heat dissipation.

Condenser coils are responsible for dissipating heat from the refrigerant. When they become insulated with a layer of dust, hair, and debris, they cannot release heat effectively. This reduces the refrigerator's cooling efficiency, causing it to run constantly while failing to maintain the set temperature.

When installing a new garbage disposal that will be connected to a dishwasher, what critical step must be performed on the disposal unit itself before attaching the dishwasher drain hose?

Answer: Removing the manufacturer's knockout plug from the dishwasher inlet.

Garbage disposals intended for use with a dishwasher have a sealed inlet port. This port is blocked by a small 'knockout plug' that must be removed with a tool like a screwdriver and hammer before the dishwasher drain hose is connected. Failing to remove this plug will prevent the dishwasher from draining, causing it to back up with water.

A technician is using a multimeter to test the bake element of an electric oven that is not heating. After safely disconnecting the oven from power and removing the element, what reading on the multimeter would indicate that the element is faulty and needs replacement?

Answer: A reading of 'OL' (Open Line) or infinite resistance.

A functional heating element should have a continuous internal circuit, which will show a specific resistance value (typically between 10-100 ohms). A reading of 'OL' (Open Line), infinite resistance, or no continuity indicates a break in the element's internal wiring, meaning it is burned out and cannot complete the electrical circuit to generate heat.

A resident states their top-loading washing machine completes the wash cycle but is left full of water. After verifying the lid switch is functioning, which of the following is the most likely and easily correctable cause?

Answer: A kinked or clogged drain hose.

A kinked, bent, or clogged drain hose is one of the most common reasons a washing machine fails to drain. This physically obstructs the path for the water to exit the tub. Before investigating more complex mechanical failures like the pump or transmission, the technician should always inspect the drain hose for simple obstructions.

Which of the following is a building code requirement for installing a clothes dryer vent duct to ensure safety and efficiency?

Answer: The total developed length of the duct run should not exceed 35 feet, accounting for bends.

Most building codes, including the International Residential Code (IRC), limit the maximum length of a dryer vent to 35 feet. This length must be reduced for each 90-degree bend (typically by 5 feet) and 45-degree bend (typically by 2.5 feet) to account for airflow resistance. Using rigid or semi-rigid metal ducting is required, and screens are prohibited on the termination as they trap lint, creating a fire hazard.

A newly installed dishwasher is turned on for the first time. The unit fills with water and appears to run, but after the cycle, the dishes are still dirty and there is standing water in the bottom of the tub. The garbage disposal is new as well. What is the MOST probable cause of this issue?

Answer: The knockout plug in the garbage disposal's dishwasher inlet was not removed.

When a dishwasher drains into a garbage disposal, a knockout plug inside the disposal's dishwasher connection port must be removed during installation. If this plug is left in place, it completely blocks the dishwasher's drain hose, preventing it from expelling water. This will cause the dirty water to back up into the dishwasher tub at the end of the cycle.