Appliance Repair Industry Terminology

Aftermarket Part

A non-OEM replacement component produced by a third party that fits and functions like the original. Cheaper and sometimes more available, but may affect warranty or performance depending on quality.

- We can quote an aftermarket pump to lower the repair cost. - The extended warranty requires OEM, not aftermarket parts. - Our policy allows aftermarket only on out-of-warranty jobs.

Agitator

The vertical post with fins in many top-load washers that oscillates to move laundry. Often includes components like dogs, cams, and a bolt securing it to the transmission shaft.

- The washer’s agitator dogs are worn and need replacement. - This model uses an impeller instead of a two-piece agitator. - Clothes aren’t moving because the agitator is stripped.

Airflow Restriction

A blockage or reduced flow of air in vents, ducts, or internal passages that degrades appliance performance (common in dryers, refrigerators, and dishwashers). Caused by lint, kinks, frost, or dirty coils.

- Long dry times point to a dryer vent airflow restriction. - Frosting on one side suggests an airflow restriction at the damper. - Clean the condenser coils to reduce airflow restriction.

Bake Element

The electric heating element at the bottom of many ovens used for the bake function. Failure causes no or uneven baking; tested with continuity.

- No heat in bake but broil works; likely the bake element. - The element is open; continuity test failed. - Replace with the correct wattage bake element for this model.

Bill of Materials (BOM)

A comprehensive list of parts and assemblies for a specific model, often presented with exploded diagrams and part numbers to guide accurate identification and ordering.

- Pull the BOM to confirm the correct gasket part number. - The BOM shows a superseded control board. - Check the BOM’s exploded diagram before ordering.

Bimetal Defrost Thermostat

A clip-on thermostat in many refrigerators that opens when the evaporator warms and closes when it’s cold, enabling defrost heater operation. Also called a defrost bimetal.

- The bimetal opened too early, so the coil never defrosts. - Replace the defrost thermostat along with the heater. - It reads closed when cold and open when warm.

Brazing

High-temperature joining of metal tubing (e.g., copper) with a filler metal. Used in sealed-system repairs; requires nitrogen purge to prevent oxidation and proper safety practices.

- Braze the filter drier with a nitrogen purge. - Use silver-bearing rod for the copper-to-brass joint. - De-energize and evacuate before brazing the sealed system.

Capillary Tube

A very small-diameter tube that meters refrigerant into the evaporator. Restrictions or contamination cause poor cooling and abnormal frost patterns.

- A restricted cap tube causes a weak frost pattern. - The unit cools after clearing debris at the capillary entrance. - Charge by weight after replacing the cap tube.

Cash on Delivery (COD)

Payment collected from the customer at the time of service, commonly for out-of-warranty jobs. Often includes diagnostic fees and labor; parts may be prepaid.

- This is a COD call; collect the diagnostic fee on arrival. - Warranty jobs aren’t COD; we bill the provider. - COD pricing includes the trip charge and labor.

Compressor

The heart of a sealed refrigeration system that compresses low-pressure vapor into high-pressure vapor, driving the refrigerant cycle. Can be fixed-speed or inverter-driven.

- The compressor is shorted to ground. - Inverter compressor draws variable current by design. - Locked rotor; we measured an LRA spike and no start.

Continuity

An unbroken electrical path, verified with a multimeter. Technicians test continuity to confirm if fuses, elements, switches, and windings are intact.

- The thermal fuse has no continuity; it’s blown. - Verify continuity on the door switch before replacing parts. - Element shows continuity but is shorted to chassis.

Control Board (Main PCB)

The appliance’s central electronic board managing inputs, outputs, and logic. Failures can mimic sensor or motor issues; diagnosis relies on schematics and test points.

- The control board isn’t sending voltage to the heater relay. - We’ll flash the latest firmware to the main PCB. - Check the tech sheet for control board pinouts.

Diagnostic Fee

A fixed charge for evaluating and identifying the problem, often credited toward the repair if approved. Distinct from trip or labor charges.

- The $99 diagnostic fee is applied if you proceed with repair. - We charge a separate diagnostic fee for a second appliance. - Warranty provider caps our diagnostic fee at $85.

Direct Spark Ignition (DSI)

A gas ignition system that uses a spark to ignite burners or ovens directly, then confirms flame via a sensor. Common in modern gas ranges and ovens.

- The DSI module isn’t sensing flame; it shuts gas off. - Replace the DSI harness with the updated kit. - Clean the burner for reliable DSI ignition.

Diverter Valve

A valve or motorized mechanism that directs water flow to different paths, such as switching dishwasher spray zones or washer recirculation and drain functions.

- The dishwasher diverter sticks; only the lower arm sprays. - Listen for the diverter motor indexing during wash. - Replace the sump-and-diverter assembly to fix leaks.

Door/Lid Lock Switch

A safety interlock that confirms the door/lid is closed and locked before high-speed or hazardous operations. Failure prevents spin, heat, or start.

- Washer won’t spin because the lid lock won’t engage. - The door lock error persists; check the strike and switch. - Replace the lock and update the control per TSB.

Drain Pump

An electric pump that removes water from washers and dishwashers. Failures include blockage, impeller damage, or electrical faults.

- The washer won’t drain; the pump is jammed with coins. - Check for 120V at the drain pump during the cycle. - Replace the pump and clear the filter housing.

Dryer Vent Backpressure

Resistance to airflow in a dryer exhaust system due to lint buildup, long runs, or improper ducting. Causes overheating, long cycles, and safety risks.

- Excess backpressure causes long dry times and heat cycling. - Replace the foil flex with rigid to reduce backpressure. - The booster fan lowered vent backpressure significantly.

Error Code

A coded fault message displayed by an appliance to indicate specific failures or conditions. Decoded via tech sheets or service manuals.

- F9E1 indicates a drain problem per the tech sheet. - Record the error codes before power cycling the unit. - Run diagnostics to clear latched error codes.

ESD (Electrostatic Discharge)

A sudden flow of static electricity that can damage electronic components. Controlled with grounding straps, mats, and ESD-safe packaging.

- Use an ESD strap when handling the UI board. - ESD damage caused the board’s microcontroller to fail. - Store boards in ESD-safe bags only.

Evaporator

The cold heat-exchanger coil where refrigerant absorbs heat and evaporates. Proper frost patterns and airflow are critical for performance.

- Only the first few coils frost; weak evaporator pattern. - A block of ice on the evaporator points to defrost failure. - Check the evaporator fan for airflow across the coil.

Evaporator Fan Motor

The fan that circulates air across the evaporator and through compartments. Failure causes temperature imbalance and poor cooling.

- Freezer’s cold, fridge is warm; fan isn’t running. - The motor is noisy; replace with the updated part. - Verify 12V DC supply on inverter-style fan motors.

Extended Warranty

A service plan beyond the manufacturer’s warranty, often administered by third parties. Defines coverage, authorization, and claim procedures.

- The extended warranty covers parts but not cosmetic damage. - We need pre-authorization from the warranty company. - Claim labor rates follow the extended warranty schedule.

First-Time Fix Rate (FTFR)

The percentage of service calls resolved on the first visit. A key efficiency metric influenced by diagnostics, parts availability, and training.

- Stocking truck parts boosted our FTFR this quarter. - FTFR drops when we skip pre-diagnosis. - KPIs include FTFR and average ticket size.

Flat-Rate Pricing

A pricing model where each repair is billed at a set rate based on standardized labor times, rather than actual hours worked.

- We price by the Blue Book flat-rate, not time-and-materials. - Flat-rate reduces haggling and improves ticket consistency. - Complex jobs may need add-on flat-rate codes.

Flame Sensor

A device that confirms the presence of flame in gas appliances (dryer, oven, furnace). If no flame is detected, the system cuts gas for safety.

- The flame sensor is dirty; the burner shuts off early. - Replace the sensor if it doesn’t prove flame. - Clean the sensor rod to restore ignition reliability.

Float Switch

A switch that opens or closes based on water level, preventing overfill or signaling drain/fill operations in dishwashers and some washers.

- Dishwasher won’t fill; the float is stuck in the up position. - Test the float switch continuity when lifted. - Clean debris from the sump near the float.

Frost Pattern

Visual distribution of frost on the evaporator used to diagnose sealed-system health, airflow, and defrost issues.

- A full, even frost pattern suggests proper charge. - A ball of ice at the inlet points to a restriction. - No frost indicates compressor or sealed-system failure.

Gas Valve Solenoids

Electromagnetic coils that open the gas valve in gas dryers. Heat-related failure leads to intermittent burner operation after initial ignition.

- Dryer heats then goes cold; coils are failing when hot. - Replace both gas valve solenoids as a set. - Coils measure in spec but fail under load.

GFCI

Ground-Fault Circuit Interrupter receptacle or breaker that trips when it detects current leakage to ground, enhancing safety in wet locations.

- The fridge trips the GFCI; use a dedicated circuit. - Code requires GFCI near the sink for the disposal. - Nuisance GFCI trips point to leakage current issues.

Gross Margin

Revenue minus cost of goods sold (COGS), expressed as a percentage. Indicates profitability before overhead like payroll and dispatch.

- Our parts markup improved gross margin this month. - Track gross margin by job type and technician. - Flat-rate pricing stabilized gross margins.

Heating Element

A resistive component that converts electrical energy into heat. Found in dryers, ovens, and dishwashers (for drying/boost heat).

- The dryer’s element is shorted to the housing. - Oven underheats due to a weak bake element. - Measure element resistance against the spec sheet.

High-Limit Thermostat

A safety thermostat that opens when temperature exceeds a limit, protecting against overheating in dryers, ovens, and microwaves.

- The high-limit opened due to poor airflow. - Replace the high-limit and fix the vent restriction. - Verify resettable vs one-shot high-limit types.

Ice Maker

An assembly that automates ice production: fill, freeze, harvest, and refill. Issues include fill blockages, ejector failures, and faulty mold heaters.

- Harvest arm stalls; replace the ice maker assembly. - Fill tube is frozen; no water to the ice maker. - Test mode cycles the ice maker through harvest.

Igniter (Glow Bar)

A hot-surface igniter used in many gas ovens. It draws current to heat and help open the gas valve; weak igniters fail under load.

- Weak igniter glows but won’t open the gas valve. - Measure igniter current draw against spec. - Replace the igniter; avoid touching the carbide tip.

Inventory Turnover

How many times inventory is sold and replaced in a period. Higher turnover indicates efficient parts stocking and capital use.

- Truck stock review increased inventory turnover. - Slow movers hurt our turnover and cash flow. - Balance FTFR with optimal inventory turnover.

Inverter Compressor

A variable-speed compressor driven by an inverter board for efficiency and precise temperature control. Requires different diagnostics than fixed-speed units.

- Variable speed is normal; compressor noise is steady. - Diagnose the inverter board before condemning the compressor. - Measure DC supply and PWM signal to the inverter.

Job Costing

Tracking all costs (parts, labor, travel, overhead) by job to measure profitability and inform pricing and process improvements.

- Accurate job costing revealed low-margin warranty work. - Include travel time in job costing. - Job costing guides pricing updates and training.

KPI (Key Performance Indicator)

Quantifiable metrics used to gauge performance, such as first-time fix rate, average ticket, parts usage, callbacks, and customer satisfaction.

- Our KPIs include FTFR, callback rate, and NPS. - Review KPI dashboards in the Monday meeting. - Technicians see KPIs in the FSM app.

Labor Rate

The price charged per unit of labor time or embedded in flat-rate schedules. Varies by market, brand, and warranty agreements.

- We’re updating the labor rate for premium brands. - Warranty labor rates differ from COD rates. - The flat-rate book normalizes labor rate variations.

Magnetron

The microwave component that generates microwave energy. Diagnosed alongside HV transformer, diode, and capacitor; requires strict safety protocols.

- Loud hum and no heat suggest a failing magnetron. - Verify HV components before replacing the magnetron. - Discharge the capacitor; microwave HV is dangerous.

Manifold Gauge Set

Tool with high- and low-pressure gauges and hoses for measuring and servicing refrigeration systems. Use appropriate equipment and best practices for refrigerant type.

- Connect the manifold to check pressures on R134a units. - Use hydrocarbon-rated tools on R600a systems. - Pull to 300–500 microns after repair.

Multimeter

A handheld instrument for measuring voltage, current, resistance, and continuity. Essential for safe, accurate electrical diagnostics.

- Set the multimeter to AC volts before testing line. - Measure thermistor resistance and compare to the chart. - Use diode mode for testing HV rectifiers.

Nitrogen Purge

Flowing dry nitrogen through tubing during brazing to prevent oxidation and internal contamination; also used for pressure testing sealed systems.

- Purge at low flow while brazing to prevent scale. - Pressure test with nitrogen before evacuation. - Use a two-stage regulator for precise flow.

OEM (Original Equipment Manufacturer)

Parts made by the original manufacturer or its authorized suppliers, meeting design specifications and typically required for warranty compliance.

- The OEM board includes the updated relay. - Warranty jobs require OEM parts only. - OEM gaskets fit better than some aftermarket options.

Ohm’s Law

Electrical relationship V=IR linking voltage (V), current (I), and resistance (R). Fundamental for diagnosing circuits and predicting behavior.

- Calculate expected current draw using Ohm’s Law. - Voltage drop explains slow motor per Ohm’s Law. - Use Ohm’s Law to size test loads.

Overload Protector

A thermal device, often part of a compressor start assembly, that opens when excessive current/heat is detected to protect windings.

- The compressor overload is opening from overheating. - Replace the PTC and overload as a kit. - Check amp draw that trips the overload.

Parts Markup

The pricing strategy that sets retail parts price above cost to cover overhead and profit. Often tiered by cost or category.

- Standard parts markup is 2.5x on COD jobs. - Adjust markup for specialty or non-returnable boards. - Markup policy impacts gross margin and cash flow.

Pressure Switch

A sensor that detects pressure to infer water level or airflow. Traditional models actuate a switch; modern ones provide analog signals.

- The washer overfills; pressure switch hose is off. - Blow through the hose to clear soap residue. - Verify analog pressure sensor output to the board.

R600a (Isobutane Refrigerant)

A hydrocarbon refrigerant widely used in modern refrigerators. Efficient and low GWP but flammable (A3); requires certified tools and procedures.

- R600a is flammable; follow A3 safety procedures. - Charge by weight with a precision scale. - Use a recovery unit rated for hydrocarbons.