Expansion vessel
Boiler expansion tank · Expansion reservoir · Pressure balancing
Accommodates heating water expansion. Pressure fluctuations alone do not prove vessel failure; the appliance needs assessment.
Related service and guide ↗SERVICE TERMS
Understand parts and service work.
Learn common service terms in plain language. Use the symptom guide for your complaint and the relevant service page for the scope of work.
Choose a topic
Boiler and heating system
Heat exchanger
Primary exchanger · Plate exchanger · Boiler heat transfer
Transfers heat to water. Component layout varies by model; hot water problems alone do not justify exchanger replacement.
Related service and guide ↗Circulation pump
Boiler pump · Heating pump · Water circulation
Helps circulate heating water. Poor heating requires assessment of the pump, settings and system conditions together.
Related service and guide ↗Diverter valve
Three-way valve · Hot water switching · Heating circuit
Directs water between operating circuits in applicable appliances. Function and construction depend on the model.
Related service and guide ↗Temperature sensor
NTC sensor · Heat sensor · Boiler temperature sensing
Provides temperature information to the control system. Assessment requires measurements and model-specific fault information.
Related service and guide ↗Boiler control board
Electronic board · Main board · Boiler board fault
Manages appliance control functions. A non-working boiler needs diagnosis before attributing the fault to its board.
Related service and guide ↗Heating system strainer
Boiler filter · Heating filter · Sediment strainer
Helps retain circulating particles. Inspection and cleaning scope depend on the heating system configuration.
Related service and guide ↗Burner and ignition
Combustion assembly · Ignition electrode · Flame sensing
Components involved in combustion and flame control. Cleaning or adjustment requires technical assessment rather than user intervention.
Related service and guide ↗Fan and flue system
Boiler fan · Flue connection · Combustion gas outlet
Air and combustion gas handling depend on appliance type. Fan or flue symptoms require professional assessment of safe operation.
Related service and guide ↗Condensate and drainage
Condensing boiler · Condensate outlet · Boiler trap
Condensing appliances discharge water through an appropriate drain. A condensate problem differs from a heating water leak.
Related service and guide ↗Radiator balance and air
Radiator air · Radiator valve · Heating balance
Heat distribution depends on valves, circulation and system conditions. Cleaning alone does not resolve every imbalance.
Related service and guide ↗Room thermostat and scheduling
Wireless thermostat · Wired thermostat · Heating timer
Helps manage heating demand by room temperature or schedule. Appliance compatibility and connection method need checking.
Related service and guide ↗AC and installation
AC drainage
Drain hose · Condensate drain · Drain line
Removes condensate. Water leakage assessment considers the line condition and installation.
Related service and guide ↗AC air filter
Air filter · AC filter cleaning · Dust filter
Retains particles in the airflow. Care method and interval depend on model instructions and use conditions.
Related service and guide ↗Evaporator and coil
Indoor coil · Heat transfer surface · AC coil
Surfaces involved in heat transfer. Dirt and airflow are assessed together; cleaning requires an appropriate method.
Related service and guide ↗Condenser and outdoor unit
Outdoor coil · Condenser cleaning · Heat rejection surface
Participates in refrigeration heat transfer. Outdoor airflow and surface condition matter during maintenance assessment.
Related service and guide ↗Fan and blower
Indoor fan · AC blower wheel · Fan motor
Moves air through the unit. Noise, vibration or weak airflow requires assessment of the fan and related conditions.
Related service and guide ↗Refrigerant and leak assessment
AC gas · Refrigerant leak · Refrigerant charging
The heat-carrying fluid circulates in a closed circuit. Suspected shortage requires cause assessment; not every cooling fault needs charging.
Related service and guide ↗Compressor and inverter
AC compressor · AC motor · Inverter control
Terms related to refrigeration and capacity control. A non-working outdoor unit requires measurements before a part decision.
Related service and guide ↗AC control board and sensors
AC main board · Temperature sensor · Indoor-outdoor communication
Electronic control and sensing components. Fault codes need brand and model context; board replacement is not an automatic remedy.
Related service and guide ↗Louvre and swing mechanism
AC flap · Air direction control · Swing motor
Controls airflow direction. A louvre movement issue differs from a fan that produces no airflow.
Related service and guide ↗Evacuation and pipework
Copper pipe · Pipe insulation · Installation evacuation
Installation work involving pipework and circuit preparation. Methods and requirements follow the appliance installation instructions.
Related service and guide ↗BTU and capacity selection
AC capacity · Room size · Heating and cooling load
Sizing considers area, insulation, sunlight and use together. Floor area alone does not determine the correct appliance.
Related service and guide ↗Defrost and operating modes
Defrosting · Heat cool dry · Fan mode
Heating, cooling, dehumidifying and fan modes serve different purposes. Some models temporarily change operation during defrosting.
Related service and guide ↗This dictionary does not diagnose faults. Parts and work depend on the appliance model and technical assessment.
Open the symptom guide ↗