Refrigeration Flashcards
Flow Meter
Measures refrigerant flow rate in kg/s or lb/min. Located in liquid line after receiver.
Malfunctions: Clogged filter (clean) or erratic readings (purge air/replace transducer). Parts: Rotameter, transducer, inlet/outlet ports.
Expansion Valve (TXV/EXV)
Regulates refrigerant flow into evaporator via pressure drop. Located between liquid line and evaporator.
Malfunctions: Stuck open (floods evaporator) or closed (no cooling). Check superheat! Parts: Thermal bulb, diaphragm, adjustment screw.
Pressure/Temperature Gauges
Monitors high/low-side pressures and temps. Located at service ports.
Malfunctions: Zero reading (broken sensor) or drift (recalibrate). Parts: Bourdon tube, sensor probe, display.
Evaporator
Absorbs heat, boiling refrigerant. Located after expansion valve.
Malfunctions: Frost (low airflow) or no cooling (blockage). Parts: Coils, fins, blower fan.
Drip Pans
Collects condensate. Located below evaporator.
Malfunctions: Leaks (clogged drain). Parts: Drain pan, outlet tube.
Dual Pressure Control
Safety switch for high/low pressure limits. Located on service ports.
Malfunctions: Compressor won’t start (test contacts). Parts: Diaphragm, adjustment screws.
Reversing Valve
Switches between heating/cooling modes. Near compressor.
Malfunctions: Stuck (check solenoid voltage). Parts: Solenoid coil, sliding piston.
Suction Accumulator
Prevents liquid floodback to compressor. Before compressor inlet.
Malfunctions: Slugging (fix TXV/charge). Parts: U-tube, oil return port.
Hermetic Compressor
Compresses refrigerant vapor. Central unit.
Malfunctions: Overheating (low charge) or no start (check capacitor). Parts: Motor, pistons, oil sump.
Receiver
Stores liquid refrigerant. After condenser.
Malfunctions: No flow (clogged screen). Parts: Inlet/outlet valves, sight glass.
Condenser
Rejects heat from refrigerant. After compressor.
Malfunctions: High pressure (clean coils). Parts: Coils, fins, fan.
Ammeter
Measures compressor current. Wired in series.
Malfunctions: No reading (check wiring). Parts: Current transformer, display.
Electronic Temperature Controller
Maintains set temperature. On control panel.
Malfunctions: Incorrect cycling (replace sensor). Parts: Microprocessor, relay outputs.
Mode Switch
Selects heating/cooling. On control panel.
Malfunctions: Mode not changing (broken contacts). Parts: Rotary selector.
Power Switch
Main on/off control. On control panel.
Malfunctions: No power (burnt contacts). Parts: Toggle mechanism.
Meter Read Switch
Selects displayed parameter. On control panel.
Malfunctions: No display change (worn contacts). Parts: Multiposition selector.
Electrical Test Strip
Provides measurement access. Near control panel.
Malfunctions: No continuity (tighten connections). Parts: Terminal blocks.
Check Valve
Allows one-way flow. In heat pump liquid line.
Malfunctions: Restricted flow (replace valve). Parts: Ball/spring mechanism.
Shutoff Valve
Isolates components. At service points.
Malfunctions: Leaks (replace seals). Parts: Valve stem, gasket.
Filter-Drier
Removes moisture/contaminants. Liquid line.
Malfunctions: Clogged (replace unit). Parts: Desiccant bag, filter screen.
Moisture Indicator
Shows refrigerant moisture. On liquid line.
Malfunctions: No color change (replace). Parts: Color-changing element.
Schrader Valve
Service port for gauges. High/low-side.
Malfunctions: Leaks (replace core). Parts: Valve core, protective cap.
