Refrigerators & showcases
53 Field cases
- Abnormal Superheat — Low / High Diagnosis
- Superheat Hunting — TXV Oscillation
- Superheat Cannot Be Measured — Gauge or Thermometer Reliability Failure
- Abnormal Subcooling — Low / High Diagnosis
- Zero Subcooling — Continuous Bubbles in Liquid Sight Glass
- PT Chart Usage — Pressure↔Temperature Conversion Diagnosis
- Refrigerant Type Cannot Be Identified — Missing Nameplate or Painted Over
- Manifold Gauge Connection Procedure — Standard Work Order
- Normal Operating Pressure Ranges — Reading Against Ambient Temperature
- Manifold Zero & Accuracy Calibration — Reliability Check
- Abnormally High Discharge (High-Side) Pressure — 4 Major Causes
- Abnormally Low Discharge (High-Side) Pressure — Diagnosis & Response
- Discharge Pressure Fluctuation — Pulsation, Oscillation, Cyclical Changes
- Compressor Short Cycling — Rapid ON/OFF Repetition
- Condenser Fan Short Cycling — Intentional vs Faulty Operation
- Refrigerant Overcharge — Symptoms, Diagnosis, Recovery to Spec
- Refrigerant Undercharge — Symptoms, Diagnosis, Leak Check
- Mixed or Wrong Refrigerant — Identify and Recover Immediately
- Refrigerant Recovery and Recharge Procedure — Standard Workflow
- Drain Trap / Line Freezing — Cold Environment Blockage
- New Refrigerants PT Chart — R-32 / R-454B / R-744 (CO2)
- Altitude Correction — Pressure Adjustment for Mountain/Highland Systems
- Subcooling Fluctuation — Hunting/Instability Diagnosis
- Confirming Overcharge with Subcooling — Most Reliable Diagnostic
- PT Chart — Glide refrigerants (R-407C / R-410A / R-454B) dew/bubble temperature difference in detail
- PT Chart — invalid below 0 PSIG (vacuum range), use micron/vacuum gauge instead
- Superheat near 0°C + suction line sweating/icing — Liquid Floodback emergency response
- Superheat behavior at low load — distinguishing normal from faulty
- Abnormal subcooling from condenser fouling/tube blockage — trim diagnosis
- System vacuum test with manifold gauge — procedure and pass criteria
- Short cycling — frequent ON-OFF after defrost
- Short cycling — aged thermostat or chattering contacts
- Short cycling — contactor or relay coil chatter
- Short cycling — low refrigerant charge causing low-pressure cutout/restart loop
- Suction pressure at low load — distinguishing normal from faulty (low load ≠ low charge)
- Abnormally high suction pressure — distinguish flooded, overcharge, compressor efficiency loss
- Discharge pressure pulsation — root causes and muffler/accumulator diagnostics
- Discharge line noise — pressure-based diagnosis vs simple listening
- Compressor bearing wear — vibration/noise/current/oil four-axis diagnosis
- Compressor motor overheat — internal overload (Klixon) tripping and root-cause diagnosis
- Compressor oil acidity test — using an Acid Test Kit and interpreting results
- Compressor fails to start — branching by hum, sustained LRA, or instant trip
- Heavy rumble/vibration noise — separating bearing wear vs mount failure vs system-side vibration
- Oil separator — operating principle, inspection points, common faults
- Oil return design — suction-line traps, riser velocity, double risers
- Reading the oil sight glass — normal vs faulty patterns and stage-by-stage interpretation
- Oil mist lubrication — operating principle, faults, and system loss mechanism
- Oil type mixing risks — mineral, POE, PAG, PAO and the compatibility matrix by refrigerant
- Refrigerant identifier kit — usage, result interpretation, and alternative identification methods
- Refrigerant cross contamination — system / recovery tank contamination scenarios and remedy
- Non-condensables — air/nitrogen entering the system, diagnosis and removal
- Refrigerant recovery equipment (machine, tank, scale) — use, maintenance, fault diagnosis
- Flammable refrigerants (R-32, R-454B, R-1234yf, R-290) — A2L/A3 classes, handling safety, recovery, work rules