TXV Hunting — Temperature Swings
Walk-in cooler temperature keeps swinging — overshoots cold, then drifts warm, never settles. Customer says they already added charge and it did not help. Unit: Walk-in cooler, R-404A, TXV with external equalizer, remote condensing unit. This is a graded decision lab from Commercial Refrigeration / RAC — you choose each next check, readings fill in as you work, wrong turns are coached, and you are scored on cause, efficiency, safety and verification. It runs inside HVAC Technical Training — Paths A–D, about 14 minutes.
- Interactive decision labs
- Built by working technicians
- Path-based verifiable certificate
- Exam preparation only
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Where this lab sits
This is one module lab from Commercial Refrigeration / RAC. The full path builds the rest of the diagnostic sequence around it, each module ending in a graded lab like this one.
Studying for an exam too?
Free practice questions with explained answers, then come back to the labs. Exam preparation only — we do not issue EPA, NATE or other official credentials.
All diagnostic labs
- Residential No-Cool — Split System Not Cooling
- Residential No-Heat — Gas Furnace Short Cycling on Ignition
- Frozen Coil / Airflow Restriction
- Residential Over- and Undercharge — Poor Cooling Call
- Superheat / Subcooling Decision
- Condenser / High Head — Walk-in Cutting Out on High Pressure
- A2L Safe-Handling Decision (R-454B)
- Walk-in Cooler Not Holding Temperature
- Ice Machine Not Making Ice
- Reach-in / Prep Table Not Holding Temperature
- Walk-in Freezer Defrost Fault
- Natural Refrigerant Safe-Handling Decision
- Rooftop Unit Not Cooling
- RTU Economizer Stuck — No Free Cooling
- RTU High Static — Low Airflow and Poor Cooling
- RTU Gas Heat — No Heat / Ignition Fault
- RTU First Start-up Sequence