Free interactive diagnostic labs
One decision on screen at a time. Wrong turns get coached, not just marked. You do not finish until the root cause is confirmed and the repair is verified — exactly like the labs inside the paid paths.
- Interactive decision labs
- Built by working technicians
- Path-based verifiable certificate
- Exam preparation only
- Worldwide online
Commercial Refrigeration / RAC
~15 min
Walk-in Cooler Not Holding Temperature
Walk-in cooler is running but product temperature is rising. Box is at 48°F, setpoint 35°F.
Start the lab →Commercial Refrigeration / RAC
~14 min
Ice Machine Not Making Ice
Ice machine is running but producing little or no ice. Bin is nearly empty.
Start the lab →Commercial Refrigeration / RAC
~15 min
Walk-in Freezer Defrost Fault
Walk-in freezer keeps icing up. Product temperature climbs a few degrees each day and the customer has been scraping the coil by hand.
Start the lab →Commercial HVAC / RTU
~15 min
Rooftop Unit Not Cooling
Retail space is warm. Thermostat is calling for cooling, the supply fan runs, but the air out of the diffusers is not cold.
Start the lab →