Frozen Coil / Airflow Restriction
- Interactive decision labs
- Built by working technicians
- Path-based verifiable certificate
- Exam preparation only
- Worldwide online
Residential HVAC Service & Diagnostics
~13 min
intermediate
The call
Homeowner says the system runs all day but barely cools, and the vents feel weak and cold-damp rather than cold and strong.
- Equipment
- 2.5-ton R-410A split system, upflow air handler in a hall closet, TXV metering, 7 years old
- Ambient
- 91°F
- Site notes
- Thermostat is calling COOL, set 73°F, space is 80°F. Outdoor unit is running. Supply air is cool but airflow at the registers is noticeably weak. Suction line at the air handler is sweating heavily and cold to the wrist.
Decision 1 of 5
The system is running, the outdoor unit is turning, but the air coming out of the registers is weak.
What is your first action?
Where this lab sits
This is one module lab from Residential HVAC Service & Diagnostics. The full path adds sealed systems, defrost, rack-system orientation and natural-refrigerant safety, each ending in a lab like this one.
Open the full pathNext lab: Residential No-Cool — Split System Not CoolingNext lab: Residential No-Heat — Gas Furnace Short Cycling on IgnitionNext lab: Superheat / Subcooling DecisionNext lab: Walk-in Cooler Not Holding TemperatureNext lab: Ice Machine Not Making IceNext lab: Reach-in / Prep Table Not Holding TemperatureNext lab: Walk-in Freezer Defrost FaultNext lab: Natural Refrigerant Safe-Handling DecisionNext lab: Rooftop Unit Not CoolingNext lab: RTU Economizer Stuck — No Free CoolingNext lab: RTU High Static — Low Airflow and Poor CoolingNext lab: RTU Gas Heat — No Heat / Ignition Fault