R-410A study plan

List the physical properties of R-410A (near-azeotropic blend of R-32 and R-125 at 50/50, higher vapor pressure than R-22, zero ODP, GWP around 2088) and explain why system pressures run roughly 50-70% higher than R-22.

Distinguish saturation temperature, superheat, subcooling, glide, bubble point, and dew point, and compute each from a given pressure-temperature reading.

Identify the safety hazards of R-410A (asphyxiation in low areas, frostbite from liquid contact, oil mist from PVE lubricant) and select the correct PPE for each task.

Explain why R-410A must never be used to retrofit an R-22 system (mineral oil incompatibility, pressure rating of components, POE/PVE lubricant differences).

Recall the cylinder identification, DOT handling, and storage rules for R-410A, including why cylinders are never filled above 80% liquid by volume.

Convert raw gauge readings to saturation temperatures using an R-410A PT chart without errors across 60-120 psig and 200-450 psig ranges.

Explain leak detection methods (electronic, ultrasonic, UV dye, nitrogen pressure test) and state when each is appropriate for R-410A.

Summarize the obligations of Section 608 of the Clean Air Act: technician certification, refrigerant handling prohibitions, and the ban on venting.

State the current leak-rate thresholds, required repair timelines, and documentation requirements for comfort-cooling and commercial refrigeration equipment under EPA leak-repair rules.

Describe recordkeeping duties for refrigerant purchases, disposals, and appliance servicing, and identify who must retain them and for how long.

Differentiate ODP and GWP for R-22, R-410A, R-32, R-454B, and R-134a, and explain how each metric drives regulation.

Trace the HFC phasedown schedule (AIM Act baseline plus allowance reductions) and predict how it affects equipment selection and refrigerant availability.

Apply refrigerant handling, selling, and safe-disposal rules to six real-world scenarios, including buying refrigerant without certification and disposing of recovered refrigerant.

Explain the venting prohibition exceptions and the requirements for recovery equipment certification and self-contained recovery device ratings.

Describe technician certification types (Type I, II, III, Universal) and map each to the equipment it authorizes servicing.

Draw and label the four main components of the vapor-compression cycle and trace refrigerant state (pressure, temperature, phase) at each point.

Explain the function of the compressor, condenser, metering device (TXV vs. piston), and evaporator, and predict the system symptom when each fails.

Interpret superheat and subcooling targets and explain how each indicates charge and metering-device performance.

Map the location and function of accessories: filter-drier, accumulator, muffler, reversing valve, crankcase heater, and service valves.

Define compression ratio, evaporator TD, and condenser split, and calculate each from a set of sample readings.

Compare the superheat method and subcooling method of charging and state when each is required (fixed orifice vs. TXV).

Calculate target superheat and target subcooling from indoor wet-bulb, outdoor dry-bulb, and manufacturer tables, then decide whether to add or remove charge.

Diagnose eight common faults (undercharge, overcharge, restricted filter-drier, restricted liquid line, dirty condenser, low airflow, bad TXV, compressor valve failure) from pressure and temperature readings.

Measure and interpret delta-T, static pressure, and airflow, and identify when airflow is the root cause rather than charge.

Explain compressor electrical checks: winding resistance, insulation resistance to ground, capacitor testing, and locked-rotor symptoms.

Size and select line sets for R-410A, applying velocity limits, pressure-drop limits, and oil-return rules for horizontal, vertical, and long runs.

Describe proper brazing practice with nitrogen purge, including why nitrogen flow prevents oxidation and how to set the flow rate.

Explain evacuation to 500 microns, the triple-evacuation alternative, and how to use a micron gauge with the core removed from the Schrader ports.

Identify the causes of non-condensables and moisture in a system and describe how each shows up in pressure, superheat, and sight-glass behavior.

Perform a standing vacuum and decay test and interpret results to decide whether a leak or moisture problem exists.

Operate recovery equipment correctly: select the right machine type for liquid, vapor, or push-pull recovery, and state the required evacuation levels before opening a system.

Differentiate recovery, recycling, and reclamation, and identify which processes require EPA-certified equipment or a certified reclaimer.

Explain cylinder safety during recovery, including why recovery cylinders must never be overfilled and how to weigh refrigerant in and out.

Describe safe handling of recovered refrigerant blends, including why a blended refrigerant must not be fractionated or topped off after a leak.

Summarize the HFC phase-down timeline and how low-GWP alternatives (R-32, R-454B) change installation, charging, and safety practices, including A2L flammability awareness.

Review every missed practice question from Weeks 1-7 and restate the underlying rule in your own words.

Take two full-length timed practice exams and score 85% or higher on each.

Rehearse quick recall on the highest-yield facts: PT conversions, leak-rate thresholds, evacuation levels, superheat/subcooling targets, and recovery requirements.

Identify your two weakest domains from practice-exam analytics and complete 20 targeted questions on each.