NATE Low-GWP study plan
NATE Low-GWP · Give each week a clear focus.
8 weeks · About 6 hours per week
Low GWP Refrigerant (LGWP)
Define global warming potential (GWP) and distinguish it from ozone depletion potential (ODP), stating the reference gas and time horizon used for each
Rank the common low-GWP refrigerants (R-32, R-454B, R-466A, R-1234yf, R-1234ze, R-744, R-717) by GWP and by ASHRAE 34 safety class
Explain the Kigali Amendment phase-down schedule and how the A2L subclass was created to enable flammable-but-lower-risk refrigerants
Identify the three flammability criteria (lower flammability limit, heat of combustion, burning velocity) that separate A2L from A3
Your checkpoint
A one-page handwritten or typed reference table listing at least eight low-GWP refrigerants with GWP, safety class, and typical application, scored against an answer key you build from the standards
Low GWP Refrigerant (LGWP)
Interpret ASHRAE 15 and ASHRAE 15.2 requirements for refrigerant concentration limit (RCL), occupied space, and institutional occupancy
Calculate the allowable charge for a given room volume using RCL and compare it to the nameplate charge
Describe how A2L refrigerants change ventilation, leak detection, and signage requirements versus A1
Explain the role of the refrigerant detection system in mitigating ignition risk
Your checkpoint
Three worked charge-limit calculations for a residential, a commercial, and an institutional space, each with the RCL source cited and a pass/fail conclusion
Low GWP Refrigerant (LGWP)
List the required service-tool changes for A2L systems: recovery machine, vacuum pump, manifold, hoses, and leak detector ratings
Explain why standard A1 leak detectors and recovery cylinders may not be acceptable for A2L
Describe safe handling and cylinder storage practices for flammable refrigerants, including transport classification
Identify personal protective equipment and ignition-source controls needed during brazing and recovery
Your checkpoint
A service-van readiness checklist of at least 15 line items covering tools, PPE, signage, and cylinder storage, each item marked compliant or needs-purchase
Low GWP Refrigerant (LGWP)
Trace the charge, recovery, evacuation, and recharge sequence for an A2L system from start to finish
Explain the effect of glide on charging method for zeotropic blends such as R-454B and R-466A
Describe how to charge a system in liquid phase and why vapor charging is prohibited for blends
Identify the leak-check and pressure-test procedures that differ for flammable refrigerants
Your checkpoint
A written step-by-step commissioning procedure for one A2L residential system, with glide, liquid charging, and leak-check notes, reviewed against manufacturer literature
Low GWP Refrigerant (LGWP)
Compare retrofit versus replacement decisions when moving from R-410A to a low-GWP alternative
Explain oil compatibility and miscibility issues when changing refrigerant families
Describe the impact of low-GWP refrigerants on compressor discharge temperature, capacity, and pressure ratios
Identify which components (expansion device, controls, sensors) typically require change during a low-GWP conversion
Your checkpoint
A decision matrix comparing retrofit and replace options for two scenarios, with at least four technical criteria and a justified recommendation for each
Low GWP Refrigerant (LGWP)
Explain the regulatory drivers: EPA Significant New Alternatives Policy (SNAP), the AIM Act, and HFC allowance allocation
Describe refrigerant reclamation, cylinder tracking, and recordkeeping obligations under current rules
Identify technician certification and training requirements tied to handling flammable refrigerants
Summarize how leak-rate reporting and refrigerant management plans apply to commercial equipment
Your checkpoint
A one-page compliance summary mapping five regulatory requirements to the specific on-site action each demands, with the rule citation for each
Low GWP Refrigerant (LGWP)
Diagnose common A2L system faults: sensor faults, charge imbalance, and ignition-source proximity issues
Apply a systematic troubleshooting sequence that separates refrigerant-side from air-side and electrical faults
Interpret superheat, subcooling, and glide-adjusted saturation readings on a zeotropic system
Explain how leak detection system alarms should be verified and reset
Your checkpoint
Five fault scenarios written out with symptom, likely cause, diagnostic test, and corrective action, each checked against a manufacturer troubleshooting guide
Low GWP Refrigerant (LGWP)
Review all prior deliverables and close gaps flagged in earlier self-checks
Rehearse explaining GWP, safety class, charge limits, and service procedures aloud without notes
Complete a timed practice set of at least 50 questions spanning the full domain
Identify the two weakest subtopics and write a targeted remediation plan for after the exam date
Your checkpoint
A timed practice exam score of at least 80 percent plus a written remediation plan naming the two weakest subtopics and the specific study action for each
Milestones
Week 2: Can state the GWP and safety class of eight low-GWP refrigerants from memory and complete an RCL charge calculation without reference
Week 4: Service-van checklist complete and commissioning procedure written; can list the tool changes required for A2L without notes
Week 6: Can explain the Kigali/AIM Act phase-down and name three recordkeeping obligations without reference
Week 8: Score at least 80 percent on a 50-question timed practice set and have a written remediation plan for the two weakest subtopics