Connecticut Limited Heating Cooling License (D-3 and D-4) Connecticut’s D-3 and D-4 licensing exams span EPA refrigerant regulations, system evacuation and recovery procedures, psychrometric chart interpretation, and heating/cooling equipment installation standards specific to state code. Applicants must grasp pressure-temperature relationships, ductwork design fundamentals, and troubleshooting methodologies for both air-source and ground-source systems to pass confidently.
| Exam Name | Connecticut Limited Heating Cooling License (D-3 and D-4) |
| Format | PDF & Practice Test Engine |
| Target Year | 2026 Updated |
| Features | 100% Verified Q&As |
