Moving to District of Columbia as a journeyman HVAC technician: every state's rule

The District of Columbia licenses HVAC technicians as Refrigeration and Air Conditioning Mechanics through the Board of Industrial Trades in the Department of Licensing and Consumer Protection (DLCP), the same board that licenses electricians and plumbers. Three person-held credentials exist: apprentice (registered without exam), Journeyman Refrigeration and Air Conditioning Mechanic, and Master Refrigeration and Air Conditioning Mechanic (regular, or limited to systems of 25 compressor horsepower and below). 17 DCMR § 303.6 requires a journeyman license for anyone doing the mechanical work of installing, maintaining, repairing or replacing refrigeration and air conditioning equipment. DLCP's application instructions require 3 years of experience verified by a master, tax records, a CFC (EPA 608) Universal certification, and a PSI-administered open-book journeyman exam; a graduate of a registered apprenticeship program (classroom work plus 8,000 hours over 4 years under a master) may waive the journeyman exam, which mirrors the national-certification substitute in D.C. Code § 47-2853.202(d). Fees are a $65 application fee and a $110 mechanic license fee; all refrigeration licenses expire September 30 of even-numbered years. The Board publishes reciprocity for electricians and plumbers from Maryland and Virginia but none for refrigeration and air conditioning mechanics.