Safety, Tools, and Code Compliance
Safety is not a separate topic - it is threaded through every task. Know personal protective equipment for the job, lockout/tagout, and the hazards specific to HVAC: refrigerant frostbite and asphyxiation in low spaces, carbon monoxide, electrical shock, and fall hazards. Understand refrigerant safety groups (A1 being lower toxicity and no flame propagation) and that recovery cylinders must never be overfilled. Know EPA Section 608 rules: certification required to handle refrigerant, no venting, leak repair requirements, and recordkeeping.
Tools: manifold gauges, micron gauge, vacuum pump, leak detectors, combustion analyzer, manometer, anemometer, clamp meter, and multimeter. Know what each measures and its common misuse - for example, using a manifold gauge to judge vacuum instead of a micron gauge. Code compliance generally means following the mechanical code, manufacturer instructions, and local amendments. In Alaska, state and local codes plus cold-climate requirements govern venting, combustion air, and freeze protection.
Traps: assuming a vacuum pump alone tells you the system is dry (use a micron gauge and a decay test); venting refrigerant; and working alone in a confined space without monitoring.
Worked example: after pulling a vacuum, isolate the pump and watch the micron gauge. A rise that stabilizes below 500 microns suggests a dry system; a continuous rise toward atmosphere suggests a leak or moisture. Document the reading - it is both a quality check and a compliance record.