Recovery and leak rules: the numbers the exam tests

Small appliances — the 80/90 rule

Under 40 CFR 82.156, recovery from small appliances must reach 90% efficiency when the appliance's compressor is functioning, and 80% when it is not. Older study banks still test a legacy threshold based on charge weight, so know both framings and read the question carefully.

Larger systems — evacuation levels

Larger equipment is judged by how deep a vacuum you pull rather than a percentage recovered. High- and medium-pressure equipment under 200 lb has an evacuation target of 0 psig, and low-pressure systems use a much deeper target measured in millimetres of mercury. Your equipment class and the system's charge determine which applies.

Cylinder and handling rules

• Never fill a recovery cylinder above its rated capacity — use the 80% rule of thumb for liquid refrigerants unless the cylinder marking says otherwise
• Cylinders must be DOT-approved, labelled and never over-pressurised or heated with an open flame
• Recovered refrigerant must not be vented; it is either recycled, reclaimed, or destroyed by an approved facility
• Refrigerant sold to technicians must come from an EPA-certified recovery/recycling source

Leak rules in practice

Leak repair obligations depend on appliance class, charge size and the refrigerant's global-warming potential. The exam tests the thresholds and the record-keeping duty; the day job tests whether you can find the leak before the third visit. Learn the rule categories rather than memorising a single number — the questions change the appliance class on purpose.