Type II - High-Pressure Appliances
What this domain covers
Type II covers high-pressure equipment that is not a small appliance or a low-pressure chiller: residential split systems, packaged and rooftop units, and high-pressure chillers. The refrigerants are the familiar ones - R-22, R-410A, R-407C, R-134a, R-12, R-500, R-502 - all of which boil well below ambient at atmospheric pressure, so a leak pushes refrigerant out rather than pulling air in.
Rules you must be able to state
- Recovery targets depend on size and age. For an appliance manufactured before November 15, 1993 with less than 200 lb of charge, recover 90% when the compressor is operating and 80% when it is not. Larger appliances and appliances built after that date must be evacuated to a 10 in. Hg vacuum with the compressor running.
- Recovery equipment must be certified to the AHRI 740 standard and rated for the refrigerant being handled.
- Never mix refrigerants in a recovery cylinder. A mixed cylinder cannot be reclaimed and is treated as hazardous waste.
- Blends (400-series) are zeotropic and must be charged as a liquid - into the liquid line or through a throttling device - so the components do not fractionate.
- Pressure testing uses dry nitrogen only. Oxygen or compressed air plus oil can detonate.
Traps that show up in questions
- Quoting the low-pressure vacuum target (25 mm Hg absolute) for a high-pressure job, or the reverse.
- Using R-22 manifold gauges and hoses on R-410A, which runs roughly 50–70% higher pressure and needs its own equipment.
- Vapor-charging a blend, or heating a cylinder with a torch to speed the transfer.
Rule of thumb
When the data plate and the recovery table disagree about how far to pull down, match the appliance's manufacture date and charge size first, then apply the 90%/80% or 10 in. Hg figure.