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High- and very-high-pressure appliances
Type II focuses on high- and very-high-pressure appliances other than small appliances and MVACs. This 25-question mode trains the sequence decisions that matter: identify the system, recover liquid efficiently, reach the correct evacuation level, and service it safely.
Type II questions frequently combine more than one fact. The required evacuation level can depend on appliance pressure category, the system's full charge, and whether the recovery equipment was manufactured before or on/after November 15, 1993. Recovery and charging questions also test where liquid and vapor are found within the refrigeration circuit.
Oil traces, excessive superheat, testing before charging, and choosing nitrogen safely.
Recover liquid first, then vapor; use temperature differences and short, large-diameter hoses to improve speed.
Pressure category, full charge below or at least 200 pounds, equipment date, leak condition, and repair type.
Liquid versus vapor charging, avoiding compressor slugging, noncondensables, and never energizing a hermetic compressor in a vacuum.
| Step | Question to ask | Why it matters |
|---|---|---|
| 1. Classify | Is this high-, very-high-, medium-, or low-pressure equipment? | Pressure category selects the correct rule row. |
| 2. Size the charge | Is the full charge below 200 pounds or 200 pounds and above? | Several high- and medium-pressure evacuation targets split at 200 pounds. |
| 3. Check equipment date | Was the recovery machine made before or on/after November 15, 1993? | Modern equipment can have a deeper required vacuum. |
| 4. Check the service condition | Is the repair major, non-major, or limited by a leak? | Specific exceptions may change what must be achieved before opening. |
Use the recovery and evacuation levels reference to compare the exact current table.
Why is liquid refrigerant normally recovered before the remaining vapor from a high-pressure appliance?
A is correct. Moving the bulk liquid first speeds recovery. Vapor must still be recovered afterward to reach the required level.
A high-pressure appliance has a full charge below 200 pounds. What evacuation level does EPA's table list with either pre-1993 or post-1993 recovery equipment?
A is correct. The high-pressure, under-200-pound row is 0 inches Hg vacuum for both equipment-date columns. Do not borrow the medium-pressure value.
Which gas is the best general choice for pressurizing a system during leak testing?
C is correct. Nitrogen should be used with a regulator and relief valve. Oxygen or compressed air can react dangerously with refrigerant oil under pressure.
After the target vacuum is reached, system pressure rises during a short wait. What is the likely lesson?
B is correct. A pressure rebound can show that refrigerant remains in the system or oil and is continuing to vaporize. Recovery should continue as appropriate.
The same charge size can produce a different target in a different pressure category.
Liquid-first is a speed technique, not permission to leave vapor behind.
Read whether the question says less than 200 or 200 pounds and above.
A compressor motor can be damaged because it is not being cooled normally and electrical arcing risk increases.
Take 25 Type II questions, then use Review Missed to isolate evacuation, recovery, leak, or charging weaknesses.
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