EPA 608 Type II Study Guide

What Type II Covers

A high-pressure appliance uses a refrigerant with a liquid-phase saturation pressure between 170 and 355 psia at 104 °F, such as R-22, R-410A, R-404A and R-454B. A medium-pressure appliance uses a refrigerant between 45 and 170 psia at 104 °F, such as R-134a and R-114. Very high-pressure refrigerants (above 355 psia) such as R-13 and R-503 also fall under Type II. Definitions are in 82.152.

Type II excludes small appliances (Type I) and motor vehicle air conditioning (Section 609). Typical Type II equipment: residential and light-commercial split systems, packaged rooftop units, walk-in coolers, reach-in cases and supermarket racks.

Evacuation Levels (Table 1)

Before opening a Type II appliance for maintenance, service, repair or disposal, the technician must evacuate it to the level in Table 1 of 82.156, using certified recovery equipment:

Check the live eCFR table before your exam. The figures above are summarised from 82.156(a); our EPA 608 Recovery and Evacuation Requirements page reproduces the full table, including low-pressure levels.

Major vs Non-Major Repairs

A major repair involves removing the compressor, condenser, evaporator or an auxiliary heat-exchange coil, or uncovering an opening of more than 4 square inches of flow area for more than 15 minutes. If a repair is not major and isn’t followed by evacuation to the environment, the appliance only needs to be brought to 0 psig before opening.

If the system leaks so badly that the vacuum can’t be reached, evacuate non-leaking parts to Table 1 levels and the leaking part to the lowest level possible without contaminating the refrigerant, and never above 0 psig.

Leak Detection

Leak detection is a large share of Type II. Know these methods:

• Overall checks come first: oil residue, hissing, frost spots and a soap-bubble test on suspect joints.
• Electronic leak detectors (heated diode, infrared or corona) find small leaks; move the probe slowly below the suspected leak, since most refrigerants are heavier than air.
• Ultrasonic detectors listen for the sound of escaping gas.
• Fluorescent dye with a UV light shows leaks where approved by the system manufacturer.
• Standing pressure test: after repair, pressurise with dry nitrogen (never oxygen or compressed air), using a regulator and relief valve, and watch for a pressure drop.

A trace amount of the system refrigerant may be used with nitrogen as a tracer gas; this is not considered venting when used for leak detection.

Signs of a leak on a running system include low suction pressure, a starved evaporator, high superheat and oil stains.

Leak Repair Triggers

For appliances with 50 lb or more of a CFC or HCFC (or a blend containing one), 82.157 requires repair when the annual leak rate exceeds:

• 20% for commercial refrigeration
• 30% for industrial process refrigeration
• 10% for comfort cooling and other appliances

Leaks must be repaired within 30 days, then verified with an initial and follow-up verification test. The full detail, including inspections and chronic-leaker reports, is in EPA 608 Leak Repair Rules.

Recovery Techniques

• Recover liquid first. Liquid moves much faster than vapour. Pull liquid from the liquid line or receiver, then switch to vapour recovery.
• Push-pull method moves large amounts of liquid by pulling vapour from the recovery cylinder and pushing it into the system to drive liquid out. It works best on larger systems with an accessible liquid line, and needs care on heat pumps where a reversing valve can trap refrigerant.
• Chill the recovery cylinder to lower its pressure and speed things up.
• Recover from both sides (high and low) where possible.
• After recovery, wait a few minutes. If pressure rises, refrigerant was trapped in oil or a cold spot; recover again.
• Recovered refrigerant can be returned to the same system or another system owned by the same person without reclaiming. See Recover vs Recycle vs Reclaim Refrigerant.

System Basics You Need

Expect questions that test whether you understand the refrigeration cycle:

• The compressor raises pressure and temperature of vapour; the condenser rejects heat and turns vapour to liquid; the metering device drops pressure; the evaporator absorbs heat.
• The receiver stores liquid; the accumulator protects the compressor from liquid slugging.
• A system with a receiver should have its liquid recovered from the receiver outlet.
• Moisture causes acid and ice at the metering device; that’s why a deep dehydration evacuation is needed before charging.

Safety Points for Type II

• High-pressure refrigerants such as R-410A operate at much higher pressures than R-22; use rated gauges and hoses.
• Many newer systems use A2L refrigerants such as R-454B and R-32. Follow manufacturer procedures and use recovery equipment rated for them. See Refrigerant Types, Classes and A2L Safety.
• Never heat a cylinder with an open flame.

Practise and Review

Work through the table and trigger percentages until you can write them from memory, then take the EPA 608 Type II practice test. Its explanations cite the paragraph each answer comes from.

Common Exam Traps

• The 200 lb line. Evacuation levels change at 200 lb charge; leak repair starts at 50 lb. Don’t mix them up.
• 0 psig vs vacuum. 0 psig applies only to non-major repairs not followed by evacuation.
• Nitrogen, not oxygen. Any answer involving oxygen or compressed air for pressure testing is wrong.
• Leak rules and HFCs. 82.157 covers ODS appliances; HFC rules sit in Part 84.

Five Facts Worth Memorising

1. High-pressure appliances under 200 lb with post-1993 equipment: 0 in. Hg.
2. Medium-pressure appliances of 200 lb or more with post-1993 equipment: 15 in. Hg.
3. Comfort cooling leak repair trigger: 10% for 50 lb or more of a CFC or HCFC.
4. Leak repairs are due within 30 days, followed by initial and follow-up verification tests.
5. Recovering liquid first speeds up the job on larger systems.