7.7 - Self-Contained Recovery

Module: Type I Small Appliances
Regulatory and source verification date: August 11, 2026
Primary verification basis: Current 40 CFR Part 82, Subpart F; current U.S. EPA Section 608 recovery-equipment and test-topic guidance; current recovery-equipment manufacturer instructions used only for equipment-specific connection examples
Course role: Explains Type I recovery when an independent recovery machine supplies the refrigerant-moving force, including the recovery-machine compressor, pressurized recovery cylinder, correct cylinder connection, noncondensables, cylinder cooling, recovery-machine discharge pressure, and prevention of refrigerant cross-contamination

Learning Objectives

After completing this section, a student should be able to:

1. Define self-contained recovery equipment using the current federal definition.

2. Explain how self-contained recovery differs from system-dependent recovery.

3. Identify the independent recovery-machine compressor as the refrigerant-moving device in a typical self-contained recovery machine.

4. Explain why the appliance compressor does not have to operate during self-contained recovery.

5. Describe the basic refrigerant path:

   Appliance
   → recovery machine
   → recovery cylinder
   

6. Explain why a self-contained recovery machine normally discharges into an approved pressurized recovery cylinder, rather than the nonpressurized container discussed in Section 7.6.

7. Explain how to determine the correct recovery-cylinder port from the recovery-machine manufacturer’s instructions.

8. Recognize the common direct-recovery arrangement in which the recovery-machine outlet connects to the cylinder liquid port, while avoiding an unsupported rule that every machine must use the same port.

9. Explain how refrigerant vapor pressure, cylinder temperature, and noncondensable gases affect recovery-cylinder pressure.

10. Explain how a pressure-temperature comparison can help identify possible noncondensables in a stabilized recovery cylinder.

11. Explain why cooling a recovery cylinder can reduce cylinder pressure and improve recovery speed.

12. Identify safe and unsafe methods of cylinder cooling.

13. Explain why high recovery-machine discharge pressure slows recovery and can cause the machine to shut down on high pressure.

14. Identify common causes of excessive recovery-machine discharge pressure.

15. Explain how to reduce cross-contamination when changing from one refrigerant to another.

16. Explain why refrigerants should not be intentionally mixed in a recovery cylinder.

17. Apply the current Type I recovery endpoint while using self-contained equipment.

18. Apply the complete self-contained-recovery process to EPA 608 examination scenarios.

Introduction

Sections 7.5 and 7.6 focused on system-dependent recovery.

In system-dependent recovery, refrigerant removal depends on assistance from the appliance or conditions within it.

Examples include:

Operating appliance compressor

Refrigerant pressure

Controlled heat

and, in the special failed-compressor Type I example:

vacuum-pump assistance
+
nonpressurized recovery container

Self-contained recovery is fundamentally different.

Current 40 CFR §82.152 defines self-contained recovery equipment as recovery and/or recycling equipment capable of removing refrigerant from an appliance:

WITHOUT assistance from components contained in the appliance

A typical portable self-contained recovery machine contains its own compressor or other independent refrigerant-moving mechanism.

The basic concept is:

APPLIANCE
↓
recovery-machine INLET
↓
INDEPENDENT RECOVERY COMPRESSOR
↓
recovery-machine OUTLET
↓
PRESSURIZED RECOVERY CYLINDER

The appliance compressor may be:

• Operating.
• Inoperative.
• Electrically disconnected.
• Mechanically failed.

The recovery machine can still provide the refrigerant-moving force if it is appropriate for the refrigerant and appliance.

This makes self-contained recovery particularly useful when:

• The appliance compressor has failed.
• Faster recovery is desired.
• System pressure alone is not sufficient.
• A recovery procedure should not depend on appliance operation.

The recovery machine does not eliminate the need to:

• Identify the refrigerant.
• Use the correct recovery cylinder.
• Control cylinder fill.
• Avoid mixing refrigerants.
• Monitor pressures.
• Reach the applicable Section 7.3 recovery endpoint.
• Follow manufacturer instructions.

Key Concepts

1. Current Federal Definition

Current 40 CFR §82.152 defines:

Self-contained recovery equipment

as refrigerant recovery and/or recycling equipment capable of removing refrigerant from an appliance without assistance from components contained in the appliance.

The key examination distinction is:

Requires appliance assistance
→ system-dependent recovery equipment

Does NOT require appliance assistance
→ self-contained recovery equipment

2. Independent Recovery Compressor

Many portable self-contained recovery machines contain their own compressor.

That recovery-machine compressor:

1. Draws refrigerant from the appliance.
2. Compresses the refrigerant.
3. Raises pressure enough to move refrigerant through the discharge hose.
4. Forces refrigerant into the recovery cylinder.

Therefore:

recovery-machine compressor
→ provides recovery force

This is different from:

appliance compressor
→ provides recovery force

which describes the operating-compressor system-dependent method taught in Section 7.5.

3. Appliance Compressor Condition Is Not Required for the Equipment Definition

A self-contained recovery machine can recover refrigerant without relying on the appliance compressor.

Therefore:

appliance compressor works
or
appliance compressor fails
↓
self-contained machine can still provide independent recovery force

This does not mean appliance condition is irrelevant to all service decisions.

Compressor condition can still affect:

• Refrigerant distribution.
• Access-point selection.
• Recovery speed.
• Applicable small-appliance percentage requirement.

But the self-contained recovery machine itself does not require the appliance compressor to perform the pumping work.

4. Basic Self-Contained Recovery Flow

The simplest conceptual arrangement is:

Appliance
→ recovery-machine inlet
→ recovery-machine compressor
→ recovery-machine outlet
→ pressurized recovery cylinder

If a manifold is used:

Appliance high / low access
→ manifold
→ center/service hose
→ recovery-machine inlet
→ recovery-machine outlet
→ recovery cylinder

The exact hose arrangement depends on:

• Appliance access.
• Recovery-machine design.
• Refrigerant.
• Whether liquid or vapor recovery is being performed.
• Manufacturer instructions.

Do not memorize one plumbing arrangement as universal for every recovery machine.

Independent Recovery Compressor

1. What the Recovery Compressor Does

A portable recovery machine must overcome the pressure difference between:

appliance

and:

recovery cylinder

As recovery proceeds, the appliance pressure normally decreases while the recovery-cylinder pressure can increase.

The recovery-machine compressor provides the pressure rise required to keep refrigerant moving.

Conceptually:

lower-pressure refrigerant at machine inlet
→ compressor
→ higher-pressure refrigerant at machine outlet
→ recovery cylinder

2. Recovery Machine Is Not the Appliance Compressor

A common exam error is to confuse the two compressors.

3. Machine Compressor Must Be Protected

A recovery machine can be damaged by:

• Excessive liquid slugging.
• Excessive discharge pressure.
• Wrong refrigerant.
• Flammable refrigerant when the machine is not approved for it.
• Debris.
• Acid or contaminated refrigerant.
• Operating against a closed valve.
• Poor ventilation around the machine.

Follow the recovery-machine manufacturer instructions for:

• Liquid versus vapor recovery.
• Valve positions.
• Throttling.
• Filters.
• Purging or clearing the machine.
• Refrigerant changeover.
• Shutdown.

Pressurized Recovery Cylinder

1. Self-Contained Recovery Commonly Uses a Recovery Cylinder

The refrigerant leaving a self-contained recovery machine must be stored in an external container.

A typical field arrangement uses an approved reusable recovery cylinder designed for refrigerant recovery.

The recovery cylinder is different from:

• A disposable refrigerant cylinder.
• An open container.
• The nonpressurized container used in the special passive-recovery example in Section 7.6.

The basic relationship is:

recovery machine
→ pressurized recovery cylinder

2. Never Use a Disposable Cylinder as a Recovery Cylinder

A disposable cylinder is intended for one-way product distribution.

Do not refill it with recovered refrigerant.

EPA test topics specifically distinguish:

• Reusable recovery cylinders.
• Disposable cylinders.

Recovered refrigerant belongs in an appropriate reusable recovery container.

3. Do Not Overfill the Recovery Cylinder

The course previously established the commonly taught recovery-cylinder fill limit:

Do not fill more than 80% full

The purpose is to leave vapor space for thermal expansion.

Cylinder fill should be controlled by weight, not by guessing from pressure alone.

For a cylinder with known water capacity:

maximum refrigerant mass

depends on the cylinder’s rated capacity, refrigerant density, cylinder specifications, and applicable manufacturer/DOT requirements.

Use the cylinder and recovery-equipment instructions rather than assuming one universal refrigerant mass.

Correct Recovery-Cylinder Port

1. Recovery Cylinders May Have Separate Liquid and Vapor Ports

Many reusable recovery cylinders have two service valves:

LIQUID

and:

VAPOR

Internally, the liquid valve commonly connects to a dip tube extending toward the bottom of the cylinder.

The vapor valve normally communicates with the vapor space near the top.

This distinction matters when connecting recovery equipment.

2. Follow the Recovery-Machine Manufacturer Instructions

There is not one universally correct cylinder port for every possible recovery machine and recovery technique.

The controlling rule is:

Connect the recovery-machine outlet to the cylinder port specified by the recovery-machine manufacturer for the selected recovery method.

This avoids turning a manufacturer-specific arrangement into an incorrect universal EPA rule.

3. Common Direct-Recovery Arrangement: Machine Outlet to Liquid Port

A common modern recovery-machine configuration connects:

recovery-machine OUTLET
→ recovery-cylinder LIQUID port

For example, current Appion G5Twin operating instructions specify the recovery-machine output to the Liquid Port on the Recovery Cylinder for conventional direct-recovery procedures.

This arrangement lets refrigerant enter through the cylinder’s liquid-side dip tube.

However:

common arrangement
≠ universal requirement

Another approved procedure may intentionally use a different cylinder port or cylinder orientation.

4. Cylinder Vapor Port May Be Used in Specialized Procedures

Certain manufacturer procedures may use the cylinder vapor port for:

• Push-pull recovery.
• Cylinder cooling.
• Specialized high-speed recovery arrangements.
• Other manufacturer-defined configurations.

Therefore, an exam or field question that provides a specific equipment procedure should follow that procedure.

5. Do Not Choose the Port From Hose Color Alone

The recovery-machine discharge hose may be:

• Yellow.
• Red.
• Another manufacturer-selected color.

Hose color does not define the cylinder port.

Use:

machine outlet identification
+
cylinder valve identification
+
manufacturer instructions

to determine the correct connection.

Liquid Port Versus Vapor Port

Important Exam Principle

Do not answer:

Always use liquid port

unless the question gives the machine/procedure for which that is specified.

Do not answer:

Always use vapor port

either.

The safe generalized rule is:

follow recovery-machine manufacturer's specified cylinder connection

Noncondensables

1. What Are Noncondensables?

Noncondensables are gases that do not condense under the refrigerant’s normal condensing conditions inside the recovery cylinder.

The most common contaminant is:

air

Air can enter:

• An appliance that has operated below atmospheric pressure.
• Open hoses or recovery equipment.
• A cylinder that was not properly prepared.
• A system during improper service.
• Recovery equipment during careless connection or refrigerant changeover.

2. Why Noncondensables Matter

Noncondensables can cause:

• Higher cylinder pressure.
• Higher recovery-machine discharge pressure.
• Slower recovery.
• High-pressure cutout.
• Contamination of recovered refrigerant.
• Incorrect refrigerant pressure-temperature behavior.

3. EPA Type I Exam Topic

Current EPA Type I test topics specifically include:

Use of pressure and temperature to identify refrigerants and detect noncondensables.

Therefore, students should understand the underlying pressure-temperature logic.

Detecting Possible Noncondensables by Pressure and Temperature

1. Pure Refrigerant Has a Saturation Pressure at a Given Temperature

For a known pure refrigerant in a cylinder containing both liquid and vapor, the refrigerant pressure should correspond approximately to the saturation pressure at the refrigerant temperature after the cylinder has stabilized.

Conceptually:

known refrigerant
+
known cylinder temperature
→ expected saturation pressure

2. Pressure Too High Can Suggest Noncondensables

If the cylinder:

• Contains a known refrigerant.
• Has been allowed to stabilize.
• Contains liquid refrigerant.
• Has an accurate temperature measurement.
• Shows a pressure significantly above the expected saturation pressure,

then the excess pressure can indicate the presence of noncondensable gas.

Conceptually:

measured pressure
>
expected saturation pressure
→ possible noncondensables

3. Pressure-Temperature Comparison Is Not a Stand-Alone Purity Test

An abnormal pressure can also result from:

• Wrong refrigerant identification.
• Refrigerant mixture.
• Zeotropic blend behavior.
• Cylinder temperature not actually stabilized.
• Measurement error.
• Refrigerant contamination.
• Overfilled cylinder.

Therefore:

P-T mismatch
→ diagnostic clue

not:

P-T mismatch
→ automatic proof of air

4. Do Not Vent a Recovery Cylinder to “Purge Air”

Do not intentionally vent refrigerant merely because noncondensables are suspected.

Recovered contaminated refrigerant should be handled according to the appropriate reclamation, recovery, or disposal pathway.

Cylinder Cooling

1. Why Cylinder Cooling Helps Recovery

The recovery machine must discharge against the pressure in the recovery cylinder.

As refrigerant enters the cylinder:

• Refrigerant condenses.
• Heat is released.
• Cylinder temperature can rise.
• Cylinder saturation pressure increases.

Therefore:

hotter recovery cylinder
→ higher cylinder pressure
→ higher machine discharge pressure
→ slower recovery

Cooling the cylinder can reverse this trend:

cooler cylinder
→ lower refrigerant saturation pressure
→ lower recovery-machine discharge pressure
→ larger pressure difference
→ faster recovery

2. Cylinder Cooling Is a Recovery-Speed Technique

EPA test topics identify chilling the recovery vessel as a method that can speed refrigerant recovery.

The physics apply to self-contained recovery as well:

lower destination pressure
→ easier refrigerant transfer

3. Safe Cooling Methods

Depending on cylinder and equipment instructions, safe methods can include:

• Airflow over the cylinder.
• Placement in a container of cool water while protecting valves and equipment as required.
• Manufacturer-approved refrigerant/cylinder-cooling procedures.
• Keeping the cylinder out of direct sun and away from hot surfaces.

Do not use:

• Dry ice unless an explicitly approved procedure calls for it.
• An uncontrolled ice/salt bath.
• A freezer as an improvised field procedure.
• Any cooling method that can damage valves, labels, scales, or cylinder integrity.

4. Cooling Does Not Permit Overfilling

A cold cylinder can accept refrigerant at a lower pressure, but:

lower pressure
≠ more allowable refrigerant mass

The cylinder must still remain within its permitted fill limit.

5. Keep the Cylinder on a Scale

During recovery:

recovery cylinder
→ on an appropriate scale

helps prevent overfill.

Do not use cylinder pressure as the primary fill indicator.

Recovery-Machine Discharge Pressure

1. What Is Discharge Pressure?

The recovery machine takes refrigerant at its inlet and compresses it toward the outlet.

The discharge pressure is the pressure the machine must overcome on its outlet side.

In a basic arrangement:

recovery-machine outlet
→ discharge hose
→ recovery cylinder

Therefore, recovery-machine discharge pressure is strongly influenced by:

• Recovery-cylinder pressure.
• Outlet hose restriction.
• Cylinder valve position.
• Refrigerant.
• Cylinder temperature.

2. High Discharge Pressure Slows Recovery

As discharge pressure rises:

• Recovery-machine compressor load increases.
• Refrigerant mass-flow rate may decrease.
• Machine temperature can rise.
• High-pressure protection may trip.

A useful concept is:

lower discharge pressure
→ easier recovery

3. Common Causes of Excessive Discharge Pressure

Possible causes include:

• Recovery cylinder too warm.
• Recovery cylinder overfilled.
• Cylinder valve closed or partially closed.
• Wrong cylinder port for the selected manufacturer procedure.
• Restrictive or kinked discharge hose.
• Excessively long hose.
• Noncondensables in cylinder.
• Refrigerant with high condensing pressure.
• Blocked filter or fitting.
• Recovery-machine outlet valve improperly positioned.
• Poor airflow around the recovery machine.
• Internal equipment problem.

4. High-Pressure Cutout Is a Safety Device

Many recovery machines contain high-pressure protection.

Do not bypass a high-pressure cutout to continue recovery.

Instead:

machine stops on high pressure
→ identify cause
→ correct safe condition
→ restart according to manufacturer procedure

5. Cooling the Cylinder Can Reduce Discharge Pressure

If high discharge pressure is caused by a hot recovery cylinder:

approved cylinder cooling
→ lower cylinder temperature
→ lower cylinder pressure
→ lower recovery-machine discharge pressure

This is why cylinder cooling and discharge-pressure control are closely related.

Recovery Speed

Recovery speed depends on several interacting factors.

EPA’s Core recovery-technique topics identify factors including:

• Ambient temperature.
• Recovery-equipment size.
• Hose length.
• Hose diameter.

For self-contained Type I recovery, additional practical factors include:

• Refrigerant state entering machine.
• Appliance pressure.
• Cylinder pressure.
• Discharge pressure.
• Restrictions in access fittings.
• Valve cores.
• Hose fittings.
• Recovery-machine condition.
• Refrigerant viscosity and density.
• Oil and trapped refrigerant.

A technician should improve recovery speed through:

larger practical flow path
+
shorter appropriate hoses
+
low cylinder pressure
+
correct valve positions
+
appropriate machine

not by bypassing safety devices or venting refrigerant.

Recovering Liquid Versus Vapor

1. Liquid Recovery Is Usually Faster

A much greater refrigerant mass can pass through a hose as liquid than as low-density vapor.

Therefore, many self-contained recovery procedures begin by removing liquid refrigerant when liquid access is available.

EPA’s Type II test topics explicitly recognize that recovering liquid at the beginning can speed recovery.

The same physical principle applies to recovery-machine operation generally.

2. Small Appliances May Offer Limited Liquid Access

Small appliances often have:

• Process stubs.
• Capillary tubes.
• Limited factory service access.

The field connection may not provide a convenient dedicated receiver-liquid connection.

Therefore, use the recovery method and access arrangement appropriate to the appliance and machine.

3. Protect the Recovery Machine From Liquid Slugging

Some recovery machines are designed to handle substantial liquid flow.

Others require throttling or another manufacturer procedure.

If the recovery machine shows signs of liquid slugging:

• Follow the manufacturer’s throttling procedure.
• Do not intentionally flood a machine contrary to its instructions.
• Do not assume all machines tolerate liquid in the same way.

Avoiding Cross-Contamination

1. Do Not Mix Refrigerants

EPA test topics specifically include:

Need to avoid mixing refrigerants

Recovered refrigerants should be kept separated whenever practical.

Do not knowingly mix:

• R-12 with R-134a.
• R-22 with R-410A.
• R-134a with R-600a.
• Different blends.
• Known refrigerant with unknown refrigerant.

2. Why Mixed Refrigerant Is a Problem

Mixed refrigerant can:

• Be unsuitable for reuse.
• Prevent normal pressure-temperature identification.
• Require special reclamation or destruction handling.
• Contaminate recovery equipment.
• Contaminate other appliances.
• Increase disposal/reclamation cost.

3. Use a Correctly Identified Recovery Cylinder

Before recovery, verify:

• Cylinder is appropriate and reusable.
• Cylinder is within qualification requirements.
• Cylinder is not overfilled.
• Cylinder contents are known.
• Cylinder is assigned to the refrigerant being recovered or to a clearly identified contaminated-refrigerant stream.

Do not use cylinder color alone to identify contents.

Read:

• Cylinder label.
• Refrigerant identification.
• Service documentation.

4. Clear or Prepare Recovery Equipment Between Refrigerants

A recovery machine and hoses can retain refrigerant after a job.

Before switching to another refrigerant:

• Use the manufacturer’s machine-clearing or purge procedure.
• Manage residual refrigerant properly.
• Change filter/drier or other components if required.
• Use dedicated equipment when required or appropriate.
• Verify compatibility with the next refrigerant.

Do not create your own purge-to-atmosphere procedure.

5. Flammable-Refrigerant Cross-Contamination Can Add Safety Risk

Mixing a flammable refrigerant into equipment intended for a nonflammable refrigerant can create:

• Unexpected flammability.
• Equipment incompatibility.
• Ignition risk.
• Incorrect recovery-machine operating conditions.

Use recovery equipment specifically approved for the refrigerant safety class where required.

Self-Contained Recovery and the Type I Recovery Endpoint

Self-contained recovery changes how refrigerant is moved.

It does not change the current small-appliance recovery endpoint.

Before opening or disposing of a small appliance, current 40 CFR §82.156(b) requires:

Pre-Nov. 15, 1993 recovery equipment
→ 80% recovery

or, for recovery equipment manufactured on or after November 15, 1993:

appliance compressor functioning
→ 90%

appliance compressor not functioning
→ 80%

or:

evacuate appliance to 4 in. Hg vacuum

The condition of the appliance compressor remains relevant to the percentage requirement even when a separate self-contained recovery machine performs the recovery work.

This is an important exam distinction.

Example

A small appliance has:

• A failed appliance compressor.
• A self-contained recovery machine manufactured in 2025.

The machine provides its own recovery force.

But the applicable percentage pathway is still:

appliance compressor not functioning
→ 80%

or the applicable:

4 in. Hg vacuum

alternative.

Do not reason:

recovery machine has a working compressor
→ 90%

The regulation asks whether the compressor in the appliance is functioning.

Self-Contained Recovery Setup

A common generic connection is:

SMALL APPLIANCE
↓
approved access fitting(s)
↓
manifold or direct recovery hose
↓
RECOVERY-MACHINE INLET
↓
independent recovery compressor
↓
RECOVERY-MACHINE OUTLET
↓
approved reusable recovery cylinder

If the machine manufacturer specifies the cylinder liquid port:

machine outlet
→ cylinder LIQUID port

Use that connection.

If the manufacturer specifies another arrangement:

follow that approved arrangement

The Section 608 rule requires recovery equipment to be used according to manufacturer directions unless those directions conflict with federal requirements.

Step-by-Step Self-Contained Recovery Procedure

Step 1 - Identify the Appliance

Confirm that it is a Type I small appliance.

Review:

Section 7.1 - Small Appliance Definition and Examples.

Step 2 - Identify the Refrigerant

Use:

• Appliance nameplate.
• Manufacturer information.
• Refrigerant identification procedure if necessary.

Do not connect an unknown refrigerant to a clean recovery cylinder intended for a known refrigerant.

Step 3 - Determine Appliance Compressor Condition

Record whether the appliance compressor is:

functioning

or:

not functioning

This affects the applicable Type I percentage recovery endpoint for post-November 15, 1993 recovery equipment.

Step 4 - Determine the Required Endpoint

Use Section 7.3.

Do not wait until the end of recovery to decide what endpoint applies.

Step 5 - Select the Recovery Machine

Verify that the machine is:

• Appropriate for small-appliance service.
• Properly certified where required.
• Compatible with the refrigerant.
• Suitable for flammable refrigerant if applicable.
• In serviceable condition.

Step 6 - Prepare the Recovery Cylinder

Verify:

• Reusable recovery cylinder.
• Correct cylinder for refrigerant.
• Known contents.
• Adequate available capacity.
• Acceptable cylinder condition.
• Correct labels.
• Weight monitored on a scale.

Step 7 - Identify the Correct Cylinder Port

Read the recovery-machine instructions.

For many direct-recovery machines:

machine OUTLET
→ cylinder LIQUID port

but do not assume this universally.

Step 8 - Prepare the Appliance Access

Use the appropriate:

• Process stub.
• Temporary access fitting.
• High-side and/or low-side connection.

Review Section 7.4.

Step 9 - Connect Appliance to Recovery-Machine Inlet

Depending on the machine:

appliance
→ manifold center/service hose
→ machine inlet

or:

appliance
→ direct recovery hose
→ machine inlet

Step 10 - Connect Machine Outlet to Recovery Cylinder

Use:

machine outlet
→ manufacturer-specified cylinder port

Confirm cylinder valve identification before opening valves.

Step 11 - Check Hose Routing

Before starting:

• Machine inlet goes toward appliance.
• Machine outlet goes toward recovery cylinder.
• Cylinder connection is correct.
• No hose is kinked.
• Required valves are closed/open according to start procedure.
• Cylinder is on the scale.

Step 12 - Start Recovery

Follow the machine’s exact startup procedure.

Do not start the machine against a closed discharge path unless the manufacturer specifically directs such a sequence.

Step 13 - Monitor Inlet and Discharge Conditions

Watch for:

• Appliance pressure.
• Machine inlet pressure.
• Recovery-cylinder pressure.
• Machine discharge pressure.
• Cylinder weight.
• Machine temperature.
• Abnormal sound.

Step 14 - Control Liquid Flow if Required

If liquid refrigerant causes machine knocking or slugging:

• Use the manufacturer-approved throttling procedure.
• Do not continue damaging operation.

Step 15 - Control Cylinder Temperature

If cylinder temperature and pressure rise excessively:

• Improve airflow.
• Move cylinder away from heat.
• Use approved cylinder-cooling technique if appropriate.

Do not exceed cylinder fill limits.

Step 16 - Respond to High Discharge Pressure

If high-pressure protection operates:

STOP
→ identify cause

Check:

• Cylinder pressure.
• Cylinder temperature.
• Cylinder fill.
• Cylinder valve.
• Discharge hose restriction.
• Noncondensables.
• Equipment airflow.

Do not bypass protection.

Step 17 - Continue to the Required Endpoint

Continue recovery until the applicable Section 7.3 endpoint is achieved.

Step 18 - Follow Machine Clearing / Self-Purge Procedure

Many recovery machines retain refrigerant internally.

If the machine has a self-purge or clearing procedure:

• Follow the manufacturer instructions.
• Move retained refrigerant into the appropriate recovery cylinder.
• Do not vent the machine merely to clear it.

Step 19 - Close and Disconnect Using Low-Loss Practices

Use:

• Correct valve sequence.
• Low-loss fittings.
• Hose-refrigerant management procedure.

Step 20 - Remove Temporary Access Fittings as Required

Current EPA Type I test topics state that solderless access fittings should be removed at the conclusion of service.

Reseal and leak check as taught in Section 7.4.

Noncondensables and Recovery-Machine Discharge Pressure

These two topics are closely related.

Suppose a recovery cylinder contains:

refrigerant
+
air

At a given cylinder temperature:

refrigerant vapor
→ contributes refrigerant saturation pressure

while:

air
→ adds partial pressure

The resulting cylinder pressure can be higher than expected for pure refrigerant.

Therefore:

noncondensables
→ higher cylinder pressure
→ higher machine discharge pressure
→ slower recovery / high-pressure trip

This is why a pressure-temperature mismatch can help diagnose a recovery problem.

Cylinder Cooling and Recovery Speed

Consider a self-contained recovery machine operating between:

appliance pressure = decreasing

and:

recovery-cylinder pressure = increasing

The machine’s job becomes more difficult as the pressure ratio increases.

Cylinder cooling helps by reducing the pressure on the discharge side.

Conceptually:

cool cylinder
→ lower cylinder pressure
→ lower machine discharge pressure
→ lower compressor load
→ improved recovery rate

This does not change:

• Cylinder fill limit.
• Refrigerant identity.
• Required EPA recovery endpoint.
• Manufacturer safety requirements.

Cross-Contamination Example

A technician has just recovered R-134a.

The next appliance contains R-600a.

Before connecting the same machine:

Do NOT simply connect and begin recovery.

The technician must determine:

• Is the recovery machine approved for R-600a?
• Is the machine approved for flammable refrigerant?
• What machine-clearing procedure is required?
• Are dedicated hoses or equipment required?
• Is the recovery cylinder dedicated and correctly identified?
• Could residual R-134a contaminate the R-600a cylinder?
• Could residual flammable refrigerant later contaminate equipment intended for nonflammable refrigerant?

The correct principle is:

identify
→ segregate
→ clear equipment correctly
→ use compatible recovery equipment

System-Dependent Versus Self-Contained Type I Recovery

Important Terms

Self-Contained Recovery Equipment

Recovery/recycling equipment capable of removing refrigerant from an appliance without assistance from components contained in the appliance.

Independent Recovery Compressor

The compressor or independent refrigerant-moving mechanism contained in a self-contained recovery machine.

It is separate from the appliance compressor.

Recovery-Machine Inlet

The connection through which refrigerant enters the recovery machine from the appliance.

Recovery-Machine Outlet

The connection through which refrigerant leaves the recovery machine and moves toward the recovery cylinder.

Recovery Cylinder

A reusable container intended to receive recovered refrigerant.

Do not confuse it with a disposable virgin-refrigerant cylinder.

Liquid Port

A recovery-cylinder connection commonly attached to an internal dip tube extending toward the lower portion of the cylinder.

Many direct recovery-machine procedures connect the recovery-machine outlet to this port.

Vapor Port

A recovery-cylinder connection that communicates with the cylinder vapor space.

It may be used for vapor transfer or specialized manufacturer procedures.

Noncondensable

A gas, commonly air, that does not condense with the refrigerant under normal cylinder condensing conditions.

Discharge Pressure

Pressure on the outlet side of the recovery machine.

High discharge pressure increases machine load and can slow or stop recovery.

Cross-Contamination

Unwanted mixing of different refrigerants or contamination of a refrigerant by residual material from recovery equipment, hoses, cylinders, or another system.

EPA 608 Exam Focus

Exam Rule 1 - Identify the Recovery Equipment Category

If the equipment can remove refrigerant without assistance from appliance components:

SELF-CONTAINED

If it requires appliance assistance:

SYSTEM-DEPENDENT

Exam Rule 2 - Do Not Confuse the Two Compressors

Appliance compressor
≠
recovery-machine compressor

A self-contained recovery machine uses its own independent refrigerant-moving capability.

Exam Rule 3 - Appliance Compressor Condition Still Controls the Type I Percentage

For post-November 15, 1993 recovery equipment:

appliance compressor functioning
→ 90%

appliance compressor not functioning
→ 80%

The fact that the recovery machine has a functioning compressor does not make the appliance-compressor condition “functional.”

Exam Rule 4 - Use a Reusable Recovery Cylinder

Do not recover into:

disposable refrigerant cylinder

Use an appropriate reusable recovery cylinder.

Exam Rule 5 - Know the Correct Cylinder Port Concept

The best general answer is:

Connect recovery-machine outlet
→ cylinder port specified by machine manufacturer

For many conventional direct-recovery machines:

machine outlet
→ LIQUID port

But do not turn that common arrangement into a universal rule when equipment instructions specify otherwise.

Exam Rule 6 - Noncondensables Raise Pressure

For a stabilized cylinder of known refrigerant:

pressure significantly higher than expected P-T value
→ possible noncondensables

Exam Rule 7 - Cooling the Cylinder Can Speed Recovery

cooler recovery cylinder
→ lower cylinder pressure
→ lower machine discharge pressure
→ faster recovery

Cooling does not allow cylinder overfill.

Exam Rule 8 - High Discharge Pressure Has a Cause

If the recovery machine trips on high pressure, check:

• Hot cylinder.
• Full or overfilled cylinder.
• Closed cylinder valve.
• Hose restriction.
• Noncondensables.
• Incorrect valve position.
• Poor machine cooling.

Do not bypass the high-pressure safety control.

Exam Rule 9 - Do Not Mix Refrigerants

known refrigerant A
+
known refrigerant B
→ do not intentionally mix

Use correctly identified cylinders and clean/dedicated recovery equipment as appropriate.

Common Mistakes and Confusing Points

Mistake 1: Calling Self-Contained Recovery “Recovery Using a Self-Contained Appliance”

The term describes the recovery equipment, not the appliance.

Mistake 2: Assuming the Appliance Compressor Must Run

A self-contained recovery machine does not require appliance-compressor assistance.

Mistake 3: Using the Recovery-Machine Compressor to Decide 80% Versus 90%

Wrong compressor.

The Type I percentage rule refers to:

compressor IN THE APPLIANCE

Mistake 4: Connecting Machine Outlet Back to the Appliance

The normal self-contained relationship is:

appliance
→ machine inlet
→ machine outlet
→ recovery cylinder

Mistake 5: Recovering Into a Disposable Cylinder

Disposable cylinders are not reusable recovery cylinders.

Mistake 6: Assuming Every Recovery Machine Uses the Same Cylinder Port

Follow manufacturer instructions.

Many common direct-recovery machines use the cylinder liquid port, but specialized procedures can differ.

Mistake 7: Choosing Cylinder Port by Hose Color

Identify the machine outlet and cylinder valve.

Do not infer cylinder function solely from hose color.

Mistake 8: Assuming High Cylinder Pressure Means the Cylinder Is Full

High pressure can also result from:

• High temperature.
• Noncondensables.
• Wrong refrigerant.
• Refrigerant mixture.

Use a scale for fill control.

Mistake 9: Assuming a Cold Cylinder Can Be Filled Beyond the Limit

Cooling lowers pressure.

It does not increase the allowable fill mass beyond the applicable limit.

Mistake 10: Cooling a Cylinder With an Unsafe Improvised Method

Use only safe, approved cooling practices.

Do not damage the cylinder or its valves.

Mistake 11: Bypassing a Recovery-Machine High-Pressure Cutout

Correct the cause of high discharge pressure.

Do not defeat the protection.

Mistake 12: Ignoring a Closed Cylinder Valve

A closed discharge path can rapidly raise recovery-machine discharge pressure.

Verify the connection and valve sequence before recovery.

Mistake 13: Treating Pressure-Temperature Mismatch as Proof of Air

It is a diagnostic clue.

Confirm refrigerant identity, temperature stabilization, blend behavior, and instrument accuracy.

Mistake 14: Purging Noncondensables by Venting Refrigerant

Do not intentionally vent recovered refrigerant.

Handle contaminated refrigerant through the proper recovery/reclamation pathway.

Mistake 15: Reusing a Recovery Cylinder Without Knowing Its Contents

Cylinder contents must be identified.

Unknown or mixed refrigerants should not be added to a clean known-refrigerant cylinder.

Mistake 16: Changing Refrigerants Without Clearing the Recovery Machine

Residual refrigerant can cross-contaminate the next cylinder and appliance.

Follow the machine manufacturer’s clearing procedure.

Mistake 17: Assuming a Machine Approved for One Refrigerant Is Automatically Safe for a Flammable Refrigerant

Verify machine approval for the refrigerant and safety class.

Mistake 18: Confusing the Section 7.6 Nonpressurized Container With a Normal Self-Contained Recovery Cylinder

Section 7.6:

special passive/system-dependent example
→ nonpressurized recovery container

Section 7.7:

self-contained recovery machine
→ commonly pressurized reusable recovery cylinder

Concept-Check Questions

Question 7.7-1

Which statement best defines self-contained recovery equipment?

A. Equipment that must use the appliance compressor to remove refrigerant

B. Equipment capable of removing refrigerant without assistance from components contained in the appliance

C. Any recovery cylinder with two valves

D. A vacuum pump connected directly to atmosphere

Question 7.7-2

In a typical self-contained recovery machine, what provides the primary refrigerant-moving force?

A. The appliance evaporator fan

B. The appliance compressor

C. The recovery machine’s independent compressor or pumping mechanism

D. The recovery cylinder color

Question 7.7-3

A small appliance has a failed compressor and is recovered with a self-contained machine manufactured in 2025. Under the percentage-recovery pathway, which compressor condition controls the EPA Type I percentage?

A. The recovery-machine compressor, so 90% always applies

B. The appliance compressor, so the nonfunctioning-compressor requirement applies

C. The recovery-cylinder pressure

D. The condenser fan condition

Question 7.7-4

What is the best general rule for choosing the recovery-cylinder port connected to the recovery-machine outlet?

A. Always use the vapor port.

B. Always use the liquid port regardless of machine instructions.

C. Use the cylinder port specified by the recovery-machine manufacturer for the selected recovery procedure.

D. Use whichever port has the shortest hose.

Question 7.7-5

A stabilized recovery cylinder containing a known refrigerant shows pressure substantially higher than the expected saturation pressure for its temperature. What is one possible explanation?

A. Noncondensable gas is present.

B. The refrigerant has no vapor pressure.

C. The cylinder is automatically empty.

D. The appliance compressor must be functioning.

Question 7.7-6

Why can cooling a recovery cylinder increase recovery speed?

A. It raises cylinder pressure.

B. It lowers cylinder pressure and therefore reduces recovery-machine discharge pressure.

C. It increases the allowable cylinder fill above 100%.

D. It changes the refrigerant into nitrogen.

Question 7.7-7

A recovery machine repeatedly trips on high discharge pressure. Which is a reasonable item to check?

A. Whether the recovery cylinder is hot or overfilled

B. Whether the cylinder valve is closed or restricted

C. Whether noncondensables may be increasing cylinder pressure

D. All of the above

Question 7.7-8

Which practice best reduces refrigerant cross-contamination?

A. Mix all recovered refrigerants into one cylinder.

B. Identify refrigerant, use an appropriate labeled cylinder, and follow the recovery-machine clearing procedure before changing refrigerants.

C. Vent the recovery machine after every job.

D. Rely only on cylinder paint color.

Answers and detailed explanations will be provided in 7.12 - Answers and Explanations.md.

Section Summary

A self-contained recovery machine removes refrigerant without requiring assistance from components inside the appliance.

The fundamental relationship is:

APPLIANCE
→ SELF-CONTAINED RECOVERY MACHINE
→ RECOVERY CYLINDER

The machine commonly contains an independent recovery compressor that:

draws refrigerant from appliance
→ compresses refrigerant
→ discharges refrigerant to recovery cylinder

The appliance compressor does not have to provide the recovery force.

However, the condition of the appliance compressor still matters when determining the current Type I percentage-recovery requirement.

For post-November 15, 1993 recovery equipment:

appliance compressor functioning
→ 90%

appliance compressor not functioning
→ 80%

or the applicable:

4 in. Hg vacuum

alternative.

Self-contained recovery commonly uses an approved pressurized reusable recovery cylinder.

The correct cylinder port should be determined from the recovery-machine manufacturer’s instructions. Many conventional direct-recovery machines connect:

machine OUTLET
→ cylinder LIQUID port

but this should not be taught as a universal connection for every recovery machine or specialized procedure.

As recovery continues:

cylinder temperature rises
→ cylinder pressure rises
→ machine discharge pressure rises
→ recovery slows

Approved cylinder cooling can help:

cool cylinder
→ lower cylinder pressure
→ lower discharge pressure
→ faster recovery

Noncondensables such as air can also raise recovery-cylinder pressure.

For a known, stabilized refrigerant:

measured cylinder pressure
>
expected saturation pressure
→ possible noncondensables

Finally, avoid refrigerant cross-contamination:

identify refrigerant
→ use correct cylinder
→ do not mix refrigerants
→ clear recovery equipment correctly between refrigerants

The next section applies the Type I material to complete service and disposal scenarios.

See Section 7.8 - Type I Service and Disposal Scenarios.

References

Current Regulatory and EPA Sources

1. Electronic Code of Federal Regulations, 40 CFR § 82.152 — Definitions, current definitions of self-contained recovery equipment, system-dependent recovery equipment, recover, recovery efficiency, small appliance, and low-loss fitting. Verified August 11, 2026.
   https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.152

2. Electronic Code of Federal Regulations, 40 CFR § 82.156 — Proper evacuation of refrigerant from appliances, especially current small-appliance recovery requirements, system-dependent-equipment limitation, and manufacturer-direction requirement. Verified August 11, 2026.
   https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-82/subpart-F/section-82.156

3. U.S. Environmental Protection Agency, Test Topics — Section 608 Technician Certification, current Core and Type I recovery topics including self-contained versus system-dependent recovery equipment, avoiding refrigerant mixing, recovery-speed factors, recovery-cylinder safety, use of pressure-temperature relationships to detect noncondensables, and Type I compressor/recovery distinctions. Verified August 11, 2026.
   https://www.epa.gov/section608/test-topics

4. U.S. Environmental Protection Agency, Refrigerant Recovery and Recycling Equipment Certification, current equipment-certification requirements and small-appliance equipment standards. Page last updated July 6, 2026; verified August 11, 2026.
   https://www.epa.gov/section608/refrigerant-recovery-and-recycling-equipment-certification

5. U.S. Environmental Protection Agency, Stationary Refrigeration Service Practice Requirements, current small-appliance recovery requirements and requirement to use recovery equipment according to manufacturer directions. Verified August 11, 2026.
   https://www.epa.gov/section608/stationary-refrigeration-service-practice-requirements

Primary Equipment-Procedure Reference

6. Appion, G5Twin Refrigerant Recovery Machine Operation Manual, current manufacturer operating instructions used as a specific example of a direct-recovery connection in which the recovery-machine output is connected to the Liquid Port on the Recovery Cylinder. This manufacturer-specific example is not treated as a universal connection rule for all recovery machines.
   https://appiontools.com/content/Manual%20_%20G5Twin_9_1_23.pdf

Project Cross-References

7. Section 3.4 - Refrigerant Identification.

8. Section 3.6 - Moisture Acid and Noncondensables.

9. Section 5.2 - Recovery Equipment Categories.

10. Section 5.5 - Recovery Methods and Recovery Speed.

11. Section 5.6 - Recovery Cylinders.

12. Section 7.3 - Type I Recovery Requirements.

13. Section 7.4 - Access Fittings and Process Stubs.

14. Section 7.5 - Recovery with an Operating Compressor.

15. Section 7.6 - Recovery with a Failed Compressor.

16. Section 7.8 - Type I Service and Disposal Scenarios.