EPA 608 Technician Certification Small Appliance Recovery Techniques and Safety Summary

When the compressor does not work, refrigerant cannot be pushed through the system. Installing access valves on both the high and low sides lets refrigerant come out of both parts of the system.

Wrong choices

• Install an access valve on the low side only: With only one valve, much of the refrigerant stays trapped.
• Run the broken compressor anyway: A compressor that does not work cannot move refrigerant.
• Install an access valve on the high side only: With only one valve, much of the refrigerant stays trapped.

System-dependent recovery equipment needs help from the appliance, such as its compressor or internal pressure, to remove refrigerant. Self-contained equipment has its own compressor and can work without the appliance's help.

Wrong choices

• Equipment that cleans refrigerant to reclaim standards: Reclaiming is done by certified reclaimers, not recovery equipment.
• Equipment with its own built-in compressor: Equipment with its own compressor is self-contained (active) equipment.
• Equipment that is permanently mounted on a rooftop: Mounting location does not define system-dependent equipment.

Solderless piercing access valves are meant for temporary use. They tend to leak over time, so EPA's test topics say to remove them when service is finished.

Wrong choices

• Tighten them once a year: Tightening does not fix the leak risk.
• Paint them to prevent rust: Painting does not stop a piercing valve from leaking.
• Leave them on for the next service call: Piercing valves can leak if left on.

EPA's test topics name HFC-134a (R-134a) as the likely substitute for CFC-12 (R-12). Newer household refrigerators may also use isobutane (R-600a).

Wrong choices

• R-22: R-22 is an HCFC used mainly in air conditioning.
• R-410A: R-410A is a high-pressure refrigerant for air conditioning.
• R-123: R-123 is used in low-pressure chillers.

With passive recovery, a working compressor in the appliance should be run to push the refrigerant out of the system and into the recovery container.

Wrong choices

• Heat the recovery container: Heating the container raises its pressure and slows recovery.
• Open the system to the air first: Opening the system would vent refrigerant.
• Leave the compressor off for the whole recovery: The working compressor helps move refrigerant, so it should be used.

At high temperatures, such as near a torch flame, refrigerants can decompose into dangerous products such as hydrochloric and hydrofluoric acid, and for some older refrigerants phosgene gas. Ventilate the work area and recover refrigerant before brazing.

Wrong choices

• It becomes nitrogen: Refrigerant does not turn into nitrogen.
• It turns into harmless water vapor: Refrigerant does not turn into water vapor.
• Nothing; refrigerants are fully stable at any temperature: Refrigerants break down at high temperatures.

Self-contained recovery equipment can remove refrigerant without the help of parts in the appliance, because it has its own compressor or pump. It can be used on appliances of any size.

Wrong choices

• A cylinder with no valves: A cylinder with no valves cannot be used for recovery.
• A plastic bag used to catch refrigerant: Bags are sometimes used as passive containers, but they are not self-contained equipment.
• Equipment that depends on the appliance's compressor: Depending on the appliance's compressor describes system-dependent equipment.

Hydrocarbon refrigerants such as isobutane (R-600a) and propane (R-290) are flammable. Follow the manufacturer's instructions, keep ignition sources away, and use tools rated for flammable refrigerants.

Wrong choices

• It reacts with water to form acid: This is not its main hazard.
• It is extremely toxic in tiny amounts: Isobutane is not highly toxic; its main hazard is fire.
• It is a very high-pressure refrigerant: Isobutane is not a very high-pressure refrigerant.

40 CFR 82.156(e) says system-dependent recovery equipment may not be used on appliances with a full charge of more than 15 pounds, unless it is a permanently attached pump-out unit. Household refrigerators hold far less.

Wrong choices

• Rooftop units do not contain refrigerant: Rooftop units do contain refrigerant.
• Passive recovery is only allowed outdoors: There is no indoor or outdoor rule.
• Rooftop units have no compressor: Rooftop units do have compressors.

Before opening a small appliance, the technician must recover the refrigerant to the required level (80 or 90 percent, or 4 inches of mercury vacuum). This also prevents toxic decomposition from the torch's heat.

Wrong choices

• Heat the compressor with the torch: Heating with a torch before recovery creates a fire and decomposition hazard.
• Open the line and let the refrigerant escape: Letting refrigerant escape is illegal venting.
• Add more refrigerant so the pressure stays positive: Brazing on a charged system is dangerous and can break down refrigerant.