EPA 608 Technician Certification Sample Questions and Explanations

40 CFR 82.154(a) says no one servicing, repairing, or disposing of an appliance may knowingly vent CFC, HCFC, or non-exempt substitute refrigerants such as HFCs. Only a short list of substitutes (for example CO2 or nitrogen, and some hydrocarbons in certain uses) is exempt.

Wrong choices

• Only CFCs and HCFCs: Most substitutes such as HFCs are also covered.
• Only refrigerants in systems over 50 pounds: The venting prohibition applies to appliances of every size.
• Only CFCs: The venting prohibition covers more than CFCs.

40 CFR 82.152 defines a small appliance as one that is fully manufactured, charged, and hermetically sealed in a factory with 5 pounds or less of refrigerant, such as household refrigerators, window air conditioners, dehumidifiers, and water coolers.

Wrong choices

• A field-assembled split system with 15 pounds or less: Field-assembled systems are not small appliances, and the limit is 5 pounds, not 15.
• Any appliance with less than 50 pounds of refrigerant: 50 pounds is a leak repair threshold, not the small appliance limit.
• Any appliance that plugs into a wall outlet: Plugging into an outlet does not make an appliance "small" under the rule.

Under 40 CFR 82.157(c), appliances with 50 or more pounds of ozone-depleting refrigerant must be repaired when the leak rate is over 10 percent for comfort cooling (and other appliances), 20 percent for commercial refrigeration, and 30 percent for industrial process refrigeration.

Wrong choices

• 30 percent: 30 percent is the trigger for industrial process refrigeration.
• 20 percent: 20 percent is the trigger for commercial refrigeration.
• 35 percent: 35 percent was an older trigger rate that no longer applies.

Because much of a low-pressure system runs below atmospheric pressure (in a vacuum), a leak lets air and moisture enter the system. These noncondensables collect in the condenser and must be removed by the purge unit.

Wrong choices

• The chiller pressure rises above 100 psig: A leak does not raise pressure that high.
• Refrigerant sprays out of the leak at high pressure: Parts of the system below atmospheric pressure draw air in rather than pushing refrigerant out.
• Nothing, because low-pressure systems cannot leak: Low-pressure systems can and do leak.

R-410A is a high-pressure refrigerant. Servicing or disposing of medium-, high-, or very high-pressure appliances (other than small appliances and motor vehicle systems) requires Type II certification, which is also included in Universal.

Wrong choices

• Section 609 (motor vehicle) certification: Section 609 is for motor vehicle air conditioning.
• Type III: Type III covers low-pressure appliances such as R-123 chillers.
• Type I: Type I covers only small factory-sealed appliances with 5 pounds or less.

Small appliances include window and room air conditioners, household refrigerators and freezers, dehumidifiers, under-counter ice makers, vending machines, and drinking water coolers, as long as they are factory-sealed with 5 pounds or less.

Wrong choices

• A 3-ton split-system central air conditioner: A split system is assembled and charged in the field, so it is not a small appliance.
• A packaged rooftop unit: Rooftop units usually hold more than 5 pounds and need Type II.
• A centrifugal chiller: Chillers are large appliances (Type II or Type III).

Supermarket and cold-storage systems are commercial refrigeration. With 50 or more pounds of ozone-depleting refrigerant, leaks must be repaired when the leak rate exceeds 20 percent per year.

Wrong choices

• 30 percent: 30 percent is the trigger for industrial process refrigeration.
• 15 percent: 15 percent was an older comfort cooling trigger.
• 10 percent: 10 percent is the trigger for comfort cooling and other appliances.

R-123 is an HCFC, so this chiller falls under 40 CFR 82.157. For comfort cooling appliances with 50 or more pounds, the leak repair trigger is 10 percent per year.

Wrong choices

• 15 percent: 15 percent was an older comfort cooling trigger.
• 20 percent: 20 percent is the trigger for commercial refrigeration.
• 30 percent: 30 percent is the trigger for industrial process refrigeration.

Strong sunlight high in the stratosphere breaks CFC and HCFC molecules apart and frees chlorine atoms. Each chlorine atom then breaks down ozone molecules. HFCs contain no chlorine, so they do not harm the ozone layer.

Wrong choices

• Fluorine: Fluorine is in CFCs, HCFCs, and HFCs, but it is not what breaks down ozone in these refrigerants.
• Carbon: Carbon is the backbone of the molecule and does not destroy ozone.
• Hydrogen: Hydrogen actually makes HCFCs break down sooner in the lower atmosphere, so less chlorine reaches the ozone layer.

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.