Title: (Optional) Identify high-pressure and low-pressure recovery techniques and requirements.
Course: Heating, Ventilation, Air Conditioning, and Refrigeration I (17056-I) > Section: Complying with EPA Laws and Regulations

Identification should include a selection from the following, taken directly from the EPA's Ozone Layer Protection—Regulatory Programs:

High-pressure methods should include the following:

- Recovering liquid at beginning of recovery process speeds up process
- Other methods for speeding recovery (chilling recovery vessel, heating appliance or vessel from which refrigerant is being recovered)
- Methods for reducing cross-contamination and emissions when recovery or recycling machine is used with a new refrigerant
- Need to wait a few minutes after reaching required recovery vacuum to see if system pressure rises (indicating that there is still liquid refrigerant in the system or in the oil)

Low-pressure methods should include the following:

- Recovering liquid at beginning of recovery process speeds up process
- Need to recover vapor in addition to liquid
- Need to heat oil to 130 degrees Fahrenheit before removing it to minimize refrigerant release
- Need to circulate or remove water from chiller during refrigerant evacuation to prevent freezing
- High-pressure cut-out level of recovery devices used with low-pressure appliances

High-pressure requirements are variable depending on

- disposal needs
- major vs. non-major repairs
- leaky vs. non-leaky appliances
- appliance (or component) containing less vs. more than 200 pounds
- recovery/recycling equipment built before vs. after November 15, 1993
- definition of major and non-major repairs
- prohibition on using system-dependent recovery equipment on systems containing more than 15 pounds of refrigerant.

Low-pressure requirements include all of the high-pressure variables except for the last bullet, with the addition of

- allowable methods for pressurizing a low-pressure system for a non-major repair (controlled hot water and system heating/pressurization device such as Prevac)
- the need to wait a few minutes after reaching required recovery vacuum to see if system pressure rises (indicating that there is still liquid refrigerant in the system or in the oil).

Process/Skill Questions:

- Who certifies recovery equipment?
- How often should the filter be changed on the recovery machine?
- What can minimize the loss of oil from a refrigeration unit when recovering refrigerant?