- AIt saves money
- It creates unknown pressure-temperature relationships and may damage equipment
- CIt increases system efficiency
- DMixing is allowed with similar refrigerants
Correct answer
It creates unknown pressure-temperature relationships and may damage equipment
Why
Mixing refrigerants creates unknown pressure-temperature relationships, unpredictable performance, and potential equipment damage. Mixed refrigerants must be reclaimed or destroyed.
The concept behind this question
Recovery technique depends on the appliance and how much refrigerant it holds. The practical distinction is between system-dependent (passive) recovery, which relies on the appliance's own compressor or pressure and is limited to small appliances, and self-contained (active) recovery, which uses a powered recovery machine and is required for larger equipment. Recovery equipment must be certified to the applicable standard, and required evacuation levels vary with appliance size and type.
More questions on this topic
- What type of recovery equipment must be used for refrigerants?
- What must recovery equipment be capable of achieving?
- What is the required recovery efficiency for small appliance recovery equipment manufactured after November 15, 1993 when the compressor is operating?
- What is a self-contained recovery device?
- What is a system-dependent recovery device?
- What should be done before recovering refrigerant from a system with a burned-out compressor?
Exam-style practice question. Not an official EPA exam question.