EPA Section 608 Universal Certification ExamType I (Small Appliances)Easy
A technician is installing a new compressor in a small appliance that uses R-134a. After replacement, what is the primary purpose of evacuating the system to a deep vacuum?
- ATo remove all moisture and non-condensables from the system.
- BTo pre-charge the system with a small amount of refrigerant.
- CTo verify the system can hold a positive pressure.
- DTo test the new compressor's pumping efficiency.
Show answer & explanationAnswer & explanation
Correct answer: A. To remove all moisture and non-condensables from the system.
The primary purpose of evacuating an HVAC/R system to a deep vacuum is to remove all moisture (which becomes ice and causes blockages) and non-condensable gases (like air, which increases head pressure and reduces efficiency) from the system, ensuring optimal performance and longevity.
Why the other options are wrong
- B. Pre-charging occurs after evacuation and leak checking, not as the purpose of evacuation.
- C. Verifying positive pressure is part of leak checking after evacuation, not the primary purpose of evacuation itself.
- D. Compressor pumping efficiency is tested during operation, not through evacuation.
Deep Vacuum Evacuation Purpose
The primary purpose of pulling a deep vacuum on an HVAC/R system is to remove all moisture and non-condensable gases, such as air, which can cause system inefficiencies and damage.
- Moisture turns to ice, causing blockages.
- Non-condensables increase head pressure and reduce efficiency.
- A deep vacuum lowers the boiling point of water, allowing it to be removed as vapor.
Memory trick: Deep vacuum's quest: remove all the moisture and air, putting performance to the test!