EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Easy
A technician is performing a leak test on a low-pressure chiller using soap bubbles. At what pressure should the system typically be pressurized for this type of test?
- ABelow 0 psig (in a vacuum)
- BAt the system's normal operating discharge pressure
- CBetween 0 and 10 psig
- DAbove 30 psig
Show answer & explanationAnswer & explanation
Correct answer: C. Between 0 and 10 psig
Low-pressure chillers should be pressurized between 0 and 10 psig for leak testing. Pressurizing above 10 psig can cause the rupture disc to fail, leading to refrigerant release.
Why the other options are wrong
- A. A vacuum cannot be used for a soap bubble leak test, as it requires positive pressure.
- B. Normal operating discharge pressure is typically much higher and would exceed the safe leak test pressure for low-pressure systems.
- D. Pressurizing above 10 psig could rupture the low-pressure chiller's rupture disc.
Low-Pressure Leak Test Pressure
For low-pressure chillers, leak tests using positive pressure (like nitrogen) should be conducted between 0 and 10 psig to prevent damage to the system's rupture disc.
- 0-10 psig is the safe range for positive pressure leak tests.
- Exceeding 10 psig risks rupturing the disc.
- Often uses nitrogen for pressurization.
Memory trick: Don't 'POP' the chiller with too much pressure, keep it low and slow.