A technician is performing a pressure test on a new refrigeration system using nitrogen. What is the maximum safe test pressure for a low-pressure system (e.g., one designed for R-123) when using nitrogen?
- A10 psig
- B50 psig
- CThe manufacturer's recommended test pressure, typically not exceeding 10 psig for low-pressure systems.
- D150 psig
Show answer & explanationAnswer & explanation
Correct answer: C. The manufacturer's recommended test pressure, typically not exceeding 10 psig for low-pressure systems.
For any system, especially low-pressure systems, the maximum safe test pressure is always dictated by the manufacturer's recommendations. Over-pressurizing a low-pressure system, even with nitrogen, can cause severe damage or rupture, despite the general safe limit for low-pressure systems typically being around 10 psig.
Why the other options are wrong
- A. 10 psig is a common maximum for many low-pressure systems, but the absolute rule is the manufacturer's spec.
- B. 50 psig is too high for a low-pressure system and could cause damage.
- D. 150 psig is dangerously high for a low-pressure system and would certainly cause damage or rupture.
Low-Pressure System Test Pressure
When pressure testing a low-pressure refrigeration system (e.g., R-123 chiller) with nitrogen, the maximum safe test pressure is strictly governed by the manufacturer's specifications, typically not exceeding 10 psig to prevent damage to the system components.
- Always follow manufacturer's guidelines.
- Low-pressure systems are fragile.
- Over-pressurization can cause severe damage.
Memory trick: Manufacturer's word is gold, don't be bold.