Why is the low-side gauge called a compound gauge?
Refrigeration · EPA 608 Core. The correct answer, and the reasoning behind it.
The refrigeration cycle, refrigerant states and pressures, gauges and leak detection.
The question
Why is the low-side gauge called a compound gauge?
- It reads pressure and temperature of two refrigerants
- It reads both pressure and vacuumCorrect answer
- It combines a gauge with a sight glass
- It can be used on either side of the system
Why “It reads both pressure and vacuum” is correct
A compound gauge reads positive pressure in psig and also vacuum below atmospheric pressure in inches of mercury. That lets the low side be read during normal operation and during recovery or evacuation.
Source: EPA: Test Topics
Why the other answers are wrong
- It reads pressure and temperature of two refrigerants — Dual temperature scales do not make a gauge "compound".
- It combines a gauge with a sight glass — A sight glass is a separate component.
- It can be used on either side of the system — The low-side gauge is meant for the low side; the high-side gauge has a higher range.
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