Author Question: Semi-hermetic compressors on large commercial AC units use ________ to stage the compressor by ... (Read 53 times)

leo leo · **on:** Jul 27, 2018

Semi-hermetic compressors on large commercial AC units use ________ to stage the compressor by cutting out individual cylinders in response to load changes.

A) Unloaders B) King valves
C) Automatic expansion valves D) TXV valves

Question 2

There are no check valves or extra metering devices on most water-source packaged units because

A) most water-source packaged units use suction line accumulators and charge compensators.
B) its heat exchangers are most often made of copper, cupronickel, or stainless steel.
C) water-source packaged units have a much lower operating temperature range than air-source units.
D) most water-source packaged units use a single bi-flow thermostatic expansion valve.