Natural sources of ionizing radiation include radioactive elements in the crust of the earth and the human body.

When radiation comes in contact with or is absorbed by matter, that material is said to be radioactive.

RTUs with hot water systems usually use a nonfreezing solution composed of water and _____ in the piping.

A common time when a compressor’s cylinders are unloaded is _____.

If a low pressure pushing against the bellows of a pressure water valve began to increase, the valve should _____.

The capacity of screw compressors is controlled with _____.

Cooling tower water that is intentionally drained to reduce mineral concentrations is called _____.

Purge units are designed to remove noncondensables from a(n) _____.

The purpose of a compression chiller economizer is to improve system efficiency by _____.

Cylinder unloading is used on _____ compressors.