A forced draft fan is located in the breeching.

Centrifugal compressors generally do not have a great deal of compressive power, but they can handle a large volume of refrigerant.

Boiler room accidents can occur at any time.

A modulating pressure control regulates the burner firing rate of high fire to low fire by sending an electrical signal that controls a modulating motor connected to a combustion equipment control linkage.

In a high pressure gas system, gas is supplied through a high pressure gas main at a higher pressure than that within a typical residential gas supply line.

Pipe-mounted circulating pumps are smaller pumps that are attached directly to the piping.

In a high pressure gas system, gas is supplied through a high pressure gas main at a higher pressure than that within a typical residential gas supply line.

If the top line to a gauge glass is closed or clogged, the glass will fill with water.

Pipe-mounted circulating pumps are smaller pumps that are attached directly to the piping.

___ air controls combustion efficiency and is usually introduced into a furnace from below the burner.