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.

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.

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

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

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

Relief valves should be manually tested every 30 days as recommended by the ASME Code.

A boil-out procedure is performed when a new boiler is installed or repaired.

Relief valves should be manually tested every 30 days as recommended by the ASME Code.

A gas law relates to events that occur as heat is generated by the combustion of a fuel and is used to produce steam or hot water in a boiler.