Flow

Drum level

Cut-off

Float

Differential pressure

Stop the feed pump thereby preventing damage to it.

Open a make-up solenoid.

Cause the make-up valve to close.

Sound an alarm.

Shut off the boiler.

A deaerator

Fully modulating burners

Steam pressure, regulating valves

Multiple boilers

A condensate receiver

Raise the pH of condensate

Absorb carbon dioxide

Eliminate boiler pitting

Can cause return grooving

Lower the pH of boiler water

Be a normally closed valve.

Not open until the level is well below the feed pump cut-in level.

Not be deemed a stand-by device.

Open just after the low-water cutoff switch opens.

Be located above the water column.

Require manual action to open.

Open if the boiler trips due to low water.

Eliminate the need for a second low-water fuel cutoff.

Open before the low-water cutoff operates.

Prevent low-water conditions.

Can cause pitting on the return lines.

Necessitates the installation of a deaerator.

Causes grooving of the condensate lines.

Is removed with amines.

Will cause pitting in a boiler.

Loss of condensate to the sewer.

Unacceptable high steam pressures.

Loss of make-up water.

Low make-up water flow rates.

High boiler water level.

Only be installed on multiple-boiler systems.

Replace the feedwater check valve.

Prevent steam from entering a steam pressure gauge.

Ensure continuous circulation of a hot water system.

Prevent boiler water level from going below the lowest safe water level.

A common feedwater control valve.

Problems controlling water level.

Independent boiler feedwater controls.

Individual feedwater systems.

Separate condensate receivers.

an economiser

steam pressure regulating valves

a condensate receiver

multiple boilers

a deaerator

loss of make-up water

unacceptable high steam pressures

high boiler water level(s)

low make-up water flow rates

loss of condensate to the sewer

a prepurge will not be necessary

the feedwater flow will also stop

level must be restored to above the cut-off line before the unit can be restarted

it can be restarted by simply resetting the cut-off switch

a manual reset switch must be used

must be deaerated

requires daily close scrutiny of chemical values

is a high make-up percentage

requires preheating in an economizer

is usually condensate

maintains equal flow of condensate to multiple boilers

eliminate the need for a make-up level control valve

maintain make-up flow equal to condensate flow

will dampen level fluctuations

keep receiver level equal to boiler level