How does a low water cut-off work?

A low-water cutoff is a mechanical device (usually a float switch) that is used to turn off the burner or shut off fuel to a boiler to prevent it from running once the water drops below a certain point. If a boiler is “dry-fired” (burned without water in it) it can suffer rupture or catastrophic failure.

How many low water cut outs are required on a boiler?

Some jurisdictional authorities require two functioning low-water fuel cutoffs on each boiler. In addition, the second low water fuel cutoff must be equipped with a manual reset in many instances.

How do you test a low water cut-off switch?

To perform a standard low-water test, your boiler needs to be set at a reduced firing rate (50% or lower). Then, simply open the low-water cutoff blowdown valve and monitor the sight glass to make sure the water is draining rapidly.

What does it mean when boiler says low water?

A low water condition in a boiler happens when the water level drops below the lowest permissible water level, or even below the top of the tubes, allowing the tubes to overheat. In fact, if the water gets lower than the main firing tube, or “Morrison tube,” the steel itself may fail.

Why does my boiler say low water?

What causes low water in boiler?

Low boiler pressure means the amount of water circulating in your system has dropped. There can be two main causes behind low boiler pressure, which follow below. A Leak in the System: A water leak in the system can be the cause behind low boiler pressure. A water leak may not always be easy to find.

What causes low water level in boiler?

Where boilers are operated without constant supervision (which includes the majority of industrial boilers) low water level alarms are required to shut down the boiler in the event of a lack of water in the boiler. Low level may be caused by: A feedwater shortage in the feedtank. Failure of a feedpump.