What is LWCO in boiler?
What is LWCO in boiler?
To help prevent damage, boilers are fitted with low water cutoffs (LWCOs). These devices are intended to detect the low water condition and shut down the boiler. The burner remains off until the water returns, then the burner is allowed to fire normally.
What is LWCO?
A low water cutoff (LWCO) device is positioned above the lowest possible water level of a pressure vessel, used to monitor the water level inside a boiler and shut off fuel or electrical power to the burner to cease combustion when the water level drops below a safe operating condition – also known as dry firing.
How does a LWCO work?
An LWCO device actively monitors the water level in the boiler, then cuts power and shuts down the system if the level drops below a safety threshold. Experts view the feature as virtually standard.
How do you test LWCO?
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 happens if a boiler runs out of water?
Boiler Failure If a boiler has enough water, the steel will never reach temperatures high enough to weaken it. In a dry fire accident, there is no water to moderate the temperature. As a result, the boiler’s steel can overheat, warp and crack at the welds.
How does a low water cut off probe work?
Probe Style LWCO A probe uses the boiler’s water to complete an electrical circuit. As long as water covers the probe, the electronic circuit will be maintained. If the water level drops below the probe, the circuit is broken, shutting down the burner and protecting the boiler.
What causes low water in boiler?
Some common causes of low-water conditions include: Feedwater pump failure. Control valve failure. Loss of water to the deaerator or make-up water system.
Can a boiler run without water?
Most boilers lose a certain amount of water during normal operation. The safety system includes a low-water cutoff that shuts down the boiler if there is too little water. If the safety system fails and the boiler continues to run without enough water, it could have a dry fire accident.
What causes a boiler to lose water?
Modern boilers require constant water pressure in order to function properly. There are two main problems that typically cause a loss of pressure – water escaping somewhere in the system or a failure of the expansion valve and resulting damage to the pressure relief valve.
Does a hot water boiler have a low water cut-off?
ASME (American Society of Mechanical Engineers) Steam heating boilers of any size, regardless of where they are installed, must have a low water cut-off per ASME BPVC.
