VI. Low Water Cut Off (LWCO)

WARNING

DO NOT ATTEMPT to cut factory wires to install an aftermarket Low Water Cut Off (LWCO). Only use connections specifically identified for Low Water Cut Off.

In all cases, follow the Low Water Cut Off (LWCO) manufacturer's instructions.

When

A low water cutoff is required to protect a hot water boiler when any connected heat distributor (radiation) is installed below the top of the hot water boiler (i.e. baseboard on the same floor level as the boiler). In addition, some jurisdictions require the use of a LWCO with a hot water boiler.

Where

The universal location for a LWCO on both gas and oil hot water boilers is above the boiler, in either the supply or return piping. The minimum safe water level of a water boiler is at the uppermost top of the boiler; that is, it must be full of water to operate safely.

What Kind

Typically, in residential applications, a probe type LWCO is used instead of a float type, due to their relative costs and the simplicity of piping for a probe LWCO.

How to Pipe

A “tee” is commonly used to connect the probe LWCO to the supply or return piping, as shown below.

LWCO Location

Select the appropriate size tee using the LWCO manufacturer’s instructions. Often, the branch connection must have a minimum diameter to prevent bridging between the probe and the tee. Also, the run of the tee must have a minimum diameter to prevent the end of the probe from touching or being located too close to the inside wall of the run of the tee.

Ideally, manual shutoff valves should be located above the LWCO and the boiler to allow for servicing. This will allow probe removal for inspection without

draining the heating system. Many probe LWCO manufacturers recommend an annual inspection of the probe.

How to Wire

LWCO’s are available in either 120 VAC or 24 VAC configurations. The 120 VAC configuration can be universally applied to both gas and oil boilers by wiring it in the line voltage service to the boiler (after the service switch, if so equipped).

The presence of water in a properly installed LWCO will cause the normally open contact of the LWCO to close, thus providing continuity of the 120 VAC service to the boiler.

It is recommended to supply power to the probe LWCO with the same line voltage boiler service as shown below.

Wiring of Typical LWCO

A 24 VAC LWCO is used primarily for gas fired boilers where a 24 volt control circuit exists within the boiler. However, a 24 VAC LWCO can only be used if the boiler manufacturer has provided piping and wiring connections and instructions to allow for this application.

How to Test

Shut off fuel supply. Lower water level until water level is BELOW the LWCO. Generate a boiler demand by turning up thermostat. Boiler should not attempt to operate. Increase the water level by filling the system. The boiler should attempt to operate once the water level is above the LWCO.

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Burnham SM-6 manual VI. Low Water Cut Off Lwco, When
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SM-6 specifications

The Burnham SM-6 is a high-performance modular boiler designed for commercial and industrial applications. Known for its efficiency and reliability, the SM-6 is engineered to meet a wide range of heating demands while maintaining low operational costs.

One of the standout features of the SM-6 is its modular design. This allows for scalable installations, catering to varying heating needs without requiring extensive modifications. The boiler can operate independently or in conjunction with other units, providing flexibility that is essential for industries with fluctuating demands.

In terms of technology, the Burnham SM-6 utilizes advanced combustion technology to achieve high efficiency rates. The unit typically operates with a stellar thermal efficiency of around 85% to 90%, minimizing fuel consumption and reducing greenhouse gas emissions. The incorporation of electronic ignition further helps in conserving energy, as it eliminates the need for a standing pilot light.

The SM-6 is made from high-quality materials designed for durability and long service life. The heat exchanger is constructed with durable steel, enabling it to withstand high temperatures and pressures. This robust construction ensures reliability in demanding environments, mitigating the risk of breakdowns and enhancing overall productivity.

Another key characteristic of the Burnham SM-6 is its user-friendly control system. The boiler is equipped with a state-of-the-art control panel that provides operators with real-time data on performance metrics. This allows for proactive maintenance and performance optimization, enhancing the overall operational efficiency of the system.

Safety is also a paramount consideration in the design of the SM-6. It includes multiple safety features, such as pressure relief valves and electronic safety checks, to prevent dangerous operating conditions. These features ensure that the boiler can run safely over extended periods, providing peace of mind for facility managers.

In conclusion, the Burnham SM-6 boiler stands out in the market for its modular design, high efficiency, durable construction, and advanced control technologies. Its versatile nature makes it an excellent choice for various applications, from manufacturing facilities to commercial buildings, ensuring it meets the heating requirements of diverse industries effectively. The combination of efficiency, reliability, and safety solidifies the Burnham SM-6 as a leading solution in the realm of heating systems.
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