XV. 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 V8 Series manual XV. LOW Water CUT OFF Lwco, When
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V8 Series specifications

The Burnham V8 Series is a prestigious line of oil-fired boilers renowned for their efficiency, reliability, and advanced design features. Tailored for residential and light commercial applications, this series exemplifies the perfect blend of tradition and modern technology, ensuring long-term performance and comfort for users.

One of the hallmark features of the Burnham V8 Series is its exceptional cast iron construction, which provides durability and superior heat retention. This robust design allows for an extended lifespan while ensuring that the boiler can withstand the rigors of daily use. The cast iron sections are engineered to facilitate optimal heat transfer and efficiency.

The V8 Series boasts an impressive fuel efficiency rating, often exceeding 85%. This high efficiency is achieved through a combination of advanced combustion technology and the boiler's thoughtful design, which minimizes heat loss. Users benefit not only from lower energy bills but also from a reduced environmental footprint, making the Burnham V8 Series a sustainable choice for heating solutions.

In terms of technology, the Burnham V8 Series features a standing pilot ignition system or an optional intermittent ignition device that enhances safety and efficiency. The advanced burner design allows for smooth operation and excellent fuel utilization, further contributing to the overall economy of the system.

Another notable characteristic is the versatility of the Burnham V8 Series. It can be easily adapted to work with various heating systems, including hot water heating applications. Its compatibility with different fuels, such as natural gas or oil, gives users the flexibility to choose the best energy source for their needs, providing longevity and value.

The installation process is made straightforward with ample connectivity options for plumbing and flue. Its compact design enables easier placement within homes or commercial spaces without compromising performance. Furthermore, the boiler is backed by extensive warranties, ensuring peace of mind for homeowners and businesses alike.

In conclusion, the Burnham V8 Series stands out as a reliable and efficient heating solution, blending robust construction with advanced technology. Its commitment to performance, versatility, and efficiency makes it an excellent choice for meeting the heating demands of various applications while promoting environmental responsibility. Whether for a single-family home or a light commercial building, the Burnham V8 Series remains a trusted leader in the industry.
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