Boilers are ever present in our everyday lives. Whether it’s your residential boiler located in your basement, to large commercial boilers found in hospitals, hotels and other large buildings. These boilers provide hot water or steam needed for building heating purposes or for domestic hot water. In order to operate correctly and safely, they require liquid level sensors. Especially the use of an approved low water cutoff. Without this low water cutoff sensor, boilers could run out of water which creates a condition known as dry fire when the heating tubes are exposed. This is very dangerous and could lead to the boiler over pressurizing and exploding!
Challenge: Finding an approved, affordable, and reliable sensor to provide low water cutoff protection in the boiler industry.
Solution: Warrick’s line of Conductivity Based Liquid Level Controls is an excellent solution. Specifically, Warrick Series 26 and Series DF (Dual Function) are conductivity-based relays and are UL approved to meet the CSD1 requirement to be used as a boiler low water cutoff. Safety is critical for boiler water level indication, so the Series 26 and Series DF meet the requirement for built-in redundancy in the control circuitry.
The Series 26 relay is highly configurable with different sensitivity options, supply voltages, mounting styles, and the ability to be mounted in an enclosure. It can be configured as an open board style relay or placed in a module for ease of installation. The Series DF (Dual Function) builds on the specifications of the Series 26 with the added feature of pump control. Typically, in the boiler application, not only is low water cutoff critical, but so is the feedwater control. The feedwater is to resupply the boiler with water as it loses water through evaporation. The Series DF comes standard with a separate relay built onto the board that can control a pump or valve for this refilling operation. If you are familiar with the Series 16 relay, that is what the Series DF is, a combination of the Series 16 and 26 into one boiler controller. This saves crucial space in cabinets and simplifies the controls into one relay.
In addition, the Series 26 and Series DF both have the capability to be configured with time delays, automatic rests, manual resets, and a power outage feature. These configurable options help ensure a simple and fool proof operation for any operator!
Additional Sensors used in boilers:
- Series 3E, 3F Fittings: Hold the probes above the tank and provide a junction point.
- Series 3R Probes: Connect to the fittings and are the actual sensor within the tank.
- Series 16 Relay: Controller for boiler feedwater
- Series 3K Fitting: Side chamber contains 3H probes allow for mounting onto side of boiler instead of the top.