Steam Boiler Water Level Control

Boiler water level control on the boiling point primary and low water cutoff devices are arguably the most important safeties on a boiler because if we don't have water in the boiler it's gonna be rapidly destroyed by the temperature of combustion this is an example of a secondary low water cutoff probe housing and we'll be talking about probe-type low water cut-offs today one advantage of using an externally mounted secondary low water cut off even if it's a probe type is that allows us to daily blowdown and test operation of the safety one difference between a probe-type secondary low water cutoff in a float type is that a float type secondary will have a manual reset button in the immediate vicinity of the device on a probe-type low water cut off we have a relay that's enabling or disabling the limit circuit and so that reset button may be remotely located in this case it's over on this panel this unit has a series 1 Warwick low water cutoff relay those were phased out about three years ago and the wiring on them is significantly different.

The modern style or the replacement and so it's critically important to understand that if you're going to change out an older style relay one advantage of the probe type low water cutoff devices that there are one is this externally mounted pot another example is housing mounted on the centerline of the boiler and you can also put multiple probes in an external pot as you would frequently see on a water tube boiler let's take a look at some of the internal parts of the probe assemblies that we've been looking at this is an example of the top housing these have threaded inserts which the probes fit into we threaded in an important part of assembling these is this copper washer because that's what forms the mechanical seal to make it pressure tight so don't lose your copper washer the probes are available in to piece or single piece assemblies all probes are originally three feet or longer when you order them so it's important that you know how long the probes are supposed to be on your boiler I would recommend removing them every open and close if you order a low water cutoff probe it's going to be a standard length you're gonna be responsible for cutting that to the appropriate length for your boiler so it's very important that you know what that proper length is one great way to find that out is during your open and close for inspection remove the probe clean it check for pitting maybe clean it with sandpaper and measure it and you can actually take a sharpie write that measurement down on the jacket of your boiler.

Right next to the probe housing and then you'll have that for the future this is a Warwick probe housing other manufacturers may have different thread connections on the probe devices wark uses a machined thread which is why we rely on the washer to make a seal but some manufacturers will have a tapered pipe thread in both the fitting and on the electrode so they're not interchangeable many times one grant one rod will be used as a grounding surface on a single probe installation the boiler itself is used as the ground for the electrical circuit the way this operates is as the water rises and forms a junction between the two probes that connection is recognized by the relay and it pulls in and completes either the operating limits circuit or a high water alarm whatever the case may be understanding how these components work together is an important part of checking the Safety's on your boiler and having safe operation well appreciate Jude hanging out with us today and talk a little bit about water level control.