In this guide we’ll walk you through everything there is to know about float operated controllers.
From the basics of how it works to step-by-step repairs and troubleshooting, you’ll gain a solid foundation of knowledge on how to operate and maintain Kimray’s float operated controllers.
Use the table of contents to skip to different sections of the learning path.
Currently using a Gen II? Upgrade to the new Gen 3 - our all-new liquid level controller that's even easier for operators to install and adjust in the field.
In this video, Mike explains how Kimray’s line of float operated liquid level controllers work. This includes:
These are pneumatic or electric level controllers and level switches. They are commonly referred to as pilots because they are not valves themselves, but they send a signal to a valve to open or close based off the liquid level that they’re sensing.
It’s like the idea of a light switch, where you have electricity running to the switch, but when the switch is off the electricity doesn’t go anywhere. Then, when you flip the switch on, it allows that electricity to go through the switch and up to the item that it’s controlling (e.g. a light bulb or fan).
The float or displacer sits inside of a pressurized vessel, and as the liquid level rises that displacer moves upward. That is what sends a signal to the valve to open so that the liquid will start dumping.
When it gets low enough, it sends a signal to the valve to close so that the water or oil can start filling up.
The most common application you’ll find on a production site is a separator.
In a two-phase separator, you’ll use one level controller to control the level between the oil and the gas.
In a three-phase separator, you’ll use two level controllers—one to control the water level and another to control the oil level.
In either application, a liquid level switch could be used as a high level or low level shutdown or both. These are used in case of a system failure. The high level shutdown prevents the vessel from overfilling. A low level shutdown prevents the vessel from emptying.
A liquid level switch can also be used in the same way on a heater treater as a low level or high level shutdown. A heater treater is essentially a separator that uses a fire tube to accelerate the process of separation in a dehydration system.
There are also several displacer options for different conditions, including:
For more information on how liquid level controllers and other products can be used across a variety of applications, check out our Product Applications Guide.
A pneumatic liquid level switch is a control device used as a high level and/or low level switch in a pressurized production vessel. The switch sends a pneumatic signal, which can be used to actuate a control valve open or closed.
A liquid level switch is used to maintain desired level in separators, scrubbers, treaters, and other vessels.
There are two types of liquid level switch: electric and pneumatic.
In Kimray's pneumatic liquid level switch, supply pressure comes in through the filter, into the pilot body, creating a force on the stem, keeping it closed.
The float lever is magnetically opposed to the magnet in the shuttle which has a check ball on the top and bottom to seal off the flow in either direction. In the closed position it repels the shuttle downward, blocking the flow of supply gas to the diaphragm.
As the liquid level rises and the float moves up, the float lever pivots down, repelling the shuttle up. This means the channel for the supply pressure to contact the diaphragm opens. This creates enough force to push the stem outward so that the supply pressure can flow to output. The diaphragm also creates a seal, which blocks the vent path.
A pneumatic dump valve then receives an output signal telling it to open, which dumps liquid—typically either oil or water—from the vessel.
As the liquid level and float move down, the lever pivots upward, repelling the shuttle back down. This blocks the pressure to the diaphragm, which allows the stem to close with the O-ring sealing on the beveled surface.
With pressure no longer on the supply side of the diaphragm, the pressure from the output port pushes the diaphragm to flow out to vent.
For manual actuation of the switch, after being installed in the vessel, there is a manual override button on the top.
The Kimray Pneumatic Level Switch comes direct-acting standard. However, you can easily switch it to indirect-acting by rotating the pilot body 180 degrees. If you need an extension to give the float more clearance, we offer a 3” extended version.
We also offer an electric version of the level switch.
If you need to control the level from outside of the vessel, we offer a compact, external float cage that works with both the pneumatic and electric level switch.
If you have questions about this or any other Kimray product, contact your local Kimray store or authorized distributor.
The Kimray Gen 3 Liquid Level Controller is a simple, versatile solution that delivers precise level control.
In this video, you'll learn how to easily configure, set up and operate the Gen 3.
The Gen 3 includes a 1/8" hex key for the pilot and lever fasteners, and it can be conveniently stored inside the enclosure as shown in the video.
In addition to this tool, you will also need the following:
You can purchase the Gen 3 configured for either left or right mount. As a reminder, left mount means the unit is mounted on the left side of the vessel.
For back mount applications, we recommend using a left mount because of the latch location.
The Gen 3 Liquid Level Controller can be configured as either direct acting or indirect acting. The Throttle and Snap can also be adjusted.
The pilot lever should be mounted on either the left or right side depending on the operation—whether it will be operating in snap or throttle mode and whether it’s going to be direct or indirect acting.
Use the table to determine which side of the unit the Pilot Lever should be on. This information is also available on the inside cover of the unit.
As an example, if the desired mode is Throttle and Direct Acting, you would want to mount the pilot lever on the same side as the spring.
Change the location of the pilot lever as needed by simply removing the screw and moving the pilot lever to the other side.
The sensitivity knob should be oriented so that it is facing outward toward the operator.
Ensure that the protrusion is facing up, so it contacts the pilot actuator pin.
The displacer can be assembled in either vertical or horizontal orientation.
To install vertically, apply thread locker to the male threads on the displacer arm, and simply attach the displacer assembly to the displacer arm.
For horizontal orientation, remove the rod assembly from the displacer, apply thread locker to the male threads on the arm and connect the displacer directly onto it.
Before beginning installation, make sure all pressure is released from the vessel and confirm there is no pressure in supply gas or instrument air lines.
For NPT Connections, apply thread tape or sealant to the threads of the mount. Tighten sufficiently to seal the threads using a wrench on the flats of the mounting piece.
Do not use a wrench on the enclosure to tighten the connection.
Orient the enclosure vertically with the pilot on top when finished.
Remove all plastic plugs from the ports before beginning. All the following connections and gauges must be sealed with thread tape or sealant before installation.
Now you are ready to turn on the supply gas and calibrate the unit.
Calibrate the set point with no liquid on the displacer.
For a fail closed (FC) Valve: With the output at 0 PSI, turn the set point adjustment knob counterclockwise to produce about 10 PSI. Then turn clockwise and stop once the output reaches 0 PSI.
For a fail open (FO) Valve: With the output at 0 PSI, turn the set point adjustment knob clockwise until full output pressure is produced.
For a fail closed (FC) valve: With the output at 0 PSI, turn the set point adjustment knob counterclockwise to “snap on”, producing the full output pressure. Then turn the knob clockwise and stop once the output pressure reaches 0 PSI.
For a fail open (FO) valve: At full output pressure, turn the adjustment knob counterclockwise to “snap off” where the output pressure drops to 0. Then turn the knob clockwise until full output pressure is reached.
To speak with an expert about your liquid level control challenges, contact your local Kimray store or authorized distributor.
Today I'm going to walk through float-operated controllers, including both the Gen 3 Liquid Level Controller and the pneumatic level switch, focusing on how they work and where they're used.
First, let's look at where you might see a Gen 3 or Level Switch in action.
Producers use a Gen 3 Level Controller in any liquid accumulating vessel, including separators, heater treaters, and various separation equipment where they want to control the liquid level inside the vessel.
In gas production units, for example, Gen 3 level controllers are used for operating high pressure control valves, acting as dump valves, and for low-level shutdowns.
In a heated vessel, the level switch is crucial for preventing damage to the burner by ensuring it remains covered with liquid. On the other side of a gas production unit is a vessel that heats a coil of tubing to preheat the flow stream before it takes a pressure cut. If the liquid level drops below the burner tube it can cause damage to the burner, so you want to make sure the burner tube is completely covered with liquid, and that's the job of the pneumatic level switch in this application.
If liquid level drops below where that level switch is installed, it will shut down supply to the burner and the rest of the controls, shutting down the piece of equipment.
Another example of the Gen 3 and Level Switch being used is on a three-phase separator. Both the oil and the water dump valves are being operated by the Gen 3. The oil is on the top, and the water below. The displacer is sinking through the oil and only operating in the water. The oil is top level control, so it's only sensing the oil level inside of the vessel.
The level switch in this application is being used as a high-level shutdown. If it failed for any reason and liquid level began to rise in the vessel, instead of that liquid going out of the top of the vessel with the gas, once it hit that level switch it would shut down the controls or the inlet to the vessel. High- and low-liquid level shutdowns are common application for the level switch.
The output of the Gen 3 level controller can go to any control valve that requires 30 PSI signal to operate. That could be our high pressure control valves, it could be our low pressure control valves, or anything in between, just as long as it takes a pneumatic signal to actuate the valve 30 PSI up to 45 PSI. If you're using Kimray product, 30 PSI is all you need to supply the level controller to operate the dump valve.
With standard displacers, the Gen 3 can operate in both water and oil applications. It's important to keep in mind that in interface level control, where you have oil on top of water and you're trying to control the water level, the specific gravity differential between the water and oil has to be at a minimum of 0.2.
So if your water is fresh water and it has a specific gravity of 1, that means your oil needs to be at least 0.8 or lighter with the standard displacer.
We also have 2"x20" and 3"x12" displacers, which give more surface area and more displacement. Those both have a minimum specific gravity differential of 0.1. If your oil is really close to the gravity of your water, we suggest using those larger displacers to control interface level. If you're using the Gen 3 in a 2” connection, just be aware that the 3"x12" displacer won't fit through that.
The 2"x20" displacer is for a vessel that has a narrow internal diameter. If it's in the vertical orientation, make sure it will drop down properly and not hit that back wall.
These controllers can be set up for snap or throttle action. Most dump valve applications are going to be snap acting. Especially if you have an erosive stream, you don't want to use a throttling controller because that will keep the dump valve cracked open for longer periods of time, which just leads to erosion a lot faster than if you have a snap-acting controller that opens the valve fully and then closes the valve.
Another application where you would use a snap-acting controller would be if you're metering your fluids, so you want there to be a liquid-packed line. You don't want liquids trickling through the meter, especially with turbine meters or other meters that measure the velocity of that fluid.
A lot of producers use throttling for oil and for water if it's not erosive. You can choose which one you want to operate in, and it doesn't require any extra parts on the Gen 3. All it requires is that you change the position of the supply and vent on the level controller.
With left-hand and right-hand mount options available, along with specified operating parameters, users can customize installations based on their needs and environmental conditions.
Our standard displacer has an operating temperature of 175° F. If you are putting it in an application that's going to experience higher temperatures than that, use the stainless steel displacer; however, you go from 4,000 PSI working pressure down to 1,500 PSI.
The stainless steel displacer is hollow, so it's actually more like the floats on our level switches, and that lowers the operating pressure to 1,500 lbs. Do not go over that operating pressure or it could crush the displacer.
We have a 2” NPT connection on all of our Gen 3 models. If you are needing a flange connection, it's as easy as adding an adapter.
As you're operating the Gen 3, you might have buildup of either paraffin or sand or other solids inside the neck of the controller. With previous versions of our level controller you have to blow down the vessel and take the unit completely out of service to clean that out. A good feature of this one is you can access that through the paraffin clean out port.
You still have to depressurize your system, but this allows you access to the inside where the stem is, and clean out any solid buildup inside the Gen 3. Then you can pressurize your vessel again and not have to take the Gen 3 completely out of service, saving time and money.
There's a 40 micron filter on the inlet side, so when you supply this with gas or air, it's scrubbing any solids out of the supply gas or air before it gets to the pilot inside of the level controller. One of the benefits of the Gen 3 is that it does not vent inside of the housing, so no gas will be building up inside.
The vent port is ¼” NPT connection, so you can capture that vented gas if you are are wanting to direct that to a vent capture system like a VRU or another low pressure gas gathering system. You can make this emissions free by capturing that gas or supplying it with compressed air instead of natural gas so that way when it vents it's just venting air and not gas.
When you're determining whether you want this to be snap or throttle acting, there are options for which ports to use. "S" is for SNAP and "T" is for THROTTLE.
Vent is always going to be the opposite of your supply, so if you make this a snap controller, then it's going to vent out of one of the top ports. You can plug one port and just have it vent out one.
The output of the level controller will always remain the same. That will be going to the dump valve and will always remain the same whether you're in snap or throttle mode.
Every Gen 3 comes with an Allen wrench to help you make the adjustments, switch from snap to throttle, or change the action of the Gen 3. You can also remove the lid to make it easier to access the inside.
There are two adjustment points on the Gen 3—the sensitivity adjustment and the level, or you can think of it as like top level adjustment. This is going to adjust your span, or the amount of travel that the displacer has inside of the vessel, and then this one is going to adjust the top level, or where your controlling that level.
Let's say you have the sensitivity adjusted to control 8” of liquid. From the time that it opens and empties that liquid to the time it closes, you're controlling 8”. Adjustment the indicator on the pilot lever left or right will either widen or narrow that span.
No, let's say you're controlling 8” of span, but you just need that span to be lower or higher in the vessel. The Set Point Adjustment Knob is where you'll make this adjustment as you turn that clockwise and counterclockwise. (These instructions are noted in the instructions on the inside of the lid.)
Use the Allen key in the hole on the adjustment knob to give you a handy spot to make adjustments. There are also flats on this that you can put a wrench on and turn to make adjustments that way.
If you have this in throttling mode, it's suggested that you start your sensitivity on the middle hash mark. Then make fine adjustments from there. If you change too much all at once you may not know where you went wrong.
If you have this in snap mode, we suggest starting all the way in. That way you have the least amount of sensitivity. Then make small incremental adjustments to get where you want to.
We have a chart that notes where the position of the internals to the Gen 3 level controller need to be. It depends also on the failure position of your dump valve.
The pneumatic level switch, is a simple, on/off switch ideal for applications requiring high- or low-level shutdown. The Gen 3 controls a span of liquid that's adjustable while the level switch is either on or off.
The total travel is just under an inch, so you would use this in applications for high or low level shut down, and you can also use this in applications where you're limited on space, for instance if you don't have a very large diameter vessel.
Our external float cage can be used to position the level switch wherever you want external of the vessel. So let's say you're using a Gen 3 level controller, but you wanted it to change the position of the liquid level that's controlled inside the vessel, you could use an external float cage and position that at whatever level you want it to control outside of the vessel.
You can also use two external float cages of them to achieve a liquid gap control. In this set up there are two separate level switches working in tandem, and the liquid level oscillates between those two level switches. There's a relay that you have to use in between the two switches to get that to operate correctly, but just like the Gen 3 controller you only need 30 PSI of supply gas or air to operate the level switch.
The level switch has a 2,000 PSI working pressure. Because of the stainless steel, you can get up above 180 degrees in temperature of your fluid and not harm the the displacer or the float.
Another feature of the level switch is that it has a manual override, which can be used to test the function of the level switch without there having to be a change in liquid level inside of the vessel. You simply push down on the manual override and it manually actuates the float inside.
This allows you to check your dump valve to make sure it's operating correctly and you're getting supply gas or air through the whole system.
The vent on this is a quarter inch connection, so you can capture that vented gas into a low pressure gas gathering system.
Float Operated Controllers Learning Path
Installation, Repairs & Conversions
