The Ultimate Guide to Float Level Sensors Electrical Connection Electrical Connection Fitting with threadsA HIGHER down LEVEL OF SATISFACTION Threads up L3 Float L2 Float Stop L1 OAL Electrical Connection Electrical Connection Fitting with threads down Threads up L1 OAL Float Float Stop Table of Contents Introduction .................................................................................................................................................. 5 Overview of level sensors, their use and selection ............................................................................. 6 The float switch level sensor ................................................................................................................. 7 The continuous level sensor .................................................................................................................. 7 Magnetic float switch reliability ............................................................................................................ 7 Examples of level sensor use and applications ....................................................................................... 8 Oil/water separators ............................................................................................................................... 8 Food processing equipment .................................................................................................................. 8 Biotech..................................................................................................................................................... 8 Chemical processing and storage ......................................................................................................... 9 Commercial washers .............................................................................................................................. 9 Container level indication ...................................................................................................................... 9 Fuel management ................................................................................................................................... 9 Electroplating .......................................................................................................................................... 9 Fluid power ............................................................................................................................................. 9 Food and dairy ........................................................................................................................................ 9 Freon recovery ...................................................................................................................................... 10 Humidifiers and dehumidifiers ............................................................................................................ 10 Lubrication equipment ......................................................................................................................... 10 Marine applications .............................................................................................................................. 10 Miscellaneous ....................................................................................................................................... 10 Off-highway vehicles ............................................................................................................................ 10 Industrial parts washers ....................................................................................................................... 11 Power generation ................................................................................................................................. 11 Restaurant equipment .......................................................................................................................... 11 Semiconductor equipment .................................................................................................................. 11 Solvent recovery................................................................................................................................... 11 Waste oil and grease recovery ............................................................................................................ 11 Water treatment equipment ................................................................................................................ 11 Diesel fuel/oil tank and transfer systems ............................................................................................ 12 Medical equipment ............................................................................................................................... 12 Heating, ventilation and air conditioning ........................................................................................... 12 Heavy construction equipment ........................................................................................................... 12 2 fpisensors.com The Ultimate Guide to Float Level Sensors How to select custom liquid level float sensors ..................................................................................... 12 What is the desired operation? ........................................................................................................... 12 What fluid type will you be measuring? ............................................................................................. 13 Typical float switch materials ..............................................................................................................13 What is the environment like inside and outside of the tank? .......................................................... 14 What is your electrical load? ............................................................................................................... 15 How will the sensor be mounted? ...................................................................................................... 16 Are there tank restrictions? .................................................................................................................. 17 Design details and Options .................................................................................................................. 17 Pipe centering disc ............................................................................................................................... 19 In summary… ....................................................................................................................................... 20 Float switch and level sensor selection checklist .................................................................................. 21 Liquid parameters ................................................................................................................................ 21 Electrical requirements ........................................................................................................................ 22 Mechanical component selection .................................................................................................. 22-23 Liquid level float switch installation guide ............................................................................................. 24 Basic instructions ................................................................................................................................. 24 Installation quick check items .............................................................................................................. 26 4 20 mA continuous level float sensors .............................................................................................. 26 0-5VDC continuous level float sensors ............................................................................................... 27 Maintaining a float style level switch ...................................................................................................... 28 Inspections ............................................................................................................................................ 28 Troubleshooting a float style level switch .............................................................................................. 29 Float is not positioned properly or moving properly ........................................................................ 29 Shock or damage to the floats or the sensor assembly (bent, dented, etc.) ................................... 29 Excessive moisture around the wires exiting the sensor or connections ....................................... 29 Reed switch failure ............................................................................................................................... 30 Float’s specific gravity does not match the liquid that is being measured ..................................... 30 Wire colors do not match the level switch ......................................................................................... 30 Troubleshooting a float style 4-20mA continuous level sensor ........................................................... 30 Troubleshooting a float-style 0-5VDC continuous level sensor ........................................................... 31 Procedure for reversing a float to change the Normal Switch State ...................................................