Centroid Products
2104 HIBISCUS DR.  -    EDGEWATER, FL   32141
TEL: 386-423-3574   -   FAX:  386-423-3709


Electronic Sending Units For Fuel, Oil, and Potable Water

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The ELECTRONIC SENDING UNIT for FUEL, OIL, and POTABLE WATER tanks provides a continuous readout of the liquid level in your tank. The unit (which has no moving parts) consists of a sensor probe and an amplifier. The amplifier components, which are located in the mounting plate assembly, are encapsulated in an epoxy resin compound to seal out moisture and other contaminants which could affect the operation. The mounting plate assembly has the same 5 hole SAE bolt pattern mounting dimensions as the standard float sending units they replace. The meter (receiving unit) can be remotely located close by or in your dash.

Electronic Sending Units
FUEL SENSOR PROBE (Gasoline or Diesel) - The probe is constructed of concentric tubing (a small brass or alum. tube inside a larger aluminum tube). The tubes, which are separated by small insulators to keep the tubes from touching, acts as a capacitor that has one value in air (empty tank) and changes in value as the fuel level rises inside the probe. The amplifier converts these values to a signal suitable to drive a standard meter or other display device.

WATER SENSOR PROBE - The probe consists of a PVC tube with a bare stainless steel (ground) wire running along the outside and an insulated (sensor) wire through its center. The PVC tube is to hold the wires in place. The output to the meter changes as the water level rises on the sensor wire.

The probes come in 12 inch increments and can be cut to any length down to the next lower increment.  We prefer to build them your required size, however, for which there is no extra charge.  It saves you from having to shorten and recalibrate the sender.


Even if the sensor did corrode (which is improbable because of the high quality materials used), a thin layer of corrosion on the surface of the sensing elements would not change the accuracy because the gap over which the capacitor works is almost 1/10 of an inch whereas corrosion would be measured in 1/100’s.


A Capacitive sensor is capable of detecting water in the fuel tank. The presence of water, which will ruin a diesel engine, is readily shown by an overfull indication on the meter. If fuel were being pumped into your tank from a supplier who had water in his big tanks, the presence of the water would show up immediately on your gauge by giving a overfull indication even though the tanks were only 1/4 full. This does not damage the sensor and once the water is pumped out, everything would be normal again.

Electronics have been designed to minimize meter error caused by variation of battery voltage.

Eliminates excessive needle bounce on the meter while underway.

Can be built to fit tanks from 3 inches to 120 inches deep.

Works with most receiver units (meters).

NOTE: some VDO meters work backwards from standard meters. Please indicate if yours is this type when ordering. If you are not sure of the type you have, give us the model number when ordering please.



CENTROID PRODUCTS has a two year guarantee against failure of any electronic component in the sending unit. Simply return the defective unit to the factory and we will either repair or replace if free of charge during the warranty period.

Centroid Products, Inc.

2104 HIBISCUS DR.  EDGEWATER, FL 32141        -         TEL : 386-423-3574  FAX : 386-423-3709