S5U Tank Level Sensor, 1-1/2NPT - 39"

Wema's most versatile senders are the SSS/SSL, S3U/S3, and S5U/S5 models. These single stainless steel senders typically have an NBR (Nitrile Butadiene Rubber) float, and differ only in their mounting methods.
• SSS/SSL senders have a basic SAE 5-hole pattern, and typically mount with a gasket and screws
• S3U/S3 senders have a 1.25" BSP threaded mount, and come in models for American (S3U) and Euro (S3) dashboard gauges
• S5U/S5 senders have a 1.5" NPT threaded mount, and come in models for American (S5U) and Euro (S5) dashboard gauges
All these stainless steel models can be used with water, gasoline, hydraulic oil, or diesel.

The 1-1/2" NPT threaded, S5U Liquid Level Senders in this entry have an American Standard Outputᵠ (33 ohms resistance when the tank is full).
They are only suitable for use with matching 30 ohm "American" style dashboard gauges.
Their length is measured in inches.

The S5U sensor has a float which rises and falls on the central shaft with the level of liquid in the tank.
The sensors are fully insulated to protect against dangerous electric currents inside the tank.
This extremely important safety feature protects against electrolytic corrosion, as well as the danger of an explosion when used with gasoline.

The mounting thread is 1-1/2" NPT, tapered male National Pipe Thread.
Retro-fit/replacement installations of these senders will generally use the existing tank mount.

For new installations, a user supplied 1-1/2" female NPT fitting will need to be mounted on the tank.

The sending unit length is measured from the bottom tip of the sender to the flange at the top of the threads.
The sender you select should be at least 1" less than the depth of a plastic tank, and 3/4" less than the depth of a metal tank.
Note: if the top of your metal tank flexes, deduct one (1) inch from the depth (like a plastic tank).

• For use with diesel, gasoline or water
• Available in Imperial measurements in 1" increments from 4" to 60". (Metric lengths available from 500mm to 1050mm – see S3 BSP Threaded Senders.)
• Sensor electrical resisitance range is 240 Ohms (empty tank) through 33 Ohms (full tank) (Standard Aftermarket)
• Can be used with any Wema System Dash Gauge with the same resistance (Ohm rating)
• Simple, reliable and accurate reed-switch/magnetic field design. The float is the only moving part, minimizing potential mechanical failures
• All 316 stainless steel
• Includes 38mm and 43mm O-rings for sealing
• Operating Voltage: 12/24V DC
• NBR mounting gasket (1Pc) and screw (5Pcs) included
• Custom lengths can be special ordered


American Standard Outputᵠ
Standard American gauges and senders are designed to work with a variable resistance from 240 ohms empty to 33 ohms full, while European products are designed to work with a variable resistance from 0 ohms empty to 180 ohms full.
Senders and the dashboard gauges they are paired with must have the same resistance range.
The American Standard Output is non-linear and is based on American Boat and Yacht Council standards with plus or minus 5% tolerance for range difference.
Resistance readings at different levels are as follows:
• 33 ohms at 100% 
• 67.5 ohms at 75%
• 105 ohms at 50% 
• 142.5 ohms at 25% 
• 240 ohms at 0%


* Note – Fastener torque setting for mounting (with O-rings) to metal tanks is 9 +/- 1 Nm; plastic tanks is 7 +/- 1Nm