Author: Boat Accessories Australia Date Posted: 24 August 2022
To get started, take a look at your current sender and see if there is information stamped on the top. If your sender has the following information, then you can easily locate the replacement you will need.
[Please note: the code 001300 refers to the S3 head and the code 001306 / 001305 refers to the S5 sender head]
If your current sender doesn’t have this information stamped on the top or you don’t have access to this, then you will need to answer the following four questions:
There are two styles of fittings available:
The S3 has a screw-in head with a 1 1/4" BSP thread NOTE: BSP (British Standard Pipe) measurements refers to the internal bore of a pipe, not the outside of the thread |
The S5 has a bolt-down head with 5 holes (standard SAE-5-hole pattern). |
For tanks with an existing 6 hole pattern, you will require the Topside/Underside 6 hole Flange Adapter with 1-1/4 Inch BSP which will enable you to attach a S3 screw-in sender.
The sender and gauge must have the same resistance values or the gauge will read incorrectly.
The two resistance values are:
If your gauge is reading empty when full and visa-versa, then its possible you have purchased the incorrect resistance sender to match your gauge.
You can either test the gauge or the sender to find this out.
If you have access to the wires on the back of the gauge;
If you don't have access to the back of the gauge;
Sender length is measured from the underside of the flange to the base of the shaft.
To measure an S3 sender (with screw-in head) measure from the top of the thread to the bottom of the stem. |
To measure an S5 sender (with bolt-down head) measure from the underside of the flange to the bottom of the stem. |
Note: You can usually fit the maximum length of sender for the total depth of your tank. However, we recommend leaving at least 25-50mm from the bottom so your tank will still have some liquid remaining when reading empty. For example: if your tank depth is 250mm, then we recommend opting for a 225mm long sender.
We currently stock lengths available from 150mm to 1000mm. Longer lengths are available upon request.
If your S5 or S3 sender has 2 wires then it is a standard resistance sender which we can supply.
If your S5 or S3 sender has 3 or 4 wires then it is either a 0-5V, 0-10V sender or it has a high/low level alarm. We do not supply these types of senders.
Our Wema Tank Level Senders are grouped as per mount type and OHM’s reading, please see links below:
WEMA Fuel sender
By: John Hurt on 24 December 2023My current sender is a WEMA UFW-6.5, W16 200. It is 6.5 inches from the bottom of the flange to the end of the stem. I try to ohm it and it reads open on my fluke meter for resistance. I assume it is American and not european, it has two wires and 5 screw holes on the flange. I have no idea about the Ohm range I need. The old one I have is made of plastic. It is on a 2002 Seapro 170CC boat fuel tank. So which one do you recommend for a replacement?
Boat Accessories Australia Response
Hi John,
Thank you for your question on our blog “How to Identify which Wema Tank Level Sender you need”
If you don’t know what OHMs reading it is but believe it is American, then they are usually the 240-30 OHMs. You can also check your gauge (they sometimes have OHMS stamped on them) as the gauge needs to match the sender to work correctly.
The 5 hole flange is the S5 series which can be found on our website here: Wema Tank Level Senders S5 240-30 Ohm
6.5 inches length = 165mm. We stock 150mm length or 175mm length. I didn’t think WEMA made a sized in between so maybe just double check the length you need, or measure your tank to see which will best fit with at least 5cm at the bottom.
If you purchase the 240-30 Ohms, I highly recommend testing it with your gauge first before installing to ensure you have the right reading. We accept returns on items that are still in their original condition within 30days, so you can always just send it back and purchase the correct one.
Hope this helps, if you have any other questions, please let me know.
Thanks, Alison
BAA Customer Service
Faulty Sender
By: Phillip on 7 September 2023Hi there.
My sender is labelled 0-10v and not ohms.
When the tank is full the gauge reads 64%
How do I test if sender is faulty?
Boat Accessories Australia Response
Hi Phillip,
Thank you for your comment, the “0-10v” is probably the voltage, so you will need to get a multimeter to read what OHM’s it is and check where the fault is.
Please see dot point 2. What resistance (OHMs) is it? within this blog post to read through how to run your tests.
If you are still having issues, we recommend speaking with a marine electrician who can do more test and provide more knowledge on this.
If you have any questions, please let me know.
Thanks,
Alison
Need a new sender
By: Douglas graham on 26 July 2023I have a wema s5 6 inch and the resistance reads 26 ohms At full and 194 ohms empty. There's a dead spot in the center were the ohm reading won't change . Do you sell this?
Boat Accessories Australia Response
Hi Douglas,
It sounds like one of the diodes has gone, so yes you will need a replacement:
Wema Tank Level Sender S5 0-190 Ohms 150mm
SKU: 1100104
You can order this directly online by searching the SKU number, or give us a call.
Thanks, Alison