WEMA Tank Sensors

[Journeyman]

Hi folks, Now that I have two new water tanks going in, I am thinking of specifying WEMA sensors for them. My new fuel tank has one. And I am thinking of adding one to my holding tank. The idea is to route all the electrical leads to a single WEMA master monitoring display. I notice that the holding tank sensor is of a considerably different design that the fuel and water sensors. And my fuel/water tank builder was less than enthousiastic about this sensor. Any opinons about tank monitoring and WEMA gear in general?

[rourkeh]

Blue seas systems make a host of electrical panels etc. But one of the cool things they make is a VSM digital display that fits into my electrical panel and ultra sonic tank sensors ($75) each that I put on 4 of my tanks. The VSM also displays all the electrical functions as well.
Vessel Systems Monitor VSM 422 - PN 1800 - Blue Sea Systems
These guys make top notch equipment.

[speciald@ocens.]

My WEMAs tend to stick in the water and holding tanks.

[CSY Man]

I have 4 WEMA sensors/gauges:

Water tank, fuel tank, nav light indicator and water temp.

Perfect reliability and perfect performance.

[beetle]

I installed the WEMA sensors on 6 tanks on board (3 fuel, 3 water) and didn't bother with putting a sensor in the holding tank as it's simple enough to look at the holding tank to see it's fill level.

The sensors seem to be bomb-proof, are simple to install provided you have clearance above the tank to drill the hole and install the sensor.

Accuracy is so-so, certainly good enough to distinguish tank volume in roughly 1/8 tank capacity increments. The issue seems (to me) that the collar that floats up and down on the vertical metal sensor rod sticks somewhat to the rod such that I'll be filling a tank and then the gauge will suddenly hop up abruptly - so I'm careful to avoid overfilling when attempting to fill a fuel tank completely, for example.

I do like the single display that can be switched to indicate for all the different tanks - much better than having a dedicated gauge for each tank. This does mean you have to calibrate the gauge the gauge for each tank - half full in tank 2 might mean I have 18 gallons, and in tank 1 there might be 21 gallons. I made up a little drawing of the gauge for each tank, and if I really want to know what's in a particular tank then I switch to that tank, tap the display gauge, and refer to my drawing of that gauge for that tank.

- rob/beetle

[beetle]

Originally Posted by rourkeh

ultra sonic tank sensors ($75) each that I put on 4 of my tanks

How did you get the VSM 422 to monitor 4 tanks? I thought it had the capacity to manage 3 tanks.

And Blue Sea Systems is good stuff. I have more than three tanks to monitor, so the 422 didn't fit the bill.

[gulfstar37]

We installed two Wema sensers monitored by one guage. One is for water the other, diesel tank. The fuel tank had baffles and did not allow room for a swing arm of others like Tempo sender. Really have not had any trouble with them but as mentioned previously they will stick a little when fueling then jump up. As far as when in sailing or motoring, this does not seem to be an issue.

I looked at buying one for the holding tank but was not convinced there would not be a problem. I've heard of people installing a flush line on the senser to help keep the (gunk) out. I like the KISS system, so currently I dive under the cushion and shine a flash lite on the side of the fiberglass tank to see the level.

Note: WEMA was very responsive when I had a meter face crack. This was three years old. They replied it was still just under warrantee even though I think there is a one year written warrantee, and replaced the whole meter station no questions asked. No connection with them just good service.

[Microship]

I have three Wema sensors for my diesel tanks, and they each have a Maretron TLA100 to interface them to the N2K backbone. I configured a screen on the DSM250 to show all three levels at once (port and starboard 70-gal wing tanks on top, 90-gal aft tank below). It all works perfectly, but wasn't exactly cheap; I've been curious about the VSM and note with interest that it has a serial port (undocumented, last time I checked, but that might have changed by now).

Cheers,
Steve

[Chief Engineer]

I have installed a number of them and have ZERO problems with any of them.

[Ike]

Wema sensors are the most commonly used by boat manufacturers in the US. They are reliable and durable. The accuracy is dependent on the type of sensor. They make various kinds, from the older float on an arm type (not very accurate, to the newer inductive and capacitive types that are solid state and much more accurate.