Water tank gauge

[wwestman]

Our new to us boat has a water tank gauge on the lower helm. It lights up but the needle does not move. The top of the tank has a sending unit.

Knowing absolutely nothing about how these things work can someone give me some insight in how to go about checking the sending unit, the wiring and the gauge to see where the problem is. There is a sight tube on the side so I can see what level the tank is at but that requires lifting the master bed up and moving it aside, not real easy. I would rather have a working gauge.

Any ideas or suggestions?

Thanks

 

[koliver]

In about the same size boat, I have twin tanks under the bed in the aft cabin and twin tanks in the lazarette. The bottom level of the laz tanks are above the top of the bed tanks. They are interconnected, so the top tanks are empty before the bed tanks start being used.
On a long trip, we go through the 150 gals of laz tanks in a week or so, then, the level of the bed tanks stars going down, and the bed tells us, by oil-canning when the weight of a person arrives on the mattress. Also, by then the boot stripe, at the transom, rises by a few inches.
Those clues are really all we need, to go for a fill up.
When filling, all of the deck fills are on the lazarette deck, so the bed tanks get filled first, then the laz tanks. We always fill to overflowing, so know we have as much as we can carry.
When buying this boat, the broker showed off the sight tubes and valves that would allow use of each tank separately, but we have never seen a reason to use any of that. Nor have I found any reason to remove the useless sight tubes.

 

[ranger58sb]

Inside-tank senders often work on resistance; a float wanders up and down a tube (or sometimes they might be elbow-shaped arms) and resistance changes as tank level varies.


You can check for voltage on the two sender terminals to see if power is there... there might be a fuse in line, could be a simple fix. If voltage checks out, do a continuity test on the sender terminals to see if the thing is likely to working or not.


If the gauge happens to be a WEMA needle gauge... they have info about senders on their KUS (WEMA) website. Older WEMA senders were plastic, since replaced with stainless.


Changing a sender can be relatively trivial, assuming easy access. If it were a holding tank sender, it would be good to do lots of flush/rinse/repeat first...


-Chris

 

[caltexflanc]

If knowing exactly how much water an activity uses, and how much is left in your tanks, then once again I will pimp one of the absolutely very best upgrades we did to our boat.

The World's Best Potable Water Management System For Boats and Rv's | WaterCounter

We lived away from a dock for weeks at a time and that thing was tremendously useful in managing the water supply. We knew know much various lengths of shower took, or various cycles on the dishwasher or laundry washer, etc. And of course exactly what we had left.

 

[Stu-L]

Simple water Gauge

I have a 1981 34' Californian with 75 gal water tank with no gauge. I got a simple gauge from Home Depot that measures flow. It has water hose connectors. I put it on the output side of the pressure pump and it measures water flow when shower, sink and toilet water is used. When I fill the tank I just reset the meter. It cost me $12.00.

 

[Chrisjs]

I installed a mechanical water meter that measured flow from both water tanks just before a filter and the water pressure pump. Not as convenient as the "Watercounter" with its electronic sender but same principle. Just read when you fill, know your tank capacity and count up to know how much has been used. Certainly beat trying to read a sight tube on the lower tank under the forward berth!! I think it only cost about $75 and was calibrated for more accuracy than I even needed.