Fresh Water Sensor Problem

[ehackney]

I winterized my travel trailer last fall and left the tanks empty. The fresh water tank now reads 1/3 full (don't remember checking it when I winterized). I'm early in checking out this problem, but tapping on the tank, it sounds empty. I know that grey and black tank sensors get gunked up, but what would cause a problem with a fresh water tank sensor?

Thanks in advance,

Hack
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[ehackney]

I winterized my travel trailer last fall and left the tanks empty. The fresh water tank now reads 1/3 full (don't remember checking it when I winterized). I'm early in checking out this problem, but tapping on the tank, it sounds empty. I know that grey and black tank sensors get gunked up, but what would cause a problem with a fresh water tank sensor?

Thanks in advance,

Hack
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[Ron Schulz]

Did you open the drain valve to verify it is indeed empty? The sensor may have a bad ground connection.......

[ehackney]

I have not opened the valve to verify it is empty, though I did do that when I winterized. I keep it in a storage area and have not been able to get back there yet.

Where is the tank sensor, BTW? I guess on top makes sense, but that makes it hard to get to. If I can get to it, I can check the ground.

Thanks for the reply.

Hack
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[Hitchhiker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Where is the tank sensor, </div></BLOCKQUOTE>

Most tanks will have three sensors located on the sides of the tank. One each at 1/3 level, 2/3 level, and at full. If yours is reading 1/3 when empty you might check the connection to that sensor.

These sensors can get corroded or oxidized and cause screwy readings. If the connections and grounding checks out, try some of the sensor cleaner stuff from Camping World, maybe that'll get it reading right again.

[Ray,IN]

Hey Richard, can you use sensor cleaner in the drinking water tank? I've got the same problem.

[Hitchhiker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">can you use sensor cleaner in the drinking water tank? </div></BLOCKQUOTE>

Ray,

Well, I posted to Hack's thread suggesting he use sensor cleaner, however now that you've asked the question, I'm not entirely sure I was right to have said that for a fresh water tank. I might need to read the label first but I don't have any to read it from.

At the very least, the tank should be sanitized with beach afterward. Then remove the bleach taste and smell with some baking soda.

Good question, maybe it'll stimulate some other comments from folks who've tried it.

[ehackney]

Yes, the tank was empty and reading 1/3. I added enough water to get it to read 2/3, so I suspect the connection on the lower tank sensor. The fresh water tank is inside a cover, so it will be a real pain to get to the sensor connections.

The background is that I have sold this trailer. It was ehen I was checking it out with the (then potential) buyer that I first noticed the 1/3 reading while empty. I guess it's his problem now, but I felt bad about it and would have checked it out further and tried to remedy it if I would have had the time.

Thanks for the responses, everybody.

Hack
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[Ray,IN]

I've been thinking about this erroneous sensor reading. Yea, I know, it's dangerous at my age. I suspect humidity inside the tank is causing this problem. A small quantity of water remains in the tank after draining due to the construction of the drain opening. This causes water vapor to condense on the interior of the tank in changing temperatures. causing a false sensor response. That's my theory and I"m sticking to it until someone comes up with a better one.

[cwsoules]

Sometimes when I hold the sensor button down the top reading sensor light will go out. I use my sensors to get some idea of where we are in using the tank, but I do not spend alot of time trying to "fix" them. Some times after a extended flush of the black tank the sensors will seem to work properly, but within days of use it will act incorrectly. We have learned that we can stay between a week to two weeks before the black tank will be nearly full. The shower grey tank works the same way, and the kitchen tank can fill first if we are eating all meals in the rig.

My recommendation is to largely ignore these sensors and go fishing or do something else which is more likely to yield long lasting results.

[RustyJC]

Yep, we can send men to the moon, but at the price point the manufacturers (and ultimately the consumers, I suppose) are willing to pay, we can't reliably measure liquid level in a tank.

Rusty

[gmachine]

http://www.snake-river.org/

[electric6]

Hitchhiker and Ray are right-on. The contacts in the tank are normally brass and the condensation will start to oxidize them and any current passing between them will cause a false reading. Adding fresh water will sometimes knock off some of the corrosion and clear up the false reading temporarily. Suffering from this problem myself I always thought it was a mistake draining the tank and leaving the exposed contacts to the air instead of filling the tank with a mixture of water and antifreeze during storage.

[Jeff_in_The_Dalles]

I have the same issue. I taked to the local RV shop guy, who I trust, who related that the sensor is likely spin-welded into the tank.

He felt that a person could put another sensor along side the old one, or you could try some of the sensor cleaner- but that his experience with sensor cleaner additives is that results, if any, would likely be temporary.

In short, he convinced me that it isn't worth messing with...