Water tank sensor

[kevinB24]

Can a water tank sensor go bad? I leveled my rv then filled my water tank at the house and once it came out the overflow drain I closed the valve and stopped filling. My sensor reads 2/3 full but if it is coming out the overflow I assume it's full. Is that a fair assumption?

Also when I got to camp (boondocking) I opened the valve and it drained for 10 minutes. Is that a problem? Sensor still reading 2/3 full, but it seems like a lot of water came out.

[Ballistic]

It could be the sensor/probe has debris caked onto it or the resistor pack has failed. Worse case it’s both, but I’d bet it’s debris on the top sensor. Resistor packs are ~$5 if that is the source of failure.

[ccob28]

I find that the common sensors that are installed in most RVs work for awhile and over time become useless. They do cake up with debris and give false readings. I have replaced them with new resistor packs and overtime (within a year) get the same results. So I investigated an alterative and bought a new system called SeaLevel and had it for two years with success with each reading. Its a bit pricey but totally worth it and easy to install. There are many YouTube videos on how to install it. I hope this helps.

[GolfingDave]

Originally Posted by kevinB24

Can a water tank sensor go bad? I leveled my rv then filled my water tank at the house and once it came out the overflow drain I closed the valve and stopped filling. My sensor reads 2/3 full but if it is coming out the overflow I assume it's full. Is that a fair assumption?

Also when I got to camp (boondocking) I opened the valve and it drained for 10 minutes. Is that a problem? Sensor still reading 2/3 full, but it seems like a lot of water came out.

Depends on how fast you were filling it and how tight the fit was at the fill opening. Got to let air out while filling. I fill mine via a flow meter and slowly. I can get water coming out at half full if filling too fast. Find your tank size and fill with a flow meter. You will know for sure then.

Second paragraph is not clear. Drain it after camping to empty for the trip home? If so something is amiss if still reading 2/3.

I don't trust any of my sensor readings, especially the black. I have a good idea of how much water I use on a daily basis and how fast the black tank will fill up. I put in as much as what I will be needing via the flow meter when I will not be hooked up to water. No sense putting in 50 gallons when I know 30 will do for the time I need it.

Even though I do not trust the sensors it appears I have about 10 gallons of water left at the 1/3 reading on the fresh tank.

[kevinB24]

Originally Posted by Ballistic

It could be the sensor/probe has debris caked onto it or the resistor pack has failed. Worse case it’s both, but I’d bet it’s debris on the top sensor. Resistor packs are ~$5 if that is the source of failure.

How would I go about cleaning the sensors on the water tank?

[kevinB24]

Originally Posted by GolfingDave

Depends on how fast you were filling it and how tight the fit was at the fill opening. Got to let air out while filling. I fill mine via a flow meter and slowly. I can get water coming out at half full if filling too fast. Find your tank size and fill with a flow meter. You will know for sure then.

Second paragraph is not clear. Drain it after camping to empty for the trip home? If so something is amiss if still reading 2/3.

I don't trust any of my sensor readings, especially the black. I have a good idea of how much water I use on a daily basis and how fast the black tank will fill up. I put in as much as what I will be needing via the flow meter when I will not be hooked up to water. No sense putting in 50 gallons when I know 30 will do for the time I need it.

Even though I do not trust the sensors it appears I have about 10 gallons of water left at the 1/3 reading on the fresh tank.

I have a valve on my water tank over flow hose because when I tow water has come out, so I put a valve on it. When I got to the campsite i leveled up Nd I open the valve to run the water tank. What seemed like lots of water came out the overflow drain. Tank still reading 2/3 full..

[Daxinarian]

Originally Posted by kevinB24

Also when I got to camp (boondocking) I opened the valve and it drained for 10 minutes. Is that a problem? Sensor still reading 2/3 full, but it seems like a lot of water came out.

There are many posts that discuss excessive water coming out of the overflow. There is no definitive answer as to why it occurs, though I tend to believe it has to do with a siphon created by the overflow tube.

[Ballistic]

Originally Posted by kevinB24

How would I go about cleaning the sensors on the water tank?

Loosen the inner most nut and the sensor can be removed from the tank. Inspect, clean and reinstall. With that said, pending the quality of the water I doubt the sensor is fouled with debris given it's you 'water' tank, however, there is some nasty hard water out there.

My bet is still on the resistor pack.