FW Tank 2/3 full without filling it

[War]

I have had a Jay Feather RBM 23 for about a year now and only did city water hookup. Haven’t even used the pump at all. I was going to sanitize the FW tank and noticed it was already 2/3 full. How can this be?

[RetiredLEO]

Probably a bad electronic tank monitor. One of the most common problems. I would check it to see if it's accurate or that it's "fibbing" to you. Will find you a link to a much better monitoring system.

[RetiredLEO]

If the tank really was 2/3 full somebody will be along to help you.
If the monitor was lying to you here is a good solution.
When I order a new TT if the factory isn't using these it will have a "switch-out" before it leaves the lot.
https://www.garnetinstruments.com/rv-shop/

[ALJO]

It is a possibility that your pump valves are passing the water through back to the tank.
If you are sure you didn't fill it that's the most likely cause. Just check by the pump and set it on the valves on antifreeze suction line, if it slowly fills, then you got the answer.

[JHerzog]

Originally Posted by War

I have had a Jay Feather RBM 23 for about a year now and only did city water hookup. Haven’t even used the pump at all. I was going to sanitize the FW tank and noticed it was already 2/3 full. How can this be?

Find a place to open your fresh water drain and see if that much water starts coming out. If it runs for a while it is most likely accurate. If nothing comes out its a bad sensor. The dealer may have filled it so you could test it on your walk through and its been full ever sense

[bigironcoder]

I've had this happen a couple times. The pump's internal check valve was allowing water to back flow into the fresh water tank. If you take it to a dealer, they will most likely sell you a new pump. However, you can take the pump head apart and clean the check valve yourself. The times it's happened to me, there was a little sand/debri keeping the check valve from fully seating.

You can also add a separate check valve in the water line. That way you won't have to take the pump apart to clean its internal check valve.

[Racinforthefinish]

Same thing happened to me on my 23 rb. I was hooked up to city water for five days and when I got ready to leave the fresh water said full, the gauges are hardly ever right so I ignored it and went down the road. One of my tanks fell out almost to the ground. A tech explained that the water pump back flow valve failed and filled the tanks. Live and learn!