Fresh Water Tank Keeps Filling

Don't know about your Bighorn, but Grand Design did away with the Anderson valve in 2016 due to the high number of warranty complaints on just the exact issue you had in your rig. From what I've read, the Nautilus panel which GD replaced the Anderson with is much more robust. But the plumbing behind the panel is still very complicated.

The Andersen Valve on my bighorn went out on me when we were dry camping last week. It was bypassing between the pressure and tank side of the valve so the pump would try to fill the tank when I was in Normal mode. Had to run to a hardware store and get a couple fittings, caps, and chunk of line to bypass the valve so the pump pulled direct from the tank. On the plus side, even though I'm out of warranty now the customer support at Andersen was great and they sent me out a new cartridge to repair it with, no charge, with an assurance the new part is much more reliable and I didn't need to purchase a backup valve just in case. Can't speak to the reliability of the new part yet, but the company has very friendly and helpful folks that are ready and willing to make things right.

I am glad my Tango is simple with a separate city water c0nnection, fresh water fill and water heater by-pass.

Any one who has seen the plumbing nightmare behind either the Anderson or Nautilus panels will pine for the days when you had a city water connection, separate tank fill and stand alone bypass valve. One needs an advanced degree to figue out how these new and improved systems are inter-connected.

goducks10 wrote:
I sure love the gravity fill on my Northwood. No goofy valves to go bad.

x2!

Lyle

I sure love the gravity fill on my Northwood. No goofy valves to go bad.

With the Anderson valve it's advised to release the water pressure in the system before rotating the valve. If you do not do this it will eventually blow the O ring seals. That's when the fresh water tank fills if the valve is rotated to the city water position. Don't ask me how I know!!! LOL!!!!

Found the water valve switch. The lever is down, indicating only city water inflow, but the fresh water tank is filling, so there must be an internal problem. We'll take it to the dealership. Thanks, everyone, for the input.

Our Montana also has a "switch" to fill either the tank, or use city water while connected, so you may want to check that out as well.

The Anderson valve if you have one and is like the one on Big Horns has 4 positions.

Normal=Pump/tank
City=Hose connection
Fill=Hose fills fresh water tank
Winterize=Pumping in pink stuff

These valves are noted to have o-ring problems. The selector slug is easy to replace.

Chris