When is full ?

[be18driver]

The wife and I are preparing for our first weekend getaway in our new 2019 Montana 3561. We anticipate dry camping one night. When filling the fresh water tank the manual says to stop when the "full light" turns on. I have little faith in the inaccuracies of the indicator lights. How do you know when your fresh water tank is full ?


Ken

[Gegrad]

You will get different responses, but fill it until it come running out of the fill pipe. You can drain a small amount off after that if you want to so the fill pipe doesn't have water in it.

From an engineering perspective, it is better to fill all the way to reduce forces from the sloshing liquid. A half full tank can exert tremendous force on the tank, especially during stopping maneuvers. Think about a 2 liter bottle half full and then flipping it to cause the water to rush to the other end-- you get a lot of pressure there and force exerted on your hand. Multiply that to 20-30 gallons in a half full tank. Conversely when the tank is full, there is nowhere for the water to slosh to, since under atmospheric conditions water is considered an in-compressible fluid. I would fill it till it ran over then drain a bit off. I am sure others will offer different opinions. Enjoy the trip!

[Canonman]

I fill ours with one of these: https://www.campingworld.com/water-t...CABEgIBtvD_BwE
Mostly because I can't see the "full light" from outside where the FW fill is located
You'll hear the air burping out of the overflow vent by the fill spigot and then eventually water will start coming out. At that point you're full.
Sometimes, depending on how level we are when filling, I'll need to "burp" the tank a couple of times to get it completely full.

[be18driver]

Gegrad
When you say fill till it runs out the "fill pipe" are you referring to the vent outlet at the curb side rear or where the water hose connects to the trailer.



Ken

[Gegrad]

Originally Posted by be18driver

Gegrad
When you say fill till it runs out the "fill pipe" are you referring to the vent outlet at the curb side rear or where the water hose connects to the trailer.



Ken

Vent outlet on the exterior of the trailer where you put the water hose in to fill it. I am not familiar with the Montana though, so it is possible you have a different filling mechanism than I do.

[bobbecky]

The fresh tank vent covers on the newer rigs are usually on the road side at the rear, and don't have a normal fill feature like the older Montana's. The newer rigs can be filled when connected to city water by just flipping the valve in the convenience center to FILL. Once water starts draining out of the fresh tank vent, turn the valve back to NORMAL, and your tank is full. I have used a Harbor Freight 12 volt water pump to fill tanks from a bladder while dry camping, both through the old style gravity fill ports as well as through the city water connection in the convenience center with the valve turned to the FILL position. I even replaced the battery clips on the pump with a trailer plug so I can just plug in to the trailer outlet in the bed of the truck.
Also, I have found that the only tank level sensors that seem to work very well are the ones in the fresh tank, as there is no contamination on the sensors like in the waste tanks.

[Salt Life]

I have little faith in these indictor lights. Never seem to be accurate.

On mine, I hook up at the city water connection and flip the lever to fill the tank until it comes out the manual filling port. But, it's not new or a Montana...

[crk112]

Like most here, I also don’t fully trust the built in sensor lights. I bought a digital garden hose gallon counter on amazon https://www.amazon.com/dp/B0058EOC5M..._Q2UKCb6T6ZSBJ .. my tank is a 40 gallon tank so I just don’t exceed that on the gauge. Easy!

[roadglide]

Originally Posted by crk112

Like most here, I also don’t fully trust the built in sensor lights. I bought a digital garden hose gallon counter on amazon https://www.amazon.com/dp/B0058EOC5M..._Q2UKCb6T6ZSBJ .. my tank is a 40 gallon tank so I just don’t exceed that on the gauge. Easy!

I like the flow meter . There are many times I only haul 25 gallons and that is measured with cell phone clock .I have never noticed any pushing from 25 or 50 gallons of water from the tank . I can tell when I'm full with 110 gallons weight only . I do not use the hose connector to the valve when filling , I stick the hose in the tank fill cape because I don't trust the plastic valve to function right and fill up my water holding tank wile using