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Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 10:34 am
by Mark
The tanks in my 97 B-190 are third party. I suspect a previous owner drove over something, ripped them out and replaced them. The Fresh water tank hangs quite far below the differential and is only 5 or 6 inches off the ground. I want to replace it and the Gray tank.

I've noticed that the Fresh water tank has a 1.5 inch vent in it. Is this really needed? 1.5 inches? I understand that it needs some sort of vent (water out/air in) but 1.5 inches? The tank does have a "fill vent", a 1/2" tube that vents near the water intake but would I ever need a vent that supplies that much more air volume?

The reason I ask is that if I eliminated the vent (it is right on top of the tank) I could raise the tank that much higher. Could I put it on the side?

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 10:40 am
by skater
I'm pretty sure mine didn't have that vent.

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 10:45 am
by Mark
It certainly seems excessive. I was in construction for a number of years and a full blown home toilet or shower needs that kind of vent but I just can't see it for the level of water I'd be using in my RV.

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 10:58 am
by Mark
I'd really like to see how the original tank was attached. The thing now seems pretty hokey. It's encased in sheet metal and hung via pop rivets and odd sections of "C" shaped metal.

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 12:53 pm
by jb1rd73
I can take some pics of my 94 and post, not sure it's the same as the 97 but I would think so, anyone know?

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 12:57 pm
by jb1rd73
ImageImageImageImage



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Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 1:52 pm
by Mark
Thanks! Great information!

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 2:28 pm
by jb1rd73
Hope it helps, let know how it turns out.

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 2:29 pm
by Mark
It looks like yours are just the raw, not protected tank held on by those metal straps. Is that the case?

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 2:45 pm
by jb1rd73
Yes, just heavy duty tanks held up with strapping, after the lift and 4wd conversion I will add a rock guard but need to see how things get rearranged.

Re: Replacing the Fresh and Gray Tanks

Posted: Sat Jun 14, 2014 2:49 pm
by Mark
A buddy of mine has a much more extensive metal, welded "tray" that holds the tanks. It's nice and bombproof but I'm having a hard time getting a local metal shop to take the job. I can't really draw exact plans for it so it will be kind of a build as you go kind of thing.

Re: Replacing the Fresh and Gray Tanks

Posted: Wed Jun 18, 2014 12:04 pm
by twistedskipper
Is the 1.5" vent actually into the fresh water tank, or into a surround around the tank? Is it currently connected to anything?

On my 1999, there is a ~1.5" duct hose from the LP furnace to each of the below-floor tanks (fresh, grey). These ducts are designed to flow warm furnace air into an outer surround around each tank to provide some heating to the below-floor tanks to prevent freezing, at least while the furnace is in use. These 1.5" duct hoses are routed from a plenum that is in the water heater compartment (accessed by removing the closet floor). I don't know how well they work since this is our first season and we haven't done any winter camping yet. The duct hose to our fresh water tank was capped off when we bought it, so I don't know how it was intended to be connected.

If it is actually a tank vent, as you described it, then I can't imagine why it would need to be 1.5" in the 190. I can't see how you could run water out of or into that tank fast enough to move that much air.

Re: Replacing the Fresh and Gray Tanks

Posted: Wed Jun 18, 2014 12:12 pm
by Mark
Thanks, Twistedskipper,

I was under there yesterday afternoon and discovered just what you describe. The "vents" are actually heat ducts. Since my future instillation won't have the tanks encased, I decided to pull out the ducts and cap them off under the closet floor. I don't plan on using the rig in the winter or anytime it is too very cold anyway.

Re: Replacing the Fresh and Gray Tanks

Posted: Wed Jun 18, 2014 12:21 pm
by Mark
Here is a photo of the tanks I took out.
They were encased in sheet metal boxes and hung from various parts of the frame and floor via a flange on their tops.

Re: Replacing the Fresh and Gray Tanks

Posted: Wed Jul 09, 2014 2:03 pm
by Mark
They just arrived and I just called the welder about making the "tray" for them.

The fresh water tank came .5 inch longer than I expected and then I didn't think to figure in the protrusion of the fittings. They they stick 1" and 1.5" out from the tank. It'll all work but the welder needs to be exact in where they place them.
Tanks.jpg
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