2020 T@B 400 Fresh Water Capacity Change?

gspdx

1968Healey said:

Looking for some input here on recapturing the ‘missing’ 8 gallons of water.

It seems like the easiest way to lower the pickup is by connecting a hose to the tank low point drain and hooking that into the input of the water pump.

Borrowing a photo here, you can see the low point drain on the left side (blue/white hose).

This looks almost too easy to do (5 feet of pex and a few fittings) - what am I missing out on?  I could even add a new low point drain with a T fitting so I don’t lose that functionality.

This does sound pretty straight forward.  Does anyone think there is concern that this would pick up "debris" from the tank?  Would it be worth have some kind of inline filter? Any other concerns?

I would certainly perform this same upgrade if there are no other drawbacks.

@1968Healey Please keep us informed of your progress.

1968Healey

I have a progress report, but it's not as straightforward as I expected.

My T@B is in my garage, level front to back and ~2 inches higher on the passenger side than the drivers side (this is just how my garage sits).

I filled the fresh tank to capacity; it was previously drained to near empty.   Once full I ran both the outdoor shower and inside sink into measured buckets and figured out how much water I could pull off the water pump.  I stopped at first when the water pump began stuttering and then I stopped for good once the water pump could no longer pull water.

Then I drained the remaining water out of the tank using the fresh water drain under the trailer.

Here are my results:

Water Pump before stuttering - 100 quarts / 25 gallons
Water Pump 'dry' - 104 quarts / 26 gallons

Remaining water in the tank - 5 quarts.

Now, this obviously is short of the expected 29.75gal capacity.  

The good news is that I was able to get more than 22 gallons off the water pump.  Considerably more.  The bad news is that my experiment is somewhat inconclusive. Where are the missing ~2.5 gallons.  That seems to be too much to be sitting in pipes.

I also, anecdotally, think that I've drained more than 5 quarts of water off my tank after coming home from boon docking and running the pump dry.  This is the first time I've measured, but it just doesn't feel right.

I'm going to let the trailer sit overnight and dry to drain some more.  I'll also measure after our next camping trip (starting next weekend).  Something doesn't fully add up.

VictoriaP

@1968Healey I may have missed it in your post, did you bypass the Alde for this experiment? If not, that may be your missing 2.5 gallons.

N7SHG_Ham

@gspdx there is a filter on the intake side of the pump. Fwiw when I winterized earlier this week, I pulled intake hose off and found a large plastic drill "chip" from someplace during the build.

N7SHG_Ham

@atlasb the sloshing is why I run with tank full. Most of the MPG loss is wind resistance above about 45 MPH and not a few hundred pounds of cargo. Once up to speed it is wind resistance, not weight killing MPG.

Sharon_is_SAM

@1968Healey, I know that our CSS fresh tank will read 100% on the SeeLevel and we can add more if we raise the tongue, so I wonder if you had less than 30 gallons to start.  Also, as VictoriaP noted, did you empty the Alde?

1968Healey

I didn’t touch the Alde when filling or emptying, so maybe that’s it.

I do have the definitive answer about using the fresh water drain to add tank capacity.  Turns out this is the port already used by the water pump, off a T.  Guess that answers that question (or aspiration)....

For the extra ambitious, there is space between the frame rails for significantly larger holding tanks, but it looks like a lot of work.  The fresh tank seems to be pretty ‘custom built’ for the location.  The grey tank on the other hand both has space and looks much more mundane.  That might be a feasible upgrade.

Before anyone asks, I didn’t pull the belly pan just for this.  I’m adding tank heating pads for our winter camping trips in the mountains of Washington and British Columbia.

(Edited for picture size.)

falcon1970

@1968Healey
OK, problem solved--or at least answered.  Looks like the center of the drain tube (which is also the pump pickup) is about 1.5' above the bottom of the tank.  That is why there is about 8 gallons trapped in the tank--whether you are using the pump or merely draining the tank.  So, If you absolutely, positively need that last little bit of water you could raise the off-side of the trailer and gain several more gallons--maybe even close to all of the water in the tank.

gspdx

Another interesting point is that draining the tank via the "low point drain" isn't draining the whole tank.  You would need to raise the passenger side to get close.  Lots of implications there.

@1968Healey Could please document your install of the tank heating pads and provide an update.  I would love to see that too.

rhyno

It also looks like the metal retainer straps are going into indentations in the tank as well. Maybe the inside of the tank is smooth? If not, and even if it's just a slight rise caused by the indentations, those are going to cause any water behind them to dam up as well unless the pax side is raised high enough to get all the water over the hump. I don't see it being practical when camping to raise one side until all the water is used up.

TNOutback

gspdx said:

Another interesting point is that draining the tank via the "low point drain" isn't draining the whole tank.  You would need to raise the passenger side to get close.  Lots of implications there.

That’s why after a camping trip I jack up the door-side of the camper to check to see I’ve drained as much water as possible.  Most of the time though, the tank is fairly empty because I usually leave the drain open while traveling home from a trip.

It also means in preparation for a new trip, I will fill and flush the FW tank a couple of times to drain/dilute any stale water left in there, then do a sanitizing fill.

Denny16

Why waste water, drain the tank, so the sanitizer fill and flush, this will kill the stale water, then flush twice to purge the bleach solution out, or use compressed air to purge the tank.
cheers

TNOutback

@Denny16 Just not knowing how “stale” the water is remaining in there just makes me want to get rid of as much as possible before sanitizing. (We drink the water from the tank.)  I don’t want to put too much bleach in and risk damaging the plumbing, and I don’t want to risk not having enough bleach if the water is particularly “germy”.  Emergency water treatment guidelines say to use 1 tablespoon of bleach per gallon of water to sanitize containers; this is 3X the amount of bleach the T@B owner’s manual calls for.

So, the tank gets a couple of flushes of fresh water to dilute whatever suspect water is remaining in the tank before I sanitize.

Denny16

That is fine, my point is the bleach solution will kill anything in the old water, and several flushing cycles with fresh water will accomplish the same result, purging out the old water and bleach solution, and a fresh tank ready to use.  We drink out of our TaB tank also, md have not had any issues with this procedure.  Beach solution is not going to hurt The TaB’s plumbing (make sure the Alde tank excepted, and make sure  bypass vale is in bypass mode) which is PEX tubing.
cheers