Fresh water Tank

TF-Kevin · 10-04-2010, 12:37 AM

This past weekend i was out camping and the park turned off the water, but before they did i filled my water tank, but on the last night before going home the pump woundn't pump anymore due to the low water level, So i looked at the tank and noticed that the line was attached to the side of the tank, and since i needed some water for the next day i drained my water tank into some 5 gallon water jugs, and i filled one and and a half, so there was close to 8 gallons of water left in the tank when the pump stopped sucking the water, is that normal . that is alot i think just to have hanging around in there, so would it be a good idea to run the pump line from the drain plug hole since it is on the bottom. Sorry for the long winded story but i am not much of a writer.
Kevin

turbopuppy · 10-04-2010, 10:46 AM

So - you drained water after the pump started sucking air. I assume your tank's fitting going to the pump sits a little above the bottom of the fresh water tank and eventually water cannot get picked up into the pump suction. It also sounds like your drain is lower on the tank than your pump suction. That is all normal. But 7 or 8 gallons of deadspace? Yeah to me that is significant. But it is nice to know and can be used in reserve from your low point drain.

If on the other hand, a float or other sensor stopped your pump, maybe you could adjust it or delete it so you can pump the tank down further.

NWJeeper · 10-04-2010, 11:31 AM

Our water tank due to it's location is almost as wide as our rig and very thin top to bottom, this doesn't leave much room for the intake port and thus it as well as the "low point drain" are both above the bottom of the tank sufficiently that I am sure we have at least 8gal that aren't useable. I have also noticed that the low point drain is at the front of the tank, the pump draw at the rear on the same side. Thus if you are off level with the nose down the pump port will uncover sooner than the "low point" drain. I therefore used a "T" fitting to plumb the low point drain tube into the pump intake and at least I can get more water out this way.

It's just a case of poor tank design. It would have been better if the tank manufacturer would have put the ports in the bottom of the tank not the side.

jimh · 10-07-2010, 07:56 AM

is it possible that they came off the side to keep debree out of the pump suction? i simply can't think of anyother reason why they would do that.

NWJeeper · 10-07-2010, 10:03 AM

Quote:

Originally Posted by jimh

is it possible that they came off the side to keep debree out of the pump suction? i simply can't think of anyother reason why they would do that.

I don't think so as it is usually not an issue in any RV I have seen. I think it is because of the way the tank is mounted in our rig. I really have to say I don't like it much as it makes a lot of water unusable. For that reason I have devised a way to get more water into the tank when dry camping and a way to filter creek or lake water to make it usable. So far we only use it at our favorite dry camping spot, usually we aren't far from water if we need it.

revrnd · 10-07-2010, 04:01 PM

My brother & I were talking this summer about the "unused" water @ the bottom of my fresh water tank. We were wondering if it would be possible to remove the pickup line from the tank & tie wrap a stainless steel weight to the end of it to get it to the bottom of the tank?

When my pump starts sucking air, there's still about 3" or 4" of water in my tank.

jimh · 10-10-2010, 12:13 AM

i'm not at all firmiliar with how they draw the water. is there a pick up tube or do they just attach to the side of the tank?

if it just attaches to the side and ur talking abt putting a tube from there into the tank, i would cut the end of the tube at a 45 degree angle (to reduce the possibility of the tube sucking against the wall..bottom of the tank and not allowing water to flow in). the other thing is if u are inserting a tube into ur origional suction that leads to the bottom of the tank, u would want to seal the new tube where u attach it to the inside of the line leading to ur pump...to preventing it from sucking air when the level drops below origional suction line.
i would compair it to sucking on a straw with ur mouth partially open or putting the straw square against the bottom of a cup.

MikeA · 10-10-2010, 05:39 AM

Perhaps if the outlet to the tank was relocated the tank could be better utilized. There are fittings available that can be retrofitted to an existing tank. I used one successfully in our last trailer to change the location of the water inlet. These fittings can be installed from the outside of the tank.

revrnd · 10-10-2010, 10:03 AM

Quote:

Originally Posted by jimh

i'm not at all firmiliar with how they draw the water. is there a pick up tube or do they just attach to the side of the tank?

I missed this thread when I asked my question yesterday.

On my Rockwood, there is no pickup behind the elbow fitting. Once the water level is below it, there's no way for the pump to draw water.

revrnd · 10-10-2010, 07:56 PM

Here's what the tank on a Mini Lite looks like from the factory. I imagine those tanks are used in a fair number of models.

I guess if I measured how far the outlet was above the bottom of the tank & multplied that by the length & width, I could find out how much water was left. Also, the bottom "bows" when there is water in the tank, so that would add to the unusable amount.

When I drain the tank, there isn't any water left in it.

crocus · 10-10-2010, 10:10 PM

Makes you wonder why they don't put the suction fitting where the drain sump is?

jimh · 10-11-2010, 06:51 AM

that would be eaisly switched. just a "T" a coupling, and a cap. i would like to know why they went to the extra expense of location the suction on the side of the tank. the only reason i can think of is to keep sediment out of the water system.
from the side, it looks like as low as they could get it and get a bond.

revrnd · 10-12-2010, 09:06 PM

I picked up the fittings, just need to get the hose & clamps. I took some measurements & when the water levels out w/ the elbow on the side, there's approx' 5 1/2 Imperial gallons (almost 7 US gallons) still in the tank.

Dave_Monica · 10-12-2010, 09:25 PM

Take some pictures if you could. This looks like something a lot of people would like to change. We'll all learn from your experience (it's all up to you!)

Dave

revrnd · 10-12-2010, 10:39 PM

Dave, I'm way ahead of you. I was going to take some pics during the mod.

I picked up a typical pipe plug for the tank (already installed, so no pic), 1/2" PEX hose splice/coupling (PN 1443144) to extend the pump inlet hose & the 1/2" PEX T fitting (PN 1441104) to connect the extended to the tank drain.

SaskCampers · 10-13-2010, 07:42 AM

Looks good revrnd.

The only reason I can see for the location is as was mentioned previously, to prevent sediment from getting into the trailer, this of course does not take into account the mixing action from a trip down alot of highways that act like a paint shaker. This is of course no consequence for any units that have the onboard water filter but might be for the others. But I have no idea how much sediment is in drinking water supplies that we hook to.

revrnd · 10-13-2010, 08:44 AM

John, that's a valid concern, but don't we drain/flush the tanks often enough that there wouldn't be a lot of sediment?

In the fall some of us drain as much water out as possible, then add anti-freeze. In the spring the anti-freeze is drained then the tank/water system is flushed w/ clean water. Then the system is sanitized & drained. Most of us drain the tank before towing unless dry camping where water isn't available.

One instance where sediment might be an issue is on park models or rigs that are permanently parked. Mind you those rigs are probably hooked up to the "city water".

Finally, my TT does have a onboard water filter..

SaskCampers · 10-13-2010, 09:02 AM

I totally agree with you about the systems being drained enough as we always dump our tank when we leave our last stop that we needed to have onboard water. I used to pull a full load of water as the trailer always seemed to pull better but am trying to stop that when possible. I think it must have just been in the idea process at the factory.

revrnd · 10-16-2010, 08:29 PM

I assembled my hose & installed it this morning. I'll have to see about tying the hose up or adding a piece of split hose on the X member to protect the hose from the edge.

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