SOLUTION: The ultimate fresh water transfer pump

[ShrimpBurrito]

Possible solution #4:

Install the new city water flange under the bathroom sink, where there is plenty of room. I confirmed with the Shurflo tech that this pump can self-prime up to 9 vertical feet. I'll need to measure a bit to confirm, but I think that will be enough priming power even with the pump under the kitchen sink. But if not, I can mount the pump under the bathroom sink as well, which is even more fun to work under than the kitchen sink.

Dave

ShrimpBurrito,
I think your easiest method for the 2720SL may be to keep it all outside and add an new pump.
Our acrobat contortionist plumbing days may have past. <grin>
Put it underneath TM , "T" into water tank drain. And NO VALVES! No pressure switch needed on the new pump. No new holes in walls.


Mount the pump, switch , wires, elbows and city water flange to a board. (so you are not upside down as much)
Under your TM "T" into water tank drain line above drain valve. Run a tube from the new "T" into the pump.
If you make the new tube flexible and a foot or two long - then the assembly on the board can sit on a box until everything is done and tested.
Then when it all works, screw board to bottom of TM.


Where to run power wires? I'd have to look at your TM. Maybe run up side of hole the drain tubes occupy. Add fuse near power connection source on hot wire. Or have wire come out of a cabinet and plug into lighter socket.

If your new pump does not have antisiphon:
----Then add a one-way valve between new "T" and pump.
----Nothing to turn on/off in the one-way valve - it just keeps your tank from running out thru the new pump.
----Sample of: One way valve / RV City Water Check Valve http://www.rvtruckparts.com/ProductD...ID=192&CID=777


Think about switch location so it can't get wacked by weeds or road rocks and accidently turned on for hours until battery dies.
Think about city water hose size - a big hose may hold a few quarts of water.
Maybe when jug is empty just lift hose end high while pump is on to get it all.
Maybe build or buy a box to cover entire assembly underneath.



Hope this helps.
My brain in now empty for while....

.

[ThePair]

ShrimpBurrito: Sorry, my outside hose comments were directed at LiveTicker, not you.

That vent hose was never attached, and when I try, the hose and the outside attachment point seem to be the same size. Which tells me there is probably some kind of connector that is missing (was always missing) that I could probably get from Lowe's, if I bothered to measure the tubing diameter. (1/2" ?)

I've got an SL and I am still very interested in this whole concept. I know that I'm at my limit weight-wise for towing, so using something like the single pump for double-duty is very interesting to me. I think I might just take a peek under the sink of my TM tonight if I get the chance, see how tight some of these concepts might be.

As it turns out, Evsco is literally minutes away from my house! I may try to contact them in the next day or two, see about that 4-way and what it costs, and see what it would take for that hookup, if it makes economical sense. Otherwise, I plan to look into the modified v4 plan.

Now all I need is to learn how to manage PEX tubing :P

[ShrimpBurrito]

ThePair - I know every pound counts, but the pump probably only weighs 3 lbs. Definitely weighs more than a bottle of wine or six-pack of beer. I know, priorities, priorities.....

If you do install a valve, where are you going to put it?

Note that Sharkbite connectors work wonderfully on PEX. If you only have a few connections, I'd go that route (and I did) vs. spending the money on a good crimper.

Dave

[ThePair]

I just took a look, and if I unscrew the drain pipe from the sink I should have enough room to do whatever. I think the valve would just go there. As it turns out, the inlet hose to my pump has a kink! So, I can fix that at the same time as working on the rest of this. From what I can see, the 4-way would fit in this space on the tank, behind or next to the drain elbow. I would potentially need a 90deg pex corner for the AB splice, and maybe just some extra flex tubing for the CD with appropriate connectors if I chose to go that route. If I go with the v4a method, there's enough room to do that too, I would consider putting the 3 way valve right at the pump inlet, and then run pex from the top port to T into the city line, with the reverse flow preventer just downstream of the T. Either one looks to me like it might just lay in well, and even unkink my input line, so it may just come down to cost.

[ThePair]

Ok, looked into it. The 4 way I linked to above is looking to be too expensive, although the "extra parts" needed would be minimal. v4a needs more parts, but I think will end up quite a bit cheaper. I'm going to seek out all the parts for each, get a total, and evaluate from there.

Edit to the above: I've got a bead on a very reasonable 4-way valve (friend of a friend favor) so I'm going that route. Anyone used Flair-it connectors for the PEX (vs. Sharkbite)? They're much less expensive--like 50% of the cost--and look to me like they'd work just as well, if not being a little more bulky than sharkbites or their ilk.

A nice side-effect of the 4-way, I think, would be to allow filling of the entire water line with one connection while the TM is closed (the high-pressure port). So, once I've put the 4-way in, I will convert just that line to external fill, and see if it works

[ThePair]

Ok, my version 1 is installed and working as planned, with one unfortunate and unforeseen problem. The 3-way valves I used (decided not to use the 4-way as the flow ports were tiny, and I didn't want a permanent restriction on flow in the water system) are high-flow, with the downside (which I didn't realize until testing) is that they allow cross-flow in the wrong direction. So, the upshot is that the water pump won't shut off, because the high pressure side is leaking water into the low pressure side. So, for this trip starting tomorrow, we're going to have to flip the pump switch on each time we want water, then turn it off. Ugh.

The good news, is that the theory is sound. I haven't tested using the pump to refill the tank (the whole point of the thread!) but I have been able to fill the whole TM system just using the pressurized drain pipe. This results in a very fast fill, without needing to raise the shells.

To fix the pump problem I'll need one more valve. I already know where it needs to be installed, and that should solve the problem. A different set/brand of 3-way valves might not have this issue, depending on how they're constructed. But, at least there's a relatively easy fix for the work I've already done.

I'll post the pix after I've made the fix.

[OneMoBear]

All of these ideas are brilliant, as usual. However, we are going to take a slightly different approach. This thread reminded me of one Wayne (RVHarvey) had previously posted about installing a deckplate in his holding tank for cleaning purposes and I thought "Hey, that would work for refilling too!" Anyway, we've ordered one and the plan is to toss the cushions out of the way, open the deck plate, and use the handy support provided by the holding tank. I don't know if this would work for every model or everyone's individual needs but for us, what's not to love about this?

Malinda

[Wavery]

Originally Posted by OneMoBear

All of these ideas are brilliant, as usual. However, we are going to take a slightly different approach. This thread reminded me of one Wayne (RVHarvey) had previously posted about installing a deckplate in his holding tank for cleaning purposes and I thought "Hey, that would work for refilling too!" Anyway, we've ordered one and the plan is to toss the cushions out of the way, open the deck plate, and use the handy support provided by the holding tank. I don't know if this would work for every model or everyone's individual needs but for us, what's not to love about this?

Malinda

I used the "Deck-plate" as a tank clean-out port. When I first got the trailer, I could see pieces of plastic in the bottom of the tank. When I cut the hole in the tank to install the deck-plate, I found that there was a layer of sediment in the bottom of the tank (sorta like sand).

I've never used that plate to fill the tank (in fact, I haven't used it since ) but it certainly could be done. It would be a heck of a lot easier than trying to use a funnel in the fill hole...

When you install your deck-plate, be sure to get some thick, soft gasket material or plumbers putty to put between the plate and the tank to keep it from leaking. Silicone sealer may work but it may not. It will not adhere to that polyethylene plastic tank.

[OneMoBear]

It comes with an o-ring and we'll heed your sage advice once again.

Malinda