HOW TO: Fresh water tank suction tube mod - NO SPIN WELDING REQUIRED.

[John E Davies]

EDIT 11/02/21. Oliver will do the spin weld mod free if you visit the factory. IMHO they should issue a Technical Bulletin and just fix all the ones in the field, at no charge to the owners. Instead they just changed the technical specs from “32 gallons” to “32 gallons design capacity”. LOL…. How lame is that?

Matt Duncan posted this on Page 2 here in this thread: "I have talked to the service department and management. We will take care of the tank modification for free if you can bring it to our service center in Tennessee. You will need to call 1-888-526-3978 to schedule the tank modification. Let me know if you have any questions!"

I am not sure what Hull number is the cutoff for the new design. Does anybody know? 

JD

—————-

This has been a hot topic lately, and a few people are getting parts, sort of,  but no instructions and definitely no expensive spin-weld tool to install the new 3/4 inch FPT fitting on the top surface of the tank. The factory method is great if you are willing to take your trailer to TN, but for those of us further away it has been frustrating. I finally decided to do this mod using the two existing holes in the side of the tank, and no welding is required. It is a little time consuming but the cost is negligible.

 

It is late, I will write this up tomorrow. Here are a couple of teaser shots:

 

 

 

I added just a few gallons of water to the tank and tried the pump. It ran great all the way down to 16% indicated. It used to cavitate and quit at 38%, leaving about 12 gallons unusable. I raised the tongue two inches and was able to get out 3 more gallons. Another two inches raised, and only half a gallon came out. I am pretty sure the tank is getting almost fully emptied. I can live with a three gallon "reserve" - that is enough for me to finish a shower if I run dry, by just raising the tongue a little to get out that last little bit of water.

 

 

Lots more info later.

 

John Davies

 

Spokane WA

[Raspy]

That looks like a viable fix John.   While looking at mine it seemed really hard to get to the side fittings as you've done.  What tubing is that?  PEX?  If PEX, how did you get the permanent "90" in it.

 

Just a suggestion about the teflon tape:  It might be better to use something like Rectorseal #5 as I showed in my photos because teflon relies on a permanent clamping force to not leak and the plastic tank fittings can relax.  Also, the fittings can crack with not much force and you'll have a leak that will be very hard to fix.   The rectorseal sets to a stiff but sticky glue that is compatible with drinking water and plastic, but doesn't require a lot of constant pressure on the fitting to seal.

 

Looking for your update on the process.

[John E Davies]

That looks like a viable fix John. While looking at mine it seemed really hard to get to the side fittings as you’ve done. What tubing is that? PEX? If PEX, how did you get the permanent “90” in it. Just a suggestion about the teflon tape: It might be better to use something like Rectorseal #5 as I showed in my photos because teflon relies on a permanent clamping force to not leak and the plastic tank fittings can relax. Also, the fittings can crack with not much force and you’ll have a leak that will be very hard to fix. The rectorseal sets to a stiff but sticky glue that is compatible with drinking water and plastic, but doesn’t require a lot of constant pressure on the fitting to seal. Looking for your update on the process.

Hi John,

 

Good info on the Rectorseal. The factory uses teflon tape so that is what I used.

 

The white tubing is standard 1/2 inch PEX, it can easily be heat formed and will retain a strong and permanent set, but it still retains some flex.

 

I’m still in bed (West Coast Time) so I will wait a while before resuming the thread.

 

John Davies

 

Spokane WA

[Mainiac]

Interesting and what appears to be a simple fix. I like it. A couple of questions: while sitting in the cold water of the tank will the 90* bend 'relax' and eventuality straighten out? If the pick up tube was cut on a 45*  at the bottom, wouldn't it draw down more before sucking air? (Is that what you meant with an "angle" cut?). Did you reverse the fill and pick up lines? Surely the factory wouldn't remotely have had the standard pickup line at the top. And maybe it is time for you to put a waterproof remote switch in for the electric front jack. The thought of you rushing out to raise the front of your trailer, halfway through a shower, maybe just disrupt a campground...

[KarenLukens]

And maybe it is time for you to put a waterproof remote switch in for the electric front jack. The thought of you rushing out to raise the front of your trailer, halfway through a shower, maybe just disrupt a campground…

Now, that's scary stuff there this close to Halloween :)

 

It looks good John, why didn't you just use copper and take it all the way down to the floor in the corner? Either way, it's a lot better then it was :) Nice job :)

[John E Davies]

!!! NOTE: THIS MOD WORKS WELL ON MY ELITE II, HULL NUMBER 218. EARLIER HULLS THAT DO NOT USE QUICK RELEASE PLUMBING FITTINGS WILL BE MORE DIFFICULT. Even if your trailer has these newer fittings, your configuration may be slightly different which will require some re-design.

 

As always, do this at your own risk. It will not void your factory warranty, but Oliver certainly will not help you with stuff that your altered from the factory configuration, without charging you for their labor.

 

_____________________________________________

 

Here's the full installation, with pics. I will answer specific questions after I have finished, to avoid repetition and confusion....

 

I noticed that the two lines attached to the water tank are parallel and about three inches apart, the same spacing as the holes in the tank. After a lot of pondering, I decided to swap the lines so that:

 

The lower Pump Suction/ Gravity Drain port becomes the Tank Fill port.

 

The upper Tank Fill port becomes the Pump Suction/ Siphon Drain port.

 

I think that this is an elegant solution since you can easily reposition the lines top to bottom, and also easily swap the two existing elbow sections that go vertically to the pump manifold. So the only fabrication involves making a new curved dip tube to go into the top hole, and a few unexpected but easily fixed problems associated with doing that. The system is not really changed except that the water now flows into the tank at the bottom, and the water is sucked off the bottom of the tank through the top port, and can also gravity siphon to drain it through the same line. And it is all easily (but not quickly) reversible to put the system back to "factory configuration".

 

I would really rather have a new spin welded fitting on top, but I can always do that later if I decide it is necessary. I never understood why there are fittings on the side of the tank anyway. They are not needed and they just develop leaks. ALL functions of a fresh water tank system can be done through the top of the tank, where leakage risk is very minor.

 

View of the original system, with the heat duct lying in the way.

 

 

The heat duct is pulled up and to the outside and secured with long nylon cable ties. Access is pretty easy with it held there. The white arrows show direction of water flow. We will be REVERSING those.

 

 

First and most important, manufacture the curved dip tube. Once that is made correctly, you can start disassembling lines and fittings.

 

Clamp the 1/2 inch PEX hose in a vise, leave lots of its length extended to work with. You need a good hot heat gun, not a hair dryer, to get the plastic warmed up enough to soften and reform. Once cooled it will maintain its shape.

 

 

Stick a big screwdriver in the end and carefully heat the curve over a span of about 6 inches, moving the heat gun back and forth and around so that you do not melt the plastic. If it starts to turn gray you are over heating. Apply pressure to force the bend, you will feel it start to move. Do this SLOWLY and always keep pressure on the screwdriver. The inside will try to kink as the outside stretches. That is OK unless it is major collapse, in which case you need to try on a new section of tubing. You will have to drastically over-bend the curve since it will spring back about 45 degrees when your are done.

 

 

The hose will try to flatten. A little is OK, but you can squeeze it with pliers to force it back to a round shape. Keep heating the plastic!

 

 

When you are happy with the curve, remove the heat and hold the screwdriver in place for at least a minute for the plastic to cool. release tension on the tool and the pipe will spring back to about 90 degrees, a little more is better than less. It took me two tries to get this right. I wanted about a 100 degree bend. Anything more and it will be hard to get into the tank opening. Less will move the pickup opening away from the rear wall of the tank, which is the most desirable spot.

 

 

This is the finished shape. Elbow length is not critical, it needs to be at least five or six inches from the unmolested section. I cut the area that will lie near the bottom of the tank at a steep angle, to lower the top of the hole (which is the first place that will suck air). It is important to keep the angle steep, say no less than 60 degrees, since you do not want the cut to be perfectly parallel with the bottom of the tank, or it will suck down and block the opening when you turn on the pump. You want to scavenge as much water from down low as possible. I added scallops - vee shaped cuts - at a few places on the end to increase the opening size and also make it impossible for the tube to suck down hard against the bottom. They are probably not needed, but they will not hurt.

 

 

The length of the straight section is not critical, leave it long since it will be trimmed after installation into the tank.

 

More to come.

 

John Davies

 

Spokane WA

 

 

 

 

[John E Davies]

Compression fitting. There is a "pass through" version available, but it is not commonly found in box stores. I used a regular version with internal stop, and I removed that section.

 

The threaded port is 1/2 inch FMP, so we need a fitting with a MPT and also a 5/8 inch opening (the PEX hose is 5/8", as is a copper pipe).

 

 

I drilled out the passage way using a regular 5/8 inch bit, followed by a 5/8 inch Forstner wood bit to clean up any rough gouges. You can do this with a file but be careful not to damage the cone seat on the left side, or it will leak.

 

 

 

Ideally a PEX tube should have a metal insert inside to help support it when you tighten the nut. This is not possible in this case.

 

More to come.

 

John Davies

 

Spokane WA

[John E Davies]

Disassembling the factory plumbing.

 

A word on the quick connect fittings. To remove a line, rotate the collar counter clockwise 90 degrees. The inner sleeve will push out. Press the sleeve inwards with a finger or tool and that will release the pressure from the o-ring.Pull the line out of the fitting. Assembly is opposite, just be sure all parts are clean.

 

View of the system, white arrows show water flow. The flow in these locations is NOT changed. The two elbow sections (with white arrows) will be swapped since the lines they connect to down low will have different heights. One will drop 3 inches, one will rise 3 inches. There is a tee visible to the left in the shadow, and another hidden under the duct at the lower part of the pic.

 

 

Remove any black clamps as needed to gain working room. Do not drop any of the stainless clamp screws down into the hull - they are non-magnetic and may be very hard to retrieve! Disconnect the two upper elbow lines. Use a towel to catch any water. It isn't necessary to label any parts.

 

 

Working at the lower tees, disconnect and remove both elbow lines.

 

 

 

Here is a closeup of the two lines we need to swap to different ports. The shorter section will be discarded and replaced with the new curved dip tube.

 

 

Remove the lines from the tank using a 7/8 inch wrench. There is adequate room. Be aware of the circuit breaker board for the water level sensor, do not short it out! You could cover it with duct tape if you feel klutzy...

 

 

 

 

Here are the bits that have been removed. All will be reused except for the short straight section which can be tossed or placed in a junk drawer. I worried a little that reusing old pipes in new locations would result in leaks, but I had none. Your mileage may vary. You could always install new line and fittings if you are a worrier.

 

 

More to come.

 

John Davies

 

Spokane WA

 

 

[John E Davies]

Reinstalling the factory plumbing.

 

Install thread sealer on the CLEAN pipe fitting of the long line and install into the bottom port and also the rear tee. This line will lie nicely on the floor. Raspy recommends in the second post to use Rectorseal #5 for a better seal. The factory uses tape, and I had no leaks using tape.

 

 

Insert the long elbow line into the rear tee and the appropriate Tank Fill fitting on the manifold, as shown. Secure the tee collars down below since they will be harder to access afterwards.

 

 

View of the lower hose installed, showing that you will need about 9.5 inches of extension to properly seat the new tube into its tee fitting, past the o-ring; make sure you have MORE than this length left when you make the tube. You will trim to length after installing it.

 

 

Test fit the new tube into the upper port. I was expecting it to slip right in, but the hole in the side of the tank was drilled undersized (1/2 inch). This is poor practice since the barrier will trap water and possibly cause freeze damage. There should be a small weep hole drilled at the very bottom of any vertical opening to keep it water free in winter storage. The guy who welded these fittings on could have done that in about a minute.

 

 

Note, this is pretty hard to see without a good mirror, I just stuck my cell phone down low and looked at the pics. I had to open up the hole to allow the 5/8 inch OD tube to go through. I used a coarse, large rat-tail file (with HANDLE so I could not lose it inside the tank!) while sucking up shavings with a shop vac. Any residual shavings will collect in the filter for removal. Be very careful if you have to file, to prevent damage to the pipe threads or it will leak.

 

 

It's not pretty, I guess you could use a straight soldering iron to melt the edges.... but the fraying doesn't really matter. I marked the approximate location of the old Water Line, where the pump will suck air and cavitate, and also the location of the new line. This difference represents a lot of extra usable water.

 

Make SURE this is very clean before installing the new tube. I used a blast of compressed air.

 

More to come.

 

John Davies

 

Spokane WA

 

 

 

 

 

 

[John E Davies]

Installing the curved dip tube.

 

Insert the short end into the top opening and push it inward while rotating counter clockwise. This rotation will keep it from colliding with the top of the tank.

 

 

 

Screw in and tighten the pipe fitting. Do not over torque, light pressure is all that is required. Do not connect the compression nut yet.

 

 

Pull outwards (to the back) on the dip tube to position the other end as far back as possible in the tank, and mark the location of the cut. Make sure the length is correct so that the end is well past the o-ring. about an inch from the opening of the fitting. Push the tube forward into the tank and cut the line.

 

 

Insert the cut end into the tee fitting. Do not tighten collar. Pull back as hard as needed and rotate the dip tube toward you so that it is hard on the bottom. Make sure the newly-cut is past the 0-ring! Tighten the 1 inch  compression nut while holding the line with large pliers to keep it from turning. Also use a 7/8 inch wrench on the tank fitting so that it doesn't turn. It really needs three hands, but you can position the wrenches so that you squeeze with one hand while holding the line with the other ... or you can borrow a helper.

 

It's hard to tell how tight to adjust the compression nut. I did it moderately, checked to see if the tube would turn, tightened a little more, until the tube was tight and could not be turned easily with pliers.

 

With the dip tube secured into the tank, insert the short elbow line into the tee and appropriate fitting on the manifold. Secure the collars. Draw an arrow on top of the new tube showing flow.

 

Before securing all the clamps on the manifold, it is necessary to leak check the system.

 

Fill the tank with a few gallons of water using the outside fill port and turn on the pump. WOOHOO, it works! Check for leaks in all the pressure connections - it should be easy to see them. For the suction and fill lines it is harder. I like to use a blue paper shop towel folded up and placed underneath a fitting. If there is a leak, even a small seep, it will show up as an easily visible dark spot.

 

 

I filled the tank half way and checked the bottom fitting for leaks. None were present after 30 minutes. I then filled it to the top and checked the top fitting. There was an immediate leak at the compression nut. I turned it about 1/3 turn until the leak quit. I left the towels in place overnight and they were dry in the morning.

 

A leaking tee may be fixed by repositioning the line slightly, but you may have to try a new tee or line. I was pleased that the repositioned lines did not leak. I expected at least one leaker....

 

Clean up the area, secure the manifold tees with their clamps, check for left-over tools, reposition the heater duct. I left a blue shop towel in the bottom as a tell-tale in case of future seepage.

 

 

 

More to come.

 

John Davies

 

Spokane WA

 

 

 

 

 

 

 

 

[John E Davies]

Summary:

 

It remains to be seen how well the dip tube connection endures the rigors of trailering with 32 gallons of water sloshing around. If it seeps, I will tighten the nut. If it continues to be a problem, then maybe the official spin-welded fitting will be needed. I will not know for quite a few miles, but I think it will be fine.

 

I can imagine a situation where the suction dip tube has air in it from trailering, and you can't get water to flow out the tank drain. Simply turning on the pump should clear the line of air and start the siphon going.

 

Attached are the original water capacity placard I made up shortly after I got Mouse home, and the new one I just made. There is quite a difference in usable water, I think this mod is definitely worth doing, unless you are forever connected to city water at your campsites. Note that while I did measure capacities while filling and emptying using 5 gallon buckets, there is some error and the numbers are not 100% accurate.

 

I plan to print the new placard,laminate it and place it above the Tank Monitor in the trailer for easy reference.

 

I checked the water filter after a few minutes of operation and it was FULL of white shavings, but I have never cleaned it before, so that may be a present from its birth in Howenwald. I plan to check and clean the filter every few hours until I see no more plastic shavings.

 

Comments, questions and possible improvements are welcome.

 

Oh yes, I never planned to run naked outside the trailer to raise the tongue if my shower ran the tank dry. I would most likely scream at my wife to do that.... with clothes on.

 

John Davies

 

Spokane WA

 

 

Fresh-Water-Capacity-Placards.docx

[John E Davies]

John, why didn’t you just use copper and take it all the way down to the floor in the corner?  

Reed, I was concerned that a rigid dip tube would be hard to work into the opening since the maneuvering room in the compartment is a little limited. A plastic tube has enough flex that I did not envision any trouble. It indeed went right in, once it had the correct sized hole.

 

If the side tank fitting were 3/4 MPT instead of 1/2 MPT, then maybe a copper pipe would go in there.

 

I know you did this kind of stuff for a living, I would greatly appreciate any comments and tips.

 

John Davies

 

Spokane WA

 

 

[KarenLukens]

 <span style="line-height: inherit;">I know you did this kind of stuff for a living, I would greatly appreciate any comments and tips. John Davies Spokane WA

</span>

 

Actually, I was going to do basically the same thing but with copper until Raspy came over with all of the parts in hand for the 1" spin weld after doing his :) I had never seen pex permanently bent with heat like you did until today.

 

Once again, Nice Job!

 

Reed

[SeaDawg]

Upinor PEX in our home bends once, easily. You can even use a heat gun to seal a leak.. one time. Ditto on bends.

 

A second run with a heat gun was not recommended, at least with our type of PEX.

 

Great thinking and invention, John. Thanks. Let us know how it works for you.

 

 

[DavePhelps]

Wow, quite a thread John. Thanks for diving in to this.

 

Still not sure why you decided to swap the intake/outtake lines out. Wouldn't it have been just as easy to put the new siphon tube in the lower hole? Or were you worried (as I am) about access down there. Curious to see how well your setup will work when it comes time to drain the tank. You may have to get under you Ollie and suck on the exterior drain port to get it all going! But hopefully not.

 

Curious also about your pic of the factory spin weld fitting. It appears to be of a different design than the one that was sent to us. Can't figure out why there would be any tank showing inside the fitting as there has to be that collar on the weld side of the fitting to key in the fitting for spinning. That collar is larger than the FPT part of the fitting. To have to file the tank out to get the tube through is a real PITA. I asked Oliver about months ago as I was worried about this very thing. They assured me that 1/2" pex or copper would go through. Hmmm.

 

Finally, do you think in hindsight that you could have gotten a copper bend in your tank instead of the PEX bend you made? I'm a little worried about the PEX in a compression fitting that is unsupported by the little support sleeve that came with that fitting. I think copper would better resist deformation by the compression ring in a pass through situation. But perhaps with the pressures we are talking about, the PEX will do fine.

 

Thanks again for the write-up. It must have taken a bit of time and is appreciated.

 

Dave

 

 

 

 

[Raspy]

Good work John!  Nice fix.

 

You can put pipe dope on the compression fitting ferrule and nut threads to act as a lubricant and sealer which will allow much less torque without leaking.  I suggest anyone else that does this use Rectorseal 5 on the tank fitting, but teflon will work well if you're careful. Just be careful not to tighten it beyond hand tight.  I don't think you mentioned it, but when tightening the compression nut, everyone should be careful to hold the fitting on the hex nut with another wrench.

 

When I was looking at mine, I never thought of swapping the top and bottom fittings to gain access.  Good idea.

[ScubaRx]

...I checked the water filter after a few minutes of operation and it was FULL of white shavings, but I have never cleaned it before, so that may be a present from its birth in Howenwald... John Davies Spokane WA

 

Doubtful, since Oliver buys these tanks with the fittings molded in.

[John E Davies]

John E Davies wrote:

…

I checked the water filter after a few minutes of operation and it was FULL of white shavings, but I have never cleaned it before, so that may be a present from its birth in Howenwald…

John Davies Spokane WA

Doubtful, since Oliver buys these tanks with the fittings molded in.

I did not mean the tank was born in TN, but that it was installed there, I probably mis-phrased that comment.

 

The fittings are not molded in (just look at the pics), rather they are spin welded in place afer the holes are drilled, thus there are shavings inside. The company that made it should have flushed out shavings after manufacture. But we all know how these things work. Lots of RV owners have found much worse in their tanks, like 3 inch discs of plastic.

 

It is very important to check the pump filter routinely, at least until you no longer find manufavturing stuff in it. For those who haven’t ever done it, the bowl screws off by hand and you can easily swish it and its mesh screen under running water to clean it. It takes about a minute to do, once you have the access panel open. Only a tiny amount of water will spill, and you can catch that with a couple of paper towels.

 

John Davies

 

Spokane WA

[John E Davies]

Wow, quite a thread John. Thanks for diving in to this. Still not sure why you decided to swap the intake/outtake lines out. Wouldn’t it have been just as easy to put the new siphon tube in the lower hole? Or were you worried (as I am) about access down there. Curious to see how well your setup will work when it comes time to drain the tank. You may have to get under you Ollie and suck on the exterior drain port to get it all going! But hopefully not. Curious also about your pic of the factory spin weld fitting. It appears to be of a different design than the one that was sent to us. Can’t figure out why there would be any tank showing inside the fitting as there has to be that collar on the weld side of the fitting to key in the fitting for spinning. That collar is larger than the FPT part of the fitting. To have to file the tank out to get the tube through is a real PITA. I asked Oliver about months ago as I was worried about this very thing. They assured me that 1/2″ pex or copper would go through. Hmmm. Finally, do you think in hindsight that you could have gotten a copper bend in your tank instead of the PEX bend you made? I’m a little worried about the PEX in a compression fitting that is unsupported by the little support sleeve that came with that fitting. I think copper would better resist deformation by the compression ring in a pass through situation. But perhaps with the pressures we are talking about, the PEX will do fine. Thanks again for the write-up. It must have taken a bit of time and is appreciated. Dave

Dave, lots of good questions here. This entire scenario is one big compromise, since ideally all fittings should be above the static water level from the every start....

 

Siphon tube in bottom hole: Access is a real problem, you still would have to remove both sets of lines to reach the area, and if you had a leak in the siphon, you would have to take both apart to repair it. With the tube on top, the bottom fill line does not have to be touched, and the fill line is the only one that has positive pressure in it, so it is most likely to leak. It is prudent to just not mess with it a second time.

 

Siphon tube in top hole: Easy access after the installation, the static water pressure on the connection is less (less water that high up), so it is less likely to leak. Ideally, one mounted  on the very top surface e of the tank (like the factory mod) has zero static water pressure, so it can never leak unless your are towing.

 

Draining the tank: It should not be a problem, When the line is full (no air pockets) it will drain naturally and do so until it sucks air. If you try to drain the tank after towing, there will be air in the line and _maybe_ nothing will happen. Simply turn on the pump and it will  fill the line. If you want to get anal, open the ball valve that sends water to the tank and the pump will recirculate water in a loop and completely clear the line of bubbles. Once the air is gone, the siphon will start when you open the drain valve. Or you could just raise the tongue 6 inches, as you normally would, and it will force a siphon action by piling the water up in back. No sucking on the pipe under the trailer!

 

You still have to raise the tongue regardless to get the remaining few gallons out....

 

Spin weld fitting: I can't answer your questions since I have never even seen a spin weld tool in person. The fitting that Oliver sends in the kit looks the same to me, except it has a back flange to slip into the tank wall..

 

 

Hole in the tank: It is 1/2 inch, you cannot slip a 1/2 inch PEX or copper tube through it since they both measure 5/8 inch outside diameter. When you are talking about a CURVED tube, you need even more room for the bend.

 

PEX vs copper tube: I thought a long time about this and I considered the environment that the tube would have to endure. A fixed tank in a structure does not have any water movement. An un-baffled water tank in an RV, especially a long and low one like this, can sometimes have incredibly violent water motion. When full, the water can't slosh when you slam on the brakes. When 3/4 full, you have a large amount of water that is thrown forward by inertia, then it rebounds and sloshes back and forth. Water has a lot of mass (have you ever had anybody throw a five gallon bucket of water at you?) and that force gets transmitting to the tube in back.

 

A copper dip tube will have no give and much of the energy will go up to the compression fitting. I would be really surprised if it did NOT develop a leak over time. A PEX tube has a significant amount of flex and will dampen out a lot of the force.

 

I actually pursued this idea at first, since when I got my parts from Oliver I thought all the tank fittings were 3/4 inch, like the one they supplied in the above picture. Not everyone has the ability to heat and bend a tube, so I thought using off the shelf Home Depot parts would be a good compromise. It does require a PEX crimping tool, however.... Here is a standard $6 "stub-out" going through the drilled out fitting supplied by Oliver:

 

 

[attachment file=76435]

 

 

Pretty slick, eh? I was proud of it! I drilled three angled holes around the closed end and it is very nice to look at, but it won't go through the existing holes on my tank. Maybe yours has 3/4 fittings installed, in which case this would work fine. However, there is a significant restriction where it is swaged down into a nipple for the tube, plus it has the risks I mentioned above. So I can't really recommend this.

 

PEX tube and the compression fitting: I think this is the weak spot of this design, no doubt about it. If there was a good way to insert a thin metal sleeve where the crimp occurs, it would be better. The fitting Oliver supplies for the top location has an o-ring under tension, so it should theoretically remain leak free.

 

You still have to drill it out though, they do not supply the correct fitting for a pass-through. For my Beta test pipe I used a 3/4 inch Forstner wood bit. I pushed a piece of tubing all the way into the fitting to protect the o-ring, drilled out the restriction, until I hit the PEX tube, then pushed the tube all the way through, de-burred the end, and pulled it back out. It's really easy if you have the bit. It takes about five minutes.

 

 

I think my setup is as good as it gets, using the two factory holes. I think a 3/4 or 1 inch spin welded fitting on the flat upper surface would be better if you can get it done. I will keep an eye on mine as I tow, and if it doesn't work out I can easily put it back the way it was.

 

Did that cover all your concerns?

 

As a final comment, if I am ever back in TN (doubtful) I will have Oliver add a top fitting and plug it. Even if my setup hasn't leaked by then, it might in the future and then I would re-route the suction line through the new top opening and return the rest of the plumbing to the original configuration. But I would probably just plug the bottom hole and rely on only the top siphon for draining.

 

John Davies

 

Spokane WA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Raspy]

When I first looked at this problem and was working on a solution, I quickly gave up on using the existing tank fittings because of the poor access.  John's fix using the upper fitting helps to get around this problem.  Dave had already come up with a copper pipe formed into a Z, sort of, shape to fit through the existing holes and then lay on the bottom of the tank. That seems like a good idea too, but hard to install in that lower fitting, in fact, next to impossible to install.

 

The use of 1/2" PEX (5/8" OD) means it's too big to fit through the hole and John had to enlarge the hole to get it through.  Another method would be to use 3/8" PEX (1/2" OD) or 1/2" copper tubing.  And then adapt back to the 1/2" PEX outside the tank.  John's curved copper example is good, but the bend is too sharp to make the corner.  A hand formed 1/2" copper dip tube 90 might work very well if someone wanted to use copper instead of PEX.

 

I debated between using copper or PEX for my dip tube coming in through a fitting on top and decided that copper was best for  me.  I was able to make the holes in the pickup so close to the bottom of the tank that mine will draw down to 6% before getting air and will struggle on down to zero percent with some bubbles.

 

Those plastic PEX fittings that seal only with an O ring against the outside of the tube seem barely good enough and may leak with the sloshing water and vibration while driving.  The drilled out brass fittings John used are much better.  And they can be easily taken apart if needed.

 

I want to re-stress that the tank fittings, especially the ones from the factory, are not very strong and can crack if the fitting is screwed in too far.  Be careful!

 

When using the copper crimp rings to connect the valves or splice the tubing, the tool can be cumbersome and hard to get in place.  Lowes sells another one called a "pinch ring".  The tool for these is more compact and works well.  The rings are also stainless and can be removed easily if needed.

[John E Davies]

I just remembered another reason I decided against copper.... the risk of splitting when the tank contents freeze. It might only affect an inch or two of material right at the bottom, but that would prevent it from drawing from as far down next season.

 

PEX is much more tolerant of freezing. I’ve had a couple of residential copper lines freeze in really severe cold and I don’t care for that, no way....!

 

In regards to restrictions or using smaller tubing, that might work but it is not the best solution. For a suction line, there needs to be minimal restrictions (narrowing or sharp bends) and ideally the suction line should be the next size larger diameter all the way to the pump. With the small pressure and flow rates that RV pumps are capable of, it isn’t a big deal, but you should be aware of this when you start thinking about changing stuff....

 

John Davies

 

Spokane WA

[KarenLukens]

I don't think that the copper would split in the tank because there is no pressure on that line, if someone did let the tank get cold enough to freeze, it would freeze in place and maybe expand a touch, as could the pex and the tank would probably split... Either way, letting the tank freeze with water in it at the rear is a bad idea, by lowering the tongue either back to level or forward a bit after draining the tank as low as possible, the remaining water would be out of the area of the dip tube anyway leaving no way for any accidents.

[DavePhelps]

I've been learning a lot here. Lots of great ideas and techniques posted and many thanks to all who have contributed.

 

Having looked hard at my Elite and considering all that has been presented here, I can say for certain that the only way forward for me is to spin weld a fitting on top of the tank. There is just no room at all to work with the existing fittings, even using John's technique. The water heater tank mostly centers on the back of the FWT, completely covering its fittings, there is no room. Even if I was to remove the hot water tank, which would be a huge project for me, there still would be minimal room with high chance of failure. You can just make out the back of the FWT in this pic:

 

 

There is a clear area on top to spin weld a fitting but it is about 12" forward from the rear of the tank. I guess this means I would have to use a longer siphon tube that would reach to the back of the tank, which is where I believe it should be located. Tape is hooked on back of FWT above fittings.

 

 

I sure wish Oliver was a little more supportive about this issue. At least identifying shops that could do this work for us folks who live very far away from Hohenwald.  I told them about this issue 04/15 when we kept loosing prime on our trip home. It didn't take long to discover the problem. I still am in disbelief that, as well conceived as the Olivers are, that this PITA water system ever got off the drawing board. Sure glad we all have each other to help make our Olivers what they should be- the very best!

 

Dave

[John E Davies]

Bumping a four year old thread. It might be of interest to folks who have not fixed their tanks yet. My mod is still working well, with no leaks, though air gets into the plumbing more readily than with the old almost  “bottom of the tank” location. I can live with that.

John Davies

Spokane WA

[JohnL]

Is this a problem that has been corrected in the production of later models? My LE II #769 rolled off the line 03/2021.