Nautilus P3 Flow Diagram

Denny16

“Denny16  “ Snoblett has a 2021 with Nautilus and it only has 1 hot and 1 cold low point drain.  The Alde drains via the cold line.

I guess you don’t really need to bypass the Alde - just open a faucet and drain some water via the low point drain!  Just make sure the pump is off and the city water is turned off!” Sharon is SAM

Thanks Sharon, modified my post to reflect your correction.  Also your tip to open the cold water low point drain should restore the air cushion just fine on the newer TaB400s with the two low point drains.
 Cheers 

Sharon_is_SAM

It should @Denny16.  After all, holding down the yellow drain valve does the same thing, albeit more directly.  This gives owners a way to avoid lifting the bed - which is where we started with this😂

MuttonChops

Must share . . . not ready for prime time . . . but must share

Am attempting to create a color coded 3D Model of the primary Four Valves.  As the Mfg Installation and Service Pictures are difficult to view with nearly everything Black Pipe.

This is a slowwww work in progress when completed it might provide helpful reference material when Owner Repairs are undertaken.  Will release an updated version of the PDF posted earlier in this thread when something useful has been completed.

Early Example:

Full document posted later in this thread. Dec-06-21

Binghi

That looks great, MuttonChops - I look forward to your future work!

Snoblett

@MuttonChops
Dang!!! You’re good!  Yes, visualizing a screenshot from an Installation Manual of a black manifold was not an easy task when I put together my iPhone marked up photos of the flow diagrams for each configuration.

In case you have not already determined this additional detail, and if you desire to include it, I can add that the inline check valve at the fresh water inlet serves to maintain pressure in the manifold when the green ball valve is in the open position for any features that involve the pump.  

Also, if you look at the replacement parts list for the P3, it describes the red valve as a single diverter and the blue/white valves as a dual diverter.   The term “dual diverter” threw me off.  I found by reviewing images of the parts at https://www.rvlocksandmore.com/Dual-Diverter-Valve-Valve-Only
 that the blue/white valves are part of a single subassembly, hence the label Dual Diverter.  My initial concern was that the actual operation of each valve, the blue and the white independent of one another, was somehow different than the Red because the part description was different.  And since I am not from planet Krypton and lack X-ray vision, I wanted to be certain of what was inside that black plastic when I made my marked up pics.

I am looking forward to your finished image(s).  Thanks for the contribution to the forum.

Sharon_is_SAM

Thank you @MuttonChops!  Your PDF file above also helps us understand the Nautilus.

Denny16

Yes, a great diagram @MuttonChops. As you pointed out diverter valves are a bit more involved than simple tap valves.  They can take a single source and switch it to several destination, like City water to holding tank, or RV trailer water systems (sink taps, shower, etc).  They can switch several sources to a single output, like water tank and City water sources to trailer water plumbing runs, and so on.  A single diverter Valce can replace two or three conventional valves in a typical manifold distribution system, like in a lawn sprinkler system.
 Cheers 

Snoblett

Hi all, I have an update.  My camper had been at a repair place somethings- fixed somethings not fixed. I guess that’s how it goes with supply chain issues.

Anyway, my pump had developed quite a bad leak and I think it had a substantial leak from day one because of how my hot and cold water has been spurting from the very beginning.

They did fix the leaks in the lines.  apparently there were several locations that just needed to be tightened or whatever.  

So I’m sitting in my camper today and I decided I would dewinterize it and flush lines and test everything, because I can’t wait all winter long to know whether or not this hot water issue is resolved.

So here’s the deal, I have concluded that when a loss of pressure occurs hot water backflows from the Aldie through the supply line to the Aldie that is from the manifold of the Nautilis. (@d@Denny16  hypothesized this somewhere in this thread) Referencing the installation instructions manual, not the user manual, the installation instructions, to be specific the Aldie backflows through line F which then backflows into line G of the Nautilis, and G supplies all the cold water to the cold water fixtures. This occurs under a loss of pressure.

I was able to determine this because I thought I had put enough water in my holding tank and set everything to dry camping. I thought everything was fixed, and then the pump sounded like an airplane going overhead where it was really working hard, and then the water started going in the other direction and I was re-experiencing the scalding hot water that comes directly from the Aldie through the cold water line without having gone through the mixer.

I am pleased to report that, with sufficient water in my fresh holding tank, I have now achieved pressure with the pump, and that the hot and cold is working as expected.

So, when searching through the threads of 2021 tab 400s with hot water coming through the cold lines, it appears there have been two different problems. Some folks had bad mixer valves for the Aldie and had water flowing through there. In my case my pump wouldn’t hold pressure, and when that happens, hot water that’s pressurized in the Aldie will backflow to the cold water lines directly

Snoblett

My final thought on this is wondering why there is not check valve in place on the line that is the water inlet for the Alde.  This would be line F when referencing the Nautilus Installation instructions.

Ill ask folks to opine here, but I do intend to ask this question of both NuCamp and Alde.  In my mind, there is a safety issue here because the water that comes out of the Alde is truly scalding, hence the reason for directing hot water from the Alde into a mixing valve under normal circumstances.  I would think that preventing hot water flow back to the Nautilus would be a requirement.  And, since there is a pressure safety valve already on the hot line between the Alde Flow and the Alde Boiler, I should think the pressure blow out aspect is covered.

Let me know your thoughts on having an inline check valve installed prior to the Alde inlet on line F out from the Nautilus.

thanks all!!

[Deleted User]

Hi Snoblett, great detective work here from all contributors. How fast can you suggest this to NuCamp? Mine is scheduled to be built this month! 

Snoblett

@TabbyShack I just sent an email to NuCamp. I’ll keep you updated!

bergger

Just curious if people who have experienced this hot water problem in the cold lines all have the new mixing valve or has it also occurred with anyone that has the older mixing valve?

Snoblett

bergger said:

Just curious if people who have experienced this hot water problem in the cold lines all have the new mixing valve or has it also occurred with anyone that has the older mixing valve?

For me, the mixing valve is not an issue. 

As soon as I experienced loss of pressure, water back flowed from the Alde to the Nautilus.  The mixer was not involved.  I’m tact, when I am on city water where pressure is consistent, I do not experience any backflow.

I am aware that there are folks with mixers that have flow issues with hot and cold.

Denny16

I have not experienced any hot water back flow with the old mixer on our TaB400, but agin, we do not have the Nautilus system either.  When it first came out, I thought this was a great idea, and carefully followed the disc as worked out how it worked.  Then when the issues started appearing, kind of glad I do not have the Nautilus setup.  The 2018/2019 per Nautilus TaB400s had a fairly simple water setup.
 Cheers 

MuttonChops

= + = Nautilus P3 Water Flow Overview = + =

An updated version 2 of my earlier  Water Flow Schematics and a new set of 3D images is in the attached PDF file.

@Snoblett and @Denny16 provided multiple draft reviews and content support.

It is hoped this document will provide all interested members with an easy to understand visual schematic for water flow paths at the different Nautilus handle positions.

Additional information and images in the document could be helpful for anyone starting to troubleshoot, repair, or modify the Nautilus "backside plumbing".

Snoblett

Kudos @MuttonChops!!!
Very, very nice work.  I found it helpful while getting through my issue that I just completed. ☺️

jkjenn

Sharon_is_SAM said:

@jkjenn - how are you maintaining the Alde air cushion with lengthy excursions?  Are you accessing the Alde tank drain valve at intervals or do you drain the tank and then refill?

I don't do anything special. I imagine that I am emptying and refilling enough to do that, naturally.

Snoblett

Denny16 said:

“Denny16  “ Snoblett has a 2021 with Nautilus and it only has 1 hot and 1 cold low point drain.  The Alde drains via the cold line.

I guess you don’t really need to bypass the Alde - just open a faucet and drain some water via the low point drain!  Just make sure the pump is off and the city water is turned off!” 

@D@Denny16
sometimes it takes time for things to percolate through my brain.  Your statement above, “The Alde drains via the cold line,” should have been my ah-ha moment regarding the back flow of hot water directly from the Aldi into the cold line when a loss of pressure occurs.

Eventually, and after understanding the flow sequences of the Nautilus it became clear to me how this could occur.

Now, I have put in a message to NuCamp that is being considered by R&D to have a check valve installed somewhere on the line to the Alde from the Nautilus (line F when referencing the Nautilus Installation Instructions).

But, if this comes to fruition that a check valve be installed, then the parallel conversation in this thread regarding the refresh of the Alde air cushion changes and would necessitate the opening if the bed to access the yellow safety valve.

The whole reason that the method of using a low point drain works (I think), is because of the allowed back flow of hot water into the cold lines.

Do you concur? Is my thinking correct?

Denny16

You typically open the low point drain, whilst the water system is not pressurized, so hot water just drains out through the low point drain, and not back up the cold water lines (path of least resistance concept).  

The only was I see hot water backing up through cold water side of the system, is when the cold water pressure is lower than the hot water pressure, or no pressure in the cold water side of the system.  

If the water system is pressurized, then hot and cold water would both run out the low point drain, which would drain water from the water tank, if on Dry Camping mode.  So I would shut off the water pump to use the low point drain to burp the Alde hot water tank.  If on City Water mode, switch to Dry mode and release the water pressure from the Alde with the low point drain.  In this case a little water might backup the cold water side, until pressure equalized (faucets turned off) and hot water would still drain out.  If the cold water faucet was on, then hot water could run out the faucet also, as there is no other water pressure (pump off) feeding the cold water side.

I hope this helps.
cheers

Snoblett

For those interested, this is my novice level, hand drawn flow diagram of just the Hot/Cold water subsystem of a Tab 400 with a Nautilus P3.   It does show where the proposed check valve will be installed when I receive it from B&B Moulders

Denny16

@Snoblett, I see now what you are talking about,  Have a look at the first diagram in this flow chart: https://us.v-cdn.net/5021717/uploads/editor/03/9dairdbcztfd.pdf

It shows the Alde Bypass connection, which aside from the A
de mixing valve, is the only point how and cold water lines can cross over, allowing hot water to your cold water lines.  If the Bypass valve is defective, it could allow hat water to flow back in cold water pipes.  A check valve at this point, per your suggestion, would be a good safety measure in case of a valve failure in the Nautilus system or Alde Bypass valve. 

You should have your Alde Bypass Valve checked when you take the TaB in to have the Nautilus checked.  Good luck.
cheers

Snoblett

@Denny16
can you resend the link above?  It brings me to something titled “Selling the following Micro Studio Camera Kit and accessories:”
Thanks!

Denny16

@Sob. Sorry, wrong link, I placed the correct link in the post.
Here it is: https://us.v-cdn.net/5021717/uploads/editor/03/9dairdbcztfd.pdf