Nautilus P3 Flow Diagram

Snoblett

Hi all,
I am wrapping my head around wizardry inside the Nautilus P3 manifold.  I am wondering if anyone has any Flow Diagrams to help unravel the mystery.

I am currently using the User Manual and the Installation Instructions as reference materials. 

https://www.bandbmolders.com/index.php/p3-2/

Thanks All!

[Deleted User]

I would like to see that too. I'm the type who wants to understand what the levers do and not content to just follow the diagram. This is the reason I really prefer my old school open design on my 2019, but I have a 22 on order so I had already been thinking I was going to need to get a look behind there to see what does what. 

Sharon_is_SAM

This may help.  Compliments of TomCanada.  It is located under Owners Manuals - Winterizing.

https://us.v-cdn.net/5021717/uploads/editor/vs/8g0vm09wvtc8.bmp

Snoblett

Here’s a start of what I’m working on doing:

The purple arrows and text describe the flow of the liquid given the positioning of the knobs.  I have colored squares matching the colored valve knobs on the outside.  The slash in the box indicates the positioning of the valve for the T’s or the inline one is the Green.

Snoblett

The reason I’m doing all this is that I suspect I may have a faulty nautilus.  Everything works great until I put it in Dry Camping mode.  The pump runs continuously and sucks the hot water back OUT from the Alde and back feeds into the cold water supply of the nautilus , labeled as letter F.  

This creates the situation where my hot water runs almost dry at the spigots and purely, hot scalding water is running through my cold lines into my cold spigots.  This includes the toilet.  Scalding hot water flushing the toilet.

my repair guy hasn’t been able to wrap his head around this and is attempting to suggest that the ambient heat due to being in a tight space under the bed is causing the cold lines to “warm up”

There are a lot of points I could make as to why his assertion is flat out wrong, but I’ll leave it at understanding the specific heat value of water to posit his assertion as ludicrous.

Snoblett

TomCanada’s schematic is a great high level schematic for understanding the knobs in the Alde.  I would not add that there is another component related to the Alde that is not in his diagram, it’s inconsequential to the goal of his diagram so no big deal.   

Exterior to the Alde is a mixing valve / temperature regulator.  It is considered to be part of the overall Alde system.  It’s called the Thermostatic Mixing Valve.  This is not to be confuse with any mixers that are integrated with the spigots at the sinks or showers.

The hot water line coming out of the Alde tank goes directly into this T shaped mixer.  Similarly, there is a cold water input to this mixer.  The bottom of the T is the combined (mixed) hot and cold water.  All of the red pex lines that feed the spigots originate from the Theemostatic mixer output.  This sets the maximum temperature of what your hot water can be when you use the sink.

I suspect that they needed this because the Alde is also used for heating the camper.  The default temperature for heating the Alde fluid is probably higher than what you’d want fit safe hot water.

BridgerSunset

@Snoblett We experienced scalding water at the toilet this year as well in our 2021 400 Boondock.  (Wife made it clear that it wasn't a joke .....).   

We only got to use the camper enough to heat water only a few times this past summer; and we noticed it was scalding at least twice.   We never could pin down the reason.   Didn't really try to see if the shower/sink was also scalding, since the cold water line which feeds the toilet also feeds them.  The lines appear to be correctly plumbed into the mixing valve (I sent pix in to Nucamp) and into the bath.  When I discussed with Nucamp, they could only offer that they suspect that mixing valve is allowing backflow of hot water into that cold water feed line.

Rather than simply send me a new mixing valve to put in, they require us to have it diagnosed by our dealer, which involves 2 separate round trips of 330 miles each.   As this directive hit about the time we winterized, we nixed that work until next spring.  

Maybe your techs will figure it out before mine get a shot.  Good luck.

Snoblett

@BridgerSunset
intetesting….
tech support said the same thing to me about the theory of the mixing valve.

my Thoughts are that the problem lies with one of the nautilus valves leaking internally.

Question for you…when this happened to you , does your pump run continuously, too?

MuttonChops

Well I just had to try diagramming the Nautilus P3 Water Flow.
The more diagram styles the better for communicating information, right?

WARNING: Edit 12/01/21
While doing 3D modeling it appears there is only One hose/pipe connection to the Fresh Water Tank.  Version 1 of attached document shows two.

Updated diagrams posted later in this thread. Dec-06-21

BridgerSunset

Haven't caught pump running continuously, no.  Not 100% sure, but I think the hot toilet might have happened on city water pressure as well, or maybe each time for that matter. 

Unfortunately didn't have time to replicate the scenario before winter hit, and just haven't possessed it long enough to talk sensibly about the Nautilus plumbing yet.

If you note the mix valve in the pic below, it may be possible that the topmost line (presumably the cold inlet line) is flowing backwards, causing hot water to feed back into the cold system, if the mix valve is indeed corrupt.

Sharon_is_SAM

There have been several mixing valve failures reported on the forum.  I would start there first.

Snoblett

For anyone interested, this images show all the configurations of the Nautilus settings.  This shows the manifold on the back side of the Nautilus.  It provides directional flow of fluid through the manifold for each configuration.

I think I’ve combed through and fixed any mistakes, but if you see one please tell me so I can make corrections.  

I’ll add these to the user manuals sub folder soon.  The initial screen shot was taken from the Installation Manual at this link https://www.bandbmolders.com/wp-content/uploads/2019/10/Nautilus-P3Installation-1.pdf

qhumberd

You guys lost me at "Start Here". So for those of us with older models, what are the advantages of this Nautilus system? I think I am seeing some of the disadvantages compared to just following a plumbing line.

Sharon_is_SAM

One advantage is that you can add antifreeze to winterize the lines very easily by using the pump siphon.  It avoids getting AF into the fresh water tank.  You can also do this in the non-Nautilus system by adding AF via the inlet side of the water pump.   The other advantage is that you don’t need to access any valves beyond the Nautilus panel.  A novice can master the system without understanding how the plumbing actually works, simply by placing the handles to a prescribed setting.

A disadvantage is the only way to add water to the tank is via the siphon pump.  If the pump fails, you are out of luck.

Snoblett

@qhumberd
I would echo what sharon_is_Sam said.  The pickle I am in of understanding the inner workings of the manifold is probably unusual.  Operating the plumbing in the different modes is truly a cinch.  Just follow the color coded pictures on the front side and turn the knobs.

The markups that I did were because I wanted to have a precise visualization of exactly where all the liquid is and why on the back side of the Nautilus.  The picture looks like a jumbled and tangled mass of black, white, red and blue Pex 

@Sharon_is_SAM :  regarding the disadvantage of not being able to add water to the holding tank, I agree, and I think that it can be easily modified if someone really wanted to have access.   The Pex line in/out of the fresh holding tank runs on the floor and is easily identifiable.  My guess is that the Pex could be easily tap into it with some sort of fixture that allows you to pour water in.  

The other thing that might work is gravity siphoning via a non functional pump.  My pump was not working properly when I winterized.  It turned on, but it wouldn’t pressurize . I had a 5 gallon bucket up on a table higher than the inside floor height of the camper,   I started the siphon with a funnel and filling the hose, then plunged the hose into the bucket.  Gravity and what little pump action I had got the job done

Sharon_is_SAM

I wonder if you can siphon to the outlet side of the pump?  I guess in a pinch that might work, but lifting the bed would be a pain.

Snoblett

Sharon_is_SAM said:

I wonder if you can siphon to the outlet side of the pump?  I guess in a pinch that might work, but lifting the bed would be a pain.

You said out loud the part we all keep quiet. 🤣🤣😂😂

“but lifting the bed would be a pain”

Omgosh, it drives me nuts every time I lift the head of the bed off!!! 

I really wish they had an access door on the outside adjacent to the nautilus so as to have access to that area.

Snoblett

@Sharon_is_SAM

It just occurred to me that setting the Nautilus to Power Fill Tank (city water to tank), a gravity siphon should be able to be easily established.  It completely bypasses the pump loop.   I guess I’ll have to try that just fir fun one of these days.

Sharon_is_SAM

Yes, and I should have said siphon to the fresh tank outlet.

Denny16

Interesting discussion, when the Nautilus first came out, I thought it a grand idea.  That said, with some of the subsequent issues with it, not so sure anymore.  The simple system used on the TaB400 prior, works fine, and has fewer valves to go wrong.

As for the hot water ending up in cold water lines, as mentioned this is down to the Alde hot water mixing valve.  This is not a bad Nautilus valve or setting, as the only control the Nautilus has over hot water is the red handle Alde cutoff valve, which sends cold water to the Alde boiler in normal position, or bypasses the boiler and sends the cold water back round to the hot water line connection after the boiler.   There is the hot water feed to the outside shower module installed on the Nautilus panel, but this is not part of the Nautilus manifold system, which just controls cold water flow from several sources.

If you are getting hot water in your cold water lines, check the Alde hot water mixing valve…
cheers

[Deleted User]

I'm not a fan of the nautilus, but I will just have to accept its limitations and it will probably grow on me. With the old set up, It only takes the most basic possible understanding of plumbing.....blue is cold water,  red is hot water,  parallel valve means open, perpendicular is closed.  I loved being able to open the access panel on my 2019 400 and be able to see and touch everything.  

I sleep with about 12" of extra mattress on the bed so getting access under there is going to be a monumental task!  I'm going to have to get used to not being able to flip the yellow Alde valves until I winterize every year. 

Denny16

Tabby, you do not have to flip the yellow valve handles to drain the Alde hot water/Flo tanks, as the Low Point drains will also drain the Alde system.
cheers

[Deleted User]

Thanks Denny. I know I read that on another post and had decided to accept that as true. It's just hard to let go of my OCD habits! Haha. Thanks for the reminder that is no longer necessary. 

Snoblett

Denny16 said:

Tabby, you do not have to flip the yellow valve handles to drain the Alde hot water/Flo tanks, as the Low Point drains will also drain the Alde system.
cheers

I’m glad for the confirmation as well.  It seemed absurd that you’d have to take apart the bed every time you want to open drain from the Alde.  Somewhere in the instructions it says to refresh the air cushion every 10 days or if it’s been a while since you’ve used the camper.

The idea of using a low point drain works for me!!!!

Sharon_is_SAM

(Edit - see next comment below this.)

@Snoblett - to maintain the air cushion you can either use the yellow Alde valve or if continuously camping using water, bypass the Alde and drain the tank.  Then refill the tank and remove the bypass.  Air cushion restored.

Snoblett

@Sharon_is_SAM
Thank you! I’m sorry if this is a dumb question as I am truly learning everything all at once, 

ok, so to do as you mentioned, I would change the red handle and bypass water to the Alde .

next, I’d use the low point drain to empty the Alde.

Lastly, put red hand back so Alde is no longer bypassed and the tank will refill itself accordingly?

Sharon_is_SAM

@Snoblett - Actually that won’t work because the Alde drain valve is part of the same line as the cold water low point drain.  But, you can bypass the Alde, then open a hot faucet.  The non-return valve on the Alde hot water line should allow air into the tank enough to drain some of the tank.  You don’t need to completely empty the tank.  Just drain enough to let some air enter and restore the air cushion.  I think it would work best if the Alde tank was hot and under a little pressure.  Then return the red handle to vertical.

Denny16

Yes, Sharon nailed this one, you do not need to completely drain the Alde water tank to restore the air cushion, just use the middle red/hot water low point drain. On the older TaB 400s, there are two red hot water low point drains, one is formthe hot water lines, the second is for the Alde/Flo water tanks.  On my 2018 TaB400 the middle low point drain (red) is the Alde tank.
 Cheers 

Sharon_is_SAM

@Denny - 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!  That seems too easy, but since the Alde is so close to the drain, it may lose some water first before the remainder of the plumbing lines drain.

jkjenn

The Nautilus is one of my favorite upgrades:

Easy to fill the freshwater tank with a jug via the pump.
Winterizing is a breeze!
The cable and TV connections make it really easy to connect to, and the unused connection provides an easy connection for my cell phone booster.

I made the mistake of having the valves set incorrectly once and the water was scalding. I only made that mistake once. Don't ask me how I had them set because it was months ago and I have slept in the T@b about 60 times since then.

Sharon_is_SAM

@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?