2021 320 Water Tank connections

Maxcamp8

Anyone have pics of a 2021 320 after removing the Coroplast belly cover? 
Like to identify all the Fresh Water Tank connections positively prior to undertaking this task.

Need to rework the main tank drain and hopefully upsize it.
Older pics show a maybe 1" threaded bulkhead into the tank bottom, reduced to 1/2" Pex.  Like to maintain the 1" diameter out to a new drain.

Ready to modify the tank connections and drain outlet diameter so I don't spend an entire day each time I sanitize and flush.  Many...days....now.
1. Significant tank sags in front of axle support, traps several gallons of antifreeze/bad water/chlorinated sanitizing water.  Tilting trailer way way way up does not overcome.
2. Puny 3/8" outlet drain takes an entire day to drain at full speed, with all taps open.  Compressed air introduced elsewhere does not speed up the process.
3.  Burnt out and replaced one pump early on, as the only way to flush the tank out is to pump entire contents up through faucet over an hour plus, rather than spending 10-12 hours watching it pee out the tiny outlet.
4. Nucamp installed supports for round tanks on this square tank.  They touch at two corners and sag 4" below tank, basically useless.  The half I've seen is only held up by the axle.

I found some helpful older photos here, but would like to see if there are changes for 2021

https://tab-rv.vanillacommunity.com/discussion/7410/draining-fresh-water-tank

https://tab-rv.vanillacommunity.com/discussion/comment/198287#Comment_198287

I have a photo of existing condition here:

https://tab-rv.vanillacommunity.com/discussion/comment/199564#Comment_199564

Sharon_is_SAM

@Maxcamp8 - I have not seen a photo, but, I do know that starting with the 2021 model, the fresh tank drain comes off the rear, rather than the front of the tank.

cid69

Maxcamp8, a T@B newbie here but longtime rver. Wouldn’t it be simpler to solve tank drainage issue by putting a new separate drain in the tank bottom with diameter and place of your choosing? On my old 5th wheel the water drain was 2” diameter.

Maxcamp8

@cid69, good suggestion.  I cannot access tank interior to install a Bulkhead fitting (screw threads inside) but there is a fitting called Uniseal, push-on from outside and push pipe through i.d.  I suppose I could mount a 2" dump valve and strap the valve to the tank to minimize vibration/shaking of the Uniseal during travel.  Researching further.   

I wonder if I could cut a 6x6" handhole, install a bulkhead, and close up with a 8x8 flexible patch glued from inside and screwed through.  I would need Nucamp to specify the tank material and thickness so I can dummy test process on something else first.

@Sharon_is_SAM, thank you.  Yes no connections seen from front.  Will have to drop rear of belly cover.

What can I say to Nucamp to motivate them to install a proper drain, rather my DIY?

cid69

https://m.youtube.com/watch?v=rHctfQ4264o  ???

GregChris

I've had 3 rv/towables, they all have had the same fresh water drain stop cock. Most things on nucamp trailers are industry standard construction, plumbing, electrical, etc. The only places they differ are the Alde and air conditioning. And those are standard in Europe. At least that my understanding of things.

Mickerly

A two inch drain line for 10 gallons sounds a little large. How fast do you need to empty the fresh tank?

Maxcamp8

Here's what I came up with in a hurry before rain today.  
Dealing with Nucamp snapped and stripped s.m. screws took hours.

Drains a full tank in 20 minutes rather than 3-4 hours.   Now we can weatherize midtrip and flush out RV antifreeze without spending a whole day.  Still need to jack front of trailer way up to get last gallons.
Still airlocks unless open a faucet; I don't see a second tank connection anywhere, front or back!  Unless there's a tank connection up through the floor it appears all water in and out of tank goes through this one fitting?  Not the case on older models.

Photo 1- New fittings below; old at top.  Nucamp uses 1/4" ID pex fittings and 1/4" outlet brass drain valve, restricting flow to a mere dribble on my 2021 camper.  Replaced with Full Port ball valve and threaded 1/2" MIP fittings, tees off the Pex on the right.
The original 1/2" MIP to Pex elbow was loosely threaded and heavily puttied, easily turned by hand.



Photo 2- Final build.  For travel valve lever is horizontal.




Photo 3- Fittings are purposely installed crooked in this photo to enhance lowpoint draining.  Rubber tape used on left.  



Photo 4- Here's the original layout.  Drain is off to right.  Restrictions and uphill runs precluded full drain.
To get last gallons it's necessary to tilt trailer way back using jack.  Then the pex run to drain is uphill and again does not drain!  Full days spent trying to flush antifreeze out of tank via the pump and faucet. 

PHoto 5- With the Coroplast scrim back on and hose fitting hooked up.   Blue handled BV is on the overflow drain; close to keep out bugs and to pressurize with compressed air for enhanced draining prior to this mod.

stepheng

Did you add any additional support for the tank?  Do you think that should be added?

Maxcamp8

Our tank was poorly installed in factory, resting midway on the axle and with two misfit **half round** brackets at ends rather than appropriate rectangular brackets.  They do support just the bottom rank corners.  After two years of severe bumpy roads and concrete  highway joints bashing I don't see signs of any anchor or tank failure.  Our issue was complete inability to drain, which we rectified.

manyman297

Those supports are wild. How did that even pass QC (if there actually is QC)? Glad your tank is holding up. I'd be worried about the corners of the tank gradually digging into the straps but it sounds like you're good. 

Maxcamp8

Interesting result.  After replacing the Nucamp threaded outlet from the water tank, our water pump is holding its prime during moves for the first time ever.  Nucamp loosely threaded this fitting, with pipe dope.  I surmise a bit of air would leak in during bumps and compromise the suction side of the pump.