Exterior Optional 3rd tank operation

F

Fallen

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Feb 7, 2019
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Hi all,

Trying to work out exactly how my optional 3rd water tank works on my 2015 20.64-1 OB. I can only see one valve on it at the bottom, presumably to isolate it from feeding the van.

Does the 3rd tank fill up only when the 2nd tank is full, or does it fill in parallel with the 2nd tank. And if the bottom valve on the 3rd tank is open, does the van take water from the 2nd and 3rd tanks roughly evenly?
 
M

Macca_75

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Aug 3, 2016
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I have a 2016. Underneath there is a little tap with 3 hoses connected. In 1 position it points to the front 2 tanks, when turned around it connects to the third (rear) tank.

You need to manually "switch" from the front pair to the rear.

As for filling, all 3 have separate fill points (each of the fill points can house 2 tanke). As the front 2 are connected they eventually level each other out anyway if the tap is set to the front - it it's set to the rear I need to fill each independently.

The rear has it's own fill point.

Hope this helps - I can't get any photo's as the van is currently in storage
 
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Fallen

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Feb 7, 2019
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Interesting. I only have 2 fill points. And my tank configuration is the two standard tanks on each side of the axles, and the optional 3rd tank behind the back one (so two tanks parallel at the back).

Pretty sure my switch does the front tank in one position and both the rear tanks on the 2nd position.
 
Drover

Drover

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Follow the hoses and throw us some pics................. its the only way to find out about the set up really.....
 
F

Fallen

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Feb 7, 2019
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Def not grey water. Got pics today. Photos show 2nd (standard) tank (plate protection) and 3rd (no plate protection). 3rd is connected to fill/outlet of 2nd at the base via smaller diameter hose, with an isolation valve. Top breather is connected to the breather line of the 2nd.
 

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M

Macca_75

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Is this after factory installation? My 3 tanks (from Jayco at build time) all run east/west. 1 and 2 are in front of the wheels, 3rd is behind. All have a stone guard as well.
 
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Fallen

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Feb 7, 2019
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As far as I know it is, but might not be as we bought it 4 years old. Van is a 2015 20.64-1
The 3rd rear tank can't go east/west as the underslung spare (definitely factory) is in the way.
 
M

Macca_75

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Aug 3, 2016
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I didn't think the spares were underslung as default. Anyway, there is also no stoneguard.

Either way just draw the plumbing out with all taps and junctions and you should be able to figure out how to operate the tanks pretty easily.
 
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Drover

Drover

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I would say it was done afterwards possibly even at the dealers, looks like it could fill from the other tank, I would just redo the plumbing so it works your way and can be got at without crawling under the thing........no need for any special pipes really as its all no pressure off tanks, I just use clear PVC from Bunnings and Pope garden fittings.
 
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Red1

Red1

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Sep 14, 2013
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We have a 2015 20.64 with 3 factory tanks. We have 3 separate fill points. There is a small 3 way valve under the side of the van, in the usual place, to select which tank you want to use. Each have individual level gauges as well.
 
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Fallen

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Feb 7, 2019
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OK so highly likely post production tank as mine doesn't have monitoring either. But I've had a good look at the piping this trip and it appears to be a pretty common Primary/Secondary tank setup with breathers and fillers connected, all at the same level, so will level out pretty well. Might just need to slow fill to ensure it fills up.
 
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Fallen

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Can anyone think of any issues if I shorten the breathers for both rear tanks? I'm getting water in the breather lines (tried to route them better but still an issue) and particularly when filling, the breather line between the two rear tanks (which is connected together) gets blocked meaning the 3rd tank can't breath and doesn't fill.

I'm thinking of just cutting the breathers on the back tanks as short as possible and putting fine mesh over them, so any overfilling will just flow back into the tank. Issues with this?
 
Drover

Drover

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Big Mal had a single tank fill and breather for 2 tanks, so when you filled you got spat at all the time, I fitted individual fill points and breathers for both tanks which solved the problem, it also allowed me to use one tank at a time instead of when I had emptied one tank the other was half full, fill point is halfway up side of tank..........................
In your case yep I would run seperate breathers for your tanks but the ends must be high otherwise you will bleed water when on slope (like going up/down hill or around bends) and stick a mesh filter over the end............... I never like 2 tanks that fill and drain in unison just bad design and if one breaks, thats it your done .
 
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