17' Series Grey water tank

Heydon

Member
Mar 2, 2018
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Hi all,
I’ve just fitted a grey water tank to my 17.56-2 for the rare occasion parks are strict.
It’s bolted up beautifully with a bracket/stone guard I’ve had made up but that’s where my success ends.
Having tried to make the Jayco plumbing fit up to the tank I’ve found I can’t get enough fall from the shower to the tank inlet which is 40mm and pretty much against the floor at the top side of the tank. The outlet is 40mm also- I’ve read that I can use that as an inlet as long as the top one vents well. Have anyone had any practical experience with using the lower hole as the inlet? I have a valve and camlock so it can drain straight out the hose if needed.
If going in through the bottom works is there any advantage in connecting the bottom and top inlets (diagonally) with pipe to aid venting and flow? Or is that unnecessary?
Cheers.
 
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Drover

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Nov 7, 2013
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I think I get what you mean, if you plumbed your shower into the outlet you would have to join between shut off valve and tank, you do need the biggest hole possible to drain so you get all the icky bits out, you certainly need a vent preferably lower than your shower drain, then it will act as an overflow, otherwise you will end up with back flow into shower, there are fancy valves you can buy to stop this as well as any smells but if you don't have any drop they will hinder the flow, if you keep the tank flushed smells aren't a problem.........Removing and redoing the original drains usually improves the flow of it all, the twin drain system is just a lazy way of fixing a problem....my GWT while not the same is used all the time, the GW flows thru and out or gets stored when tap shut, that way no stuffing around.

Some pics always help.
 

Heydon

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Mar 2, 2018
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Warrnambool
Thanks mate yes the smell is something I was worried about and I think my trying to fit a P trap inline was causing issues. Not all the issues but definitely exacerbated the lack of fall. We can always put the plug in the shower. I have a couple of plans up my sleeve to try. Both include getting rid of quite a bit of that clear hose Jayco love and replacing it with 40mm pvc. That’s surely a step in the right way regardless.
I could spin the tank around but that means the outlet is then either on the awning side or I have a long pipe back to the other side making hosing the tank out a bit tricky.
What isn’t helping is my van is on gravel and we’ve had torrential rain and gale force winds so getting back under is an unattractive prospect. I’ll snap a few pics when I can and I can make it all work I’ll share how for someone else’s future reference.
 

Crusty181

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Feb 7, 2010
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You can fill the tank from the bottom, that's how filling balanced multiple water tanks are plumbed so they both fill at the same rate, shouldnt be any different in a caravan. You'll obviously need a decent breather

Im not sure a trap would work very because the working space over the height of a water tank and bouncing about driving may just emptied the trap. You can get one way plumbing valves that will stop the smell and back flow.
 
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Drover

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Nov 7, 2013
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With my GW tank I don't have any S, P or other fancy bends they run direct into the tank, never notice any pong and but there is about 75mm drop from shower drain to tank so no chance of back flow, in my 14.44 I plumbed the sinks seperate to the shower drain and it was a short direct run to the tank with very little fall, no pong, no back flow either but my tanks were super easy to flush...... Big Mal does have a one way valve on one of the shower drains and it certainly attracts some gunge but it was there originally, I reckon see how things go the simple way then if needed do more mods.....
I for one favour the clear plastic pipe for drains, I just use black poly joiners with zip ties to hold, way easier and cheaper than PVC pipe which doesn't flex and in time a good rock hit will break it.. I have never had problems with the plastic pipe and it is so easy to mod also or repair if needed with just a knife.
 

Heydon

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Mar 2, 2018
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Warrnambool
Thanks lads that’s handy info particularly regarding smell. It’s hard to fit it all in.
I’m lucky enough to been able to place the tanks where the guards will also protect the pvc pipe, with the flexible stuff outside of that as I haven rhe same opinion as you Drover about stones and flexibility.
One of the options I have is an almost flat run of 40mm pipe for about 120cm. Given the small amount of water coming out of the shower that’s only going to fill maybe the bottom third of the pipe so as long as we’re parked flat it’ll flow into the tank.
This time I’ll try a few things without glueing the fittings. That was a dumb move the first time!
 

Heydon

Member
Mar 2, 2018
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Warrnambool
UPDATE:
I’ve won the battle! Bottom entry works a treat and simplified the whole thing 100%. I’ve seriously used about $20 worth of fittings after wrecking about $30 worth of fittings and it’s spot on. The shower empties better than it ever has.
Drover, you’d be proud- one of the answers was not getting too clever with PVC and sticking to the flexibility of the clear beer-bong hose.
I’ll chuck some photos up with I finish the outlet and clamp everything up.