# roof mounted water tank for gravity fed shower ??



## jezjay (Feb 11, 2011)

Hi All.. 

Has anyone got any info on fitting a large flatish ( 290mm ) water tank on the roof to service a shower below ? we don`t need the water to be heated as main use will be summer time and tank will be black so will heat naturally during the daylight sunshine.. ( the tank will be UV proof strength wise etc..)
It will be easy to secure etc and I can fill with hose etc.. but not sure on how the gravity thing will work ? Is there a specific valve ? Obviously need to vent tank somehow to realease air to consequently create water flow... 

Anyone got any ideas ? opinions  ? negatives ? positives on this ? 

thanks in advance

Jez


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## frogdude (Feb 11, 2011)

Sounds like a good idea to me. The gravity thing works fine for those solar showers, but yeah you will probably need a way for air to get in. How high would it be? Practical to loosen the filler cap when you want to use it? Or maybe incorporate a one-way valve. Different sized valves might possibly affect how fast your water flows out (could be a bonus). Maybe there's an adjustable type....

ETA. Just had a browse on ebay, one way valves for aquarium use are very cheap. Just drill a 4mm hole in the tank, insert valve, and gorilla-glue it in place. I'd put it on the side of the tank, near the top. Air can get in, water cant get out. That's how this cowboy would do it anyway...


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## Beemer (Feb 11, 2011)

jezjay said:


> Hi All..
> 
> water tank on the roof to service a shower below ?   negatives ?



I can think of one negative ...the weight on the roof in relation to the vehicle handling when driven.
I wonder if anyone has used this idea before?


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## jezjay (Feb 11, 2011)

It`s going on the roof of a Merc Vario with a shower/ wetroom directly underneath, so getting to realease cap would be difficult.. some pressure would be good as also for rinsing wetsuits and sandy spaniel !!

I`ll look into the valve thing.. I`m sure there must be something, 

the tank will hold upto 175 litres If necessary. (don`t worry bout weight as 7.5 tonner )


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## jezjay (Feb 11, 2011)

The tank is very flat only 290mm  by about 1000 x 600 and will be fitted to a large flat roof cage so won`t be sitting directly on the roof..


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## Kontiki (Feb 11, 2011)

Thought about the idea of having some sort of solar heater for the water on the roof, this coupled with an insulated tank. It would need some sort of system to sense if the water in the tank would be cooler than the water on the roof, this way it could operate a pump until the water in the tank was hotter. The pump could be operated by solar power as well. There are lots of sites showing how to make a solar heater from soda cans, heres one SODA CAN SOLAR HEATER


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## jezjay (Feb 11, 2011)

Heatings not really a problem as like I said will be mainly for summer use and with quality tanks painted black I think they`ll retain their heat enough for our purposes.. It`s the water flow I`m kinda stuck on at the mo... 

Would it be difficult to set a pump system up ?? or maybe that defeats the object of being simple.. ( we will have small pump for kitchen sink etc from seperate tank )


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## Deleted member 207 (Feb 12, 2011)

Lash out a few quid on a solar camping shower bladder - about a 15litre black plastic bladder which will have all the fittings - hose, tap, shower rose. Use these to make your shower.

Filling maybe an issue up so high - need for a ladder, always a hose, etc.

Even on a 7.5 tonner 200kgs up at the highest point of the vehicle will have an effect on handling - when its half full it will be even worse as the weight/water will slosh around unhindered. 

Low down fitting you can use a watering can to fill when a hose cant reach. The centre of gravity is kept low. Fuel consumption wont be affected either.

With so many under chassis tanks available - have a look at caravans - it may be a lot easier to find and fit a tank low down and then use a 12V pump to put the water where you want it.

You can wrap some copper tubing around the exhaust manifold to get heat - there might even be kits still around for that type of camp shower from the likes of ARB dealers in the UK.

On a 4x4 I used to own we used 100/150?mm plastic water pipes as a tank with end caps and U joints and fitted that under the table top. Very easy way to build a custom shaped tank to fit in odd shaped places.


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## Tbear (Feb 12, 2011)

Jezjay,

I am with Roger, a kg of water moving from one side of the van to the other has velocity which makes it weigh more and when you corner its moving in the wrong direction. Because its a couple of meters in the air it becomes a weight on the end of a lever as well. It would take someone a lot cleverer than me to work it all out but I am sure the affect would be considerable if you where to swerve.
You would need to raise the tank well above the top of the van to give you enough water pressure for a good shower rather than a trickle or have a pump. You can get low power 12V showers cheaply.
I got to say I would only have the tank on the roof when parked. Could be well worth it if you are parked for a few days. Put the tank up there empty and fill with a hose. Safe, secure and loads of free hot water.

Sorry I could not be more positive

Richard


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## jezjay (Feb 12, 2011)

Hi Richard and Roger.. Yep I hear what your saying and think your probably right.. I`ll look into the low tank pump option .. 

Any recommendations of tank size for this ? can it service both shower and sink ? which pump is best ? 

Sorry for all the questions.. Its our first conversion of this scale and want to get it right... we`re not to fussed on budget.. as the vans gonna be a "keeper" and is worth spending money on..

My idea of the gravity thing seemed a good one at the time !!

Cheers for all your input


Jez


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## AndyC (Feb 12, 2011)

As others have said, a roof mounted tank is a bad idea unless you only have water in it when you are stationary.

We have a Vario 814 LWB, what length have you got? The Vario is wide enough to have a bed over 6ft long across the van. In fact that's what we have in ours, a permanent double across the back with a 150l water tank under it. With the tank and the pipework all inside we don't have to worry about it freezing in the winter. Pump is a ShurFlo 30psi 10l/min one

Our hot water comes from a calorifier, (this one: 22 Litre Surecal Calorifier calorifiers water heater on eBay (end time 13-Mar-11 13:38:54 GMT)) heated directly from the engine and also from a Webasto Thermo 90. The company that makes the calorifier is very helpful with advice on installation. The beauty of it is that after a few hours drive we have a tankful of free hot water. It has an immersion heater (1kw) which we use if we get a hookup, or we can run the Webasto to heat the tank if necessary.

Some pics of our van before we bought it, in Belgium: Vario 814

PS: The Thermo 90 was already fitted when we bought the van but I added the calorifier. Given the choice now I think I  would go for the Webasto Dualtop instead.

AndyC


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## Tbear (Feb 12, 2011)

Jezjay,
I am sure someone will come up with a tank you can pump water into to heat and drain surplus back to the main tank before moving so don't be disheartened.
In the meantime have a look at  CAK Tanks | Premier Source Of Interior Equipment | Motor-Caravan | Caravan & Marine for the tank for your vehicle. Not sure about the pump but I am sure someone else will help with that.
Richard


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## frogdude (Feb 12, 2011)

There is a camping shower available with a submersible pump on one end of a hose and a shower head on the other. It's designed to be used in a bucket or bowl of water, and plugged into a 12v supply. I'm sure it would be easy to adapt for use with a semi-permanent water tank. I'll have a look and see if i can find what i'm talking about.


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## frogdude (Feb 12, 2011)

ebay item number: 200540726697 £19.95 with free delivery.

Or this  Outdoor Megastore Reliance On-Tap Shower Unit


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## jezjay (Feb 12, 2011)

Thanks again for the info guys.. I`m doing my research !!

Andy sent you a pm..

Cheers

Jez


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## Deleted member 207 (Feb 13, 2011)

Whale make submersible pumps, simplest way to go.

Shurflo and Flojet are other makers with varying degrees of sophistication from pressure sensing systems to simple tap operated 12V systems. (sophistication = impossible to repair)

Exterior mounted tanks do have some downsides in the winter months - freezing being the main one so need to be fully drained including the pump - travelling with full tanks in the winter can be a problem as they can freeze.

Interior tanks mounted under a bed or seat are well protected from freezing and are easy to plumb in without having to drill holes for power and hoses to re-enter the interior, just one hole for the filling nozzle.

Water heaters - Truma, Suburban, Eberspacher (hot water and central heating), REZI 240V instant hot water services. Plenty of others.


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## Deleted member 5759 (Feb 16, 2011)

I would definately not advise a roof mounted tank although the idea is a good one as regards gravity and solar heating.

A half empty unbaffled tank with 100 odd litres of water sloshing about on the top of the van is going to seriously affect the vans stability on cornering.

There are loads of bits for installing a water system including a 70 litre tank, pumps, showers, hoses etc etc here Caravan & Motorhome Water Pumps, Taps, Tanks, Filters, Hoses, Carriers to give you ideas.

Good luck

Peter


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