Off-grid shower - how 2 max the pressure?
Hi All,
We love tiny little CL sites and are happy to survive on just 12v and Gas.
I've been trying to boost the water pressure so we can have a shower and as such I currently run 2 whale pumps together from 2 barrels which feel into the same outlet and it works okay...well...ish! The water comes out the shower head as a nice hot stream rather than a dribble, but I was wondering if we could make it more powerful (well, I wasn't, but my better half has lots of long hair...)
Was looking at a slim submersible industrial 12v pumps tonight which are rated at 30ltrs/min, but just wondering...at what point do we overwhelm the Truma water heater?
Any idea what it's max flow is, or any suggestions? Or would two leisure batteries in parallel provide more umpf?
Any help appreciated
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You have a hot water reservoir/tank so you would simply draw from that (mixed with the cold) until it is gone. It is not an "instant" heater so will take 20 - 30 mins to heat up again once all the hot is gone. The tank may be a maximum of, say, 10 litres but not sure about your system. Assuming a 50/50 mix you would get a 40 second shower with your proposed pump!
I would also be concerned about excessive pressure in the system if you have too big a pump.
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I agree with Hitchglitch.The components of the system in a caravan are not the same as those used for mains water supply in buildings and cannot cope with high pressure.
The fitted pump will have been chosen to match the system's requirements. The flow rate of the onboard water systems is governed by the diameter and routing of the pipe work and all components will have a maximum safe working pressure.
Fitting a more powerful, or higher capacity pump, will probably do little to increase the flow rate but may cause damage to the system and/or leaks. It would also invalidate any warranty on the components of the system.
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I don't know what shower head you are using, but try one of the newer eco ones. The one in my van gives the feel of a fuller spray pattern but injecting air. It does make a difference.
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Nooooooo far too noisy. Solar power to keep it topped up. Just use the navy method of showering. If we are to enjoy pursuing our hobby in more remote areas without house gape plumbing we have to adjust our expecting 😉. Maybe a bucket full of warm water and a jug to rinse long hair. We used it for short hair too when I grew up, not the bucket but a washing up bowl because you do need clean water for rinsing.
Alternatively nip down to the local river or stream for a really refreshing experience 😉 😂.
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A generator wouldn't prevent over pressurisation of the water system.
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OP is talking about basic CLs, possibly without even EHU. What are the chances of a constant water connection, even if only for the duration of showering? It is going to mean a great deal of ferrying fresh water, and maybe even waste water!
(I do understand the problem though, as wife has long hair and gets quite crotchety if she cannot properly wash it for more than a week at the very most!).
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Let me try again. Caravan water systems have small bore pipes not suitable for high pressure feeds. Blast water through the system at high pressure and you risk blowing joints apart and causing untold damage.
The water system is not designed for high pressure but it's not my system so I'm not worried.
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we changed to an Ecocamel shower head a few years ago and its nowbeen in three separate vans....its certainly better than the ones originally fitted.
it mixes air with the watwr to deliver a wider more poweful spray , yet use less water (thats the advertising bumpf).....
id certainly give one a try, perhaps borrow one but watch out for those microbes
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Caravanning or motorhoming has to come with some compromises even though we like to make it as comfortable as possible. My wife always has her hair cut before we go on a long trip!
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Cheers all for taking the time to respond. The reason I doubled up the pumps was on just the one pump the water crawled from the shower head when in its holder at head height - couldn't even manage individual jets from the holes in the shower head, and the original whale pump was supposedly rated at 14lts/min!
Hadn't considered over-loading the pipework as the flow was so feeble! But it'd be easy (for me) to re-plumb everything if required into semi-rigid plastic pipe, but it might be easier to try the Ecocamel shower head first as we now have a sort-of reasonable spray...
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On the subject of replumbing, if the pipework is assessable, check that there are no kinks or tight bends. These will restrict the flow. Try to avoid 90 degree bends. If using tee junctions, keep the line to the shower, through the "flow" of the fitting. Try and keep the use of fittings to the minimum as each one will add flow restriction to the system. Sweeping pipe work will also aid in draining down for winter.
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Our latest van has one of these and I get a jet of water coming out of the air hole rather than air going in.
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As the water flow from the shower has been described as "a dribble" and "crawled" then surely this is indicating a fault with the system or for our type of kit an unrealistic expectation?
Our van has two different pumps, an inboard in-tank submersible and an in Aquaroll submersible, either can be used but the pressure and flow performance are quite different, the in-tank being better.
Plus also if on EHU both work with noticeable more vigour than they do if not on the EHU.
I would be in the OP's case seeking what is wrong with their system; in the past, I found the non return valve in the feed to the boiler caused issues with varying temperatures and flows with the height of handset. Changing the NRV improved things.
With rotodynamic pumps as used in submersibles then placing them in series rather than parallel will add the heads [pressure] and with that increase the shower flow performance. Will require housing the second pump in an in-line container as they are not made to readily use in this way.
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It would be worth the OP measuring the water flow at the shower and the pump to see what difference he is getting a flow rate in lpm would at least give an indication of whether he is being over optimistic in his expectations of he does have a plumbing problem.
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Agree. I put an Ecomel head in mine. What a difference.
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Hi Ocsid
"With rotodynamic pumps as used in submersibles then placing them in series rather than parallel will add the heads [pressure] and with that increase the shower flow performance. Will require housing the second pump in an in-line container as they are not made to readily use in this way."
(Sorry, not mastered the cut n'paste thingy on this site)
I'm guessing you mean if the the one pump feeds the other then the flow rate is increased? If the one pump isn't as powerful as the other, I'm guessing the lower powered pump runs first to feed the more powerful pump?
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It's nice to know I'm not the only one.
It's a puzzle though as the water pressure from the shower head is acceptable and provides a good shower but that would be far better without water escaping from the air hole.
I'm going to our van tomorrow and intend checking if the head can be dismantled for cleaning, if not I shall tape over the hole until I can find a better showerhead.
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if the water is coming put of the air holes i would suggest the shower pressure is insufficient to allow the Ecocamel head to work as designed.
ours definitely sucks in air as the water rushes past the holes.
as the pressurecdrops, when the shower is turned off, the water then dribbles from the air holes, but only then.
you could try taping over the holes...
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Hi Beatonboys
I'm guessing you mean if the the one pump feeds the other then the flow rate is increased? If the one pump isn't as powerful as the other, I'm guessing the lower powered pump runs first to feed the more powerful pump?
Yes, one pump feeding into the other.
The nature of these types of pumps is that they add energy to the water, so one lifts its energy x amount then the next adds y amount getting the whole up to x + y.
There could be a mismatch in size if the two were very different as the flow through them must when coupled be the same, but here realistically if you place the one rated as the higher flow capacity first it would work best. By their nature, they are pretty tolerant to differences, as long as not wildly out.
In industry, we put these types of pumps in series, ie multi-stage, to get much higher pressures, like borehole pumps to lift water significant heights.
With higher pressure presented to the van's system, the flow achieved will increase but not proportionally. If it achieves double the pressure the flow would increase about 40% [square root factor].
As said earlier one has to accept our leisure systems, using kit aimed at the market can't replicate a good pumped domestic shower operating at water pressures of 70 plus feet head.
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(well, I wasn't, but my better half has lots of long hair...)
Lifestyle choices seem to be the best course here.
Lots of hair = 5* hotel or sites with shower blocks ( we have the same choice)
CL site = Trip to the hairdresser and/or an Ecco shower head.
Much cheaper and saves any costly repairs to the van.
Best of luck with option 1
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Thanks ocsid for your helpful advice.
Have now put the two whale pumps in series, using a 32mm push-fit fitting (perfect fit!) and the water pressure's increased by a third.
With them in parallel they filled a 1tr measuring jug to the brim in 33 seconds - with them in series they filled it in 23 seconds, a big increase!
Next stop is to buy an Ecocamel shower head and that should satisfy her ladyship!
BTW, I've used a sweeping 90 degree 32mm fitting so as to provide a little reservoir in between the output of Pump 1 and input of Pump 2. Does this make sense or is it unnecessary?
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Neat;
I doubt adding a reservoir between them makes any real difference, either way. I would just assemble it in the most convenient to use and or make way.
Theoretically the smoother we change the water velocity the better, like a nice funnelled expansion from pump one into pump two. However, we have what we have so chasing small gains is here not worth the effort IMO
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doesn't happen when your thumb is over the air inlet ! 