Whilst I do tend to get a little carried away with the various scenarios in which I would like to spend time in my van there are some benefits to this in terms of creative thinking and useful results. Unfortunately I only thought about posting this after I installed the water tank so illustrations are limited.
I have a romantic vision of spending days on end in remote mountainside locations at the end of a dusty trail. Although the reality of that my not come true quite so immediately I felt the urge to create a water system that could adapt to this (without putting unpleasant tasting chlorine pills in the tank). The tag line being “safe, drinkable water wherever you find yourself”, with of course an obvious(?) caveat being that this doesn’t include salt water. You can retrofit your current system (so long as it’s long enough to fit the UV light). This system will:
- Stage 1 Treatment: Treat any (fresh) water for pathogens – using UV light to prevent
- proliferation of harmful pathogens and therefore preventing illness
- prevent biofilm formation in the tank (reducing risk of Legionnaires disease in warm, around 25 degrees Celsius, conditions)
- Stage 2 Treatment: Filter chemical toxins in the water, according to the manufactures specifications – via a ceramic filter
- Thermal Protection: Reduce risk of freezing via:
- Anti-frost element
Total cost wasn’t in the budget range (coming in at around £350) but I can have 70litres of clean, safe water wherever I am. There are [unaffiliated] links to the various elements below.
This solution has a large number of benefits above other solutions I’ve come across:
- Energy Efficiency
- Stage 1 Runs off 12vRequires <1amp per treatment (each new tank fill) therefore is perfect for off-grid power systems.Stage 2 is passive with zero energy requirements.
- Long life (this very cost effective)
- UV build has an 8,000hr life span (with potential for 80,000 treatments)Ceramic/carbon filter lasts 6 months or more and easily replaceable
- Deals with pathogens AND chemical pollutants. Stops biofilm buildup in the tank (so no need to clean the tanks manually)Reduces risk of freezing (although this requires some additional tweaking)
- Baffled water tank (minimum requirements):
- at least 70cm for the longest side
- inlet /filler hole (1 1/2″ – 40mm) “nut-in” fitting
- an access hatch (big enough to reach into)
- breather outlet
- outlet (water supply side)
- Functional items for tank
As your choice of tank is very specific to the design design of your camper I can only describe how I did mine but point out that it may not be possible if your tank isn’t long enough or the access holes in the tank isn’t amenable to getting the lamp into the tank in the first place. I will admit I got lucky with this, mainly because the baffles had convenient gaps in them and the filler hose hole was drilled where it needed to be (by coincidence, not by any clever forward planning). Given this let me show you the end result (or at least a sketch for now) of what is to be achieved. That way adapting it will be much easier.
Repeating from above, it is important to remember that the UV lamp is quite long and so your tank will need to be at least that long and you will need to be able to access the inside in order to clamp the lamp inside the tank.
In the diagrams below the key points which will help you put everything together are as follows:
- Diagram 1 (installing the access hatch, if not already installed):
- Centred – as access to both sides is likely for fitting key elements as well as securing the lamp internally.
- Large enough to get your hand inside (either side of the baffle if present).
- Diagram 2 (installing UV lamp):
- Entry for the UV lamp via the filler inlet
- Access via maintenance hatch to attach the UV lamp to the inside of the tank
- Hole for the power cable into the tank (which needs sealed with suitable silicone (i.e. safe for drinking water and UV resistant).
- Attachment of lamp holders with appropriate adhesive, or correctly sized fairing/rubber nuts, to the inside of the tank. The rubber nuts are untested but likely to provide a better result in off-road conditions.
- [untested] a UV resistant retainer for the lamp to the holders
- Diagram 3 (installing anti-frost element):
- Location of the element relative to the outlet to assist in preventing the outlet from freezing
- Access to secure element
- Diagram 4 (installing water level gauge):
- Note probes come in different lengths and you should choose according to the tank size (you’re probably smarter than I but I got lucky with my purchase rather than actually plan it that way!)
- Position in the centre to limit inaccuracy when parked on slopes (most likely specific to tank layout as the flatter (height from horizontal) they are the more prone they will be to even smaller angles)
After the initial installation I realised I had fitted the Osmio Water filter at an incorrect point in the system. The diagram below indicates how the system should flow (forgive the pun) in order to ensure that any buildup of a biofilm in the pump (which shouldn’t happen and can be prevented by the odd application of chlorine tablets dropped into the main tank).
An additional point is in the selection of hoses or pipes. Hoses with jubilee clips seem (by some professional builders) as being the least likely to leak and can be taken apart again if necessary with relative ease (although care is required not to have too tight a bend in them as they kink and stop water flow). 15mm compression fit pipes are semi-flexible easy to fit but may be more susceptible to bursting if the pipes freeze, and unless cut well can be prone to leaks. I choose hoses and jubilee clips.
Some other considerations
Whilst this system works great there are still some refinements that I need to consider in my 2.0 version. So from my experience you can most certainly capitalise on this and end up with a more resilient system.
- Positioning of the tank:
- Mine is too high in the van (but the weight is offset by the heavy drawers and kit on the opposite side but not entirely). I would have preferred to have it under (if I could insulate it enough) or flat on the floor. However, this requires the overall build of the garage to be considered prior to tank installation (which I did not do).
- Proximity of the outlet pipes could have been designed to run along heating pipes and this could prevent winter freeze.
- Have the shortest possible lengths of pipe for the outlet (water supply side) to the pump in the colder part of the van. This is particularly so when you have a separate “garage” that is not heated in the same way as the main compartment. Having little or no pipes in this area will help reduce the risk of freezing. In the winter my garage can still get below zero degrees (as my attempt to heat it requires some refinement) in extreme situations.
- I think I will spray-foam the tank in the near future. The foam board is a bit of a pain.
- The pipes will freeze and having them close to the heating system would likely help.
- UV lamp:
- Ideally this should, somehow, be shock mounted. I’ve yet to find some flexible connections (possibly a rubber nut) to attach it to the inside of the tank. The attachments provided also need to be more secure as they aren’t designed for being in a tank that is being bounced around (this would be particularly so if the vehicle is to be driven off-road).