Automatic On-board Water Tank fill System (& Tracker) Part 4 (see Sept 2019 for start of this article)

OK, 12 months have passed since I started this article. COVID-19 came along early 2020 and spoilt most the the Seasons camping, so I didn’t get a proper chance to try out the Autofill system. I’ve have just returned from 4 weeks in France – and now at Boris’s command, I have 2 weeks at home to do “whatever I want” – provided I don’t leave home!

VERDICT: The Automatic Water filler system is “Fantastic” – Why didn’t Bailey do this originally? It would not have added much cost to the van, but is a great improvement. No more running out of water, no more flushing airlocks out after running out, no more priming between sites, no more messing about with the lousy Whale Water Inlet with the “dodgy” O rings sealing system!

Basically, having fitted the Crystal 2 water inlet to provide water directly to the on-board tank, the rest was pretty simple (and reasonably cheap). If you want a simple version, just fit a manual switch to the off board pump and off you go. (you also need to arrange a 12v feed to the pump). You can actually find the feed and earth you need on the connectors to the float valves in the tank. This is what I used for my Automatic Filler. As I was not certain that the float valves could handle the current for a pump (I assume Bailey use a relay ???), I used a relay to operate my pump to avoid overloading the existing float contacts. The way I wired the external system draws power from the original bailey supply to the floats. This has the benefit that you can control external & internal pumps from the original Bailey Pump Switch. Position 1 is normal “internal only” pump. Centre is all pumps off, Position 2 is Internal pump as usual and external pump as controlled by the floats and interface box. You could simplify by not having buzzers, not having high/low level options and not having a “local” switch for the external pump. I used a “standard” external “drop in the barrel” pump. It doesn’t need to be super fast as it only keeps the tank filled – the internal pump provides the normal water supply to the taps.

Where I fitted buzzers – these are simple 12v buzzers available for a couple of pounds each on ebay. I used a “warbler” buzzer (2 tone) for the low level alarm (via a switch – I will document this in a separate article). Mine was too loud – I tried reducing the voltage with a resistor – but the best option was “lots of Blu-Tak” over the sounder holes!

Here are photos I took at the time…

You need to buy a new water inlet & connection for an external pump – this is the one I fitted. You will also need buy a standard external filler pump.
Measure this inside wall from the water tank and the floor, to find a suitable location, and then drill a hole through to the outside (as a marker). Then, working from the Outside, put masking tape roughly where you intend to cut…
Place the fitting over the tape with the hole just to the left of the section of “fitting” that sinks into the caravan wall… (see hole through tape – top left) Mark both sides of the fitting…
Use a “Square” to ensure the final fitting looks neat!
.. And again using spirit level (my square has one built in)
Drill the corners to ensure a neat cut-out and using a “Multi tool” (or a pad saw?) cut through the caravan wall (its about 3 cms deep)
Resulting hole…
I used “Mastic Tape” – you could use Mastic from a gun – you could use “Silicon Sealant” – but I went for “traditional” Mastic – but I used tape for convenience… and I already had some!
If you use Mastic Tape – you will need to trim the excess off…
Screw the fitting in and clean off any excess mastic.. White spirit will clean mastic. If you used Silicon – try Meths on a Kitchen towel.
Inside View – NOTE If you have NOT removed your water tank (only reason really to do this is to replace the Tracker Battery) then MAKE SURE you fit the power cable for the pump BEFORE you fit the fitting – otherwise you will find it difficult to access the connector screws!
I bought a small ABS box fitted with screwdown lugs. Inside this I fitted the Relay. I also fitted a sounder internally, (so that I know when the outside pump is running for when it runs out of water). I later moved this outside of the box, because I couldn’t hear it.
I bought one of these boxes from Ebay – Search for “Waterproof ABS Plastic Electronics Project Box Enclosure Hobby Case” or similar. The size I chose was “100 x 70 x 50mm. This size was dictated by the 12v relay I used – and the connector strips.
Relay inside box with slimline sounder – I later fitted an external sounder across the pump connections.
I used a step cutter to cut a hole in the top corner of the water tank.
I used a large cable gland to make a sealed connection into the tank. It needs to be a suitable size to fit the flexible piping to the Water Inlet.
I fitted suitable length cables to the box, before I tried to connect to the existing connections, switches etc. It was easier to make them plenty long enough and have slack, rather than try to cut to size.
Two cables fitted to the original cable connections on the caravan wiring harness. This originally connected to the upper and lower floats in the tank. The float connections will now be taken to the interface box. The connections to the original bailey fitting was made using Crimps to push onto the existing bailey harness.
Note in the photo, the original wiring harness has two BLUE wires on the bottom, a GREY wire top left (in photo) and WHITE wire top right. The new cables: The LEFT cable: Blue=3, Brown=16. The RIGHT cable: Blue=1, Brown-16.
The two control switches I fitted. The top one is On/Off. The lower one is to select “Full Fill” or “Minimum Fill”. I arranged the switch such that pressing the top in for High Fill, and pressing the bottom for “Low” fill. This means mounting the switch “upside down” as switch “open” causes “low” fill only.
Circuit Diagram of Automatic Water Filler System – as installed.

So, I used a Crystal 2 water inlet with filter, and off-board pump (and fittings to fit Crystal 2 connector).

A standard “Automotive” 12v Relay.

A cheap “electronic” buzzer.

A couple of switches – I used the same switches that Bailey used – either buy them from Prima Leisure (official Bailey spares supplier) or get them much cheaper on Ebay!

Automatic On-board Water Tank fill System (& Tracker) Part 1

This article is written around my 2009 Bailey Senator Arizona – but this could probably be done on many other caravans that already have an on-board tank (or you are fitting a tank).

On holiday in France recently, we had problems (yet again), with the O rings of the Whale water inlet (connection to the external barrel), such that I couldn’t even fill the onboard tank properly (which is a pain in itself – messing with manual change-over valves!).

It occurred to me then that if I *could* fill the onboard tank (even by pouring water in the top), I wouldn’t have to bleed the air every time the offboard tank ran out of water! (I have already fitted an Audible alarm to the low level warning light for the onboard tank -which you can’t see on the Bailey, unless you make a point of looking!).

I couldn’t find my spare O rings at the time, but I fixed the external filler using “gas grade” PTFE tape (thicker than the cheap water stuff), that I always keep in the van as part of my “first aid kit” (good to refit worn screws for example). I wrapped it around the damaged / missing O rings.

Anyway – I decided I wanted an “auto-fill” to my on-board tank – similar to a modification I made to my Lunar around 20 years ago.

I looked on the market – there is NOTHING, nothing on Ebay, Nothing on “The Web”, nothing on YouTube, nothing in the Forums on how to do this… No gadgets, no advice, no discussion – maybe I’m the only one that wants this ????

So here is how I did it on my Bailey Senator:

Oh – and BTW if you came here looking for “Tracker” – I will also tell you how to replace the battery in your On-board (hidden) Tracker device. (Bailey Senator Arizona only – Other Bailey’s may be similar!)

Continued in Part 2…