DIY Mechanic: drain-down system

This nifty piece of kit is simple to install and will protect water pipes, says Nigel Hutson

Try this straightforward installation to protect your caravan’s water pipes

SINCE BEING BOUGHT a Floë drain-down kit from APT Innovations as a gift, I am a great believer in its worth. It gets rid of all residual water in the pipes, avoiding the risk of freezing in winter and minimising the chance of bacteria forming. The company has recently launched the Induratec 636 all-in-one kit that integrates a compressor into the caravan water system. Once fitted, it’s simply a case of draining the water out of the system as normal, and then flicking a switch. I recently fitted one to our caravan, and not only does the box include everything that’s needed, plus a very informative DVD, but it is also a simple job, with only basic tools required:

Pipe cutter/secateurs/ Stanley knife Philips screwdriver Wire strippers/cutters Pliers Insulating tape

Before starting, disconnect any mains supply and the caravan’s 12V battery. First, ensure the system is drained before locating the fresh water inlet. The air pipe from the Floë unit needs to be attached as near to the inlet as possible. Then determine whether there’s a non-return valve (NRV) fitted in the water supply pipe. Again, this will be near the water inlet. You will need one, otherwise the compressor won’t be able to pressurise the system. The easiest way to check is to detach the water pipe from the back of the inlet (the connections are usually just push-fit) and then attach a piece of pipe that is long enough for you to blow down. If you can’t blow through it, then there is one, if you can, there isn’t. It may be worth connecting your water pump, too, because occasionally the NRVS don’t work when one is connected, although normally you’ll only use the Floë when the water pump has been disconnected. If you don’t have an NRV fitted, there is one supplied in the kit; the NRV must be inserted into the system with the arrow pointing away from the water inlet. Connect the NRV to the water inlet, replacing the original connection. Next, the T connection (where the air is fed into the water system from the compressor) needs to be inserted into the water line – remember, as close to the water inlet as possible. You’ll need a short section of water pipe between the NRV and the T connection, and then another from the T connection to wherever your water pipe next connects. Finding a suitable location for the Floë compressor unit is the next job. APT doesn’t recommend fixing the unit directly to the caravan wall, because you may run the risk of causing damage. I mounted the unit on a board and then fixed the board to the caravan wall using strong, double-sided tape. To complete the air system, you’ll need some of the black piping supplied in the kit. One end will attach to the T connection and the other to the bit of pipe sticking out of the bottom of the compressor. Depending on where your compressor is mounted, use either the straight or the angled connector (both supplied) between the compressor pipe and the section to the T connection. It’s now time to move on to the electrical side of things. Follow the cable(s) from the rear of the battery box to the main 20A fuse connector. On most caravans, the live (+ve) cable will be brown and blue, and the earth (-ve) white and orange. Once you’ve found this, disconnect the spade terminal on the caravan side (not the battery feed). Next, armed with the wired piggy-back connections in the kit, attach the red male and female spade connectors to the fuse connector and the terminal that you removed from it. All of the supplied connectors are insulated, so once they’re in place, no further insulation is required. There will be a connection in the earth (-ve) cable, too. Separate this connection and insert the black connections in the supplied piggy-back. A 4m fused cable is supplied in the kit. One end plugs into the connection on the piggyback and the other into the connection on the cable from the compressor, and you can’t get these the wrong way around. It would be wise at this point to reconnect the battery and test that the Floë works. With all the taps closed, switch the unit on. APT suggests the compressor will run for 30 seconds or so (ours took a minute to pressurise – each caravan will be different) and make sure the compressor turns off of its own accord. Open a tap and after a short while, when the pressure has dropped, the compressor will kick in again. If the compressor is easy to get to, that’s the job completed. If not, you might want to fit the supplied in-line remote switch. If so, disconnect the battery again. Find a suitable place for mounting the switch. Then run the fused cable to that point. Separate the two wires at the point where the switch will be, and then cut one of them (it doesn’t matter which). Strip the plastic insulation from both ends of the cut wire and crimp them into the switch. Assemble the switch components, mount the switch and reattach the battery.