If your caravan is getting on in years and it gets a lot of use, you would be well advised to take a look at your hot water supply pipe where it leaves the top of the Truma boiler. The 12mm plastic pipe is described as being ‘semi-rigid’ however with age and constant heating up, the first few inches of the pipe eventually becomes hard and brittle – although it may appear to be sound.
During my recent stay in Spain, as I refilled the Aquaroll one morning, I noticed a dripping of water from behind the skirt rail. I went in the caravan to look inside the bed locker. It was there that I noticed the steady drip from the angled fitting at the top of the boiler. Further examination showed a split close to the end of the plastic pipe. .As the water heats up, it expands and becomes pressurized so is forced out of any weak point. At the time, all I could do was to cut off a few inches of the pipe, and refit it. Only now have I got around to removing two metres of the old pipe and fitting some new stuff. Most caravans use connectors known as John Guest fittings, with the plastic pipe being 12mm outside diameter and 10mm inside.
The fittings rely on the pipe being cut square so that it fits tightly into an O-ring within the fitting. As it is pushed home, it takes with it a collet and stainless steel teeth. When the collet is pulled away from the fitting, the teeth grip the plastic pipe and prevent it being removed. To release the joint, all that is required is to push the collet towards the centre of the fitting, at the same time, pulling on the pipe. Connectors are reusable.
With two meters of new pipe and a new John Guest straight connector, it was a comparatively short job to cut out two metres of old pipe, fit the connector on the cut end and insert the new pipe. Some new zip ties hold the pipes secure. As the van was in storage alongside my house, I could fill the system, allow it to heat up for a while, then check for any leakage.