If you are experiencing luke warm water in your caravan, and wondering why your hot water is not very hot, chances are it's the tempering valve.
What's a tempering valve I hear you ask?
In most recent caravans, as in most new houses, the output from the hot water system is mixed with cold water before going to your taps/faucets – mainly for safety reasons so you can't scald yourself. This tempering valve can be adjusted higher or lower depending on your preferences.
Some vans have the valve adjusted too low, or too high, from the factory.
The first thing to check is the actual temperature of the hot water as it leaves the hot water system, before it goes to the tempering valve. The easiest way to do this is to activate the pressure release valve on the hot water system. This runs water directly out of the hot water system, normally through a pipe, and dumps on the ground under your van. Being careful, you can check the temperature of this water. It can be very hot, so be careful. Providing you have hot water here, it indicates your hot water service is running fine.
The tempering valve is normally located under the floor of the van. The will normally look like a 3-way tee piece, with two blue (cold) pipes, and one red (hot) pipe. There's normally a cap or cover which can be removed to access the adjustment mechanism. Adjust according to your preferences and then try the water from the internal taps again!
This can apply to all hot water systems such as Suburban & Truma brands.