As we started Planani V1 we already knew we needed warmth for the cabin and for drinking water. While driving we wanted to use the engine cooling water to heat the cabin and the 40 liter boiler water. This saves us energy at arrival. An air heater was therefore no option for us and we didn’t want the sound off the ventilator when everything outside is very quit.
Then 
I started to put all my ideas in switches and relay. This became very fast a very complicated solution. A friend of mine who is an industrial process designer tipped me Siemens Logo.
The
Siemens Logo is a little computer with many wiring possibilities with many inputs and outputs which are all programmable. So with my laptop and the software it was very easy to implement my demands.
When we start the truck a timer in the Logo starts and after 10 minutes the hot engine coolant water starts circulating through the boiler. The automatic switching of the floor heating, booster and boiler are all done with the Logo. So the second unit Planani V2 got a Logo.
Warm water heating
Because we do not want the Diesel, exhaust and the noice in the cabin we mount Eberspacher dieselheater and 3 liter expansion vessel in a storage box underneath the unit. From there the hot water is pumped around through the boiler. When the thermostat demands heat a valve is opened and the hot water is also circulating through the convectors behind the seat as wel as through the pipes in the floor. An extra convector-booster can be switch manually to force airflow and speed up the heating of the cabin.
The engine coolant is connect to a heat exchanger under the cabin so the heating systems from cabin and engine are fully separated. In case of a leakage or other problem the systems wont effect each other.
In the bath cabin we mounted a radiator so we can easy dry our clothes and towels.