Making sure that all the system is drained for those winter months and then starting all over in spring it is important to get it right. So, if you are not going to use your motorhome then that task of draining all the water from the boiler and systems just got a whole lot easier. The Truma boiler has a frost protection valve that will be situated under a bench and connected to the water system it can be easily identified by its blue buttons. It can be operated manually but also has an auto drain function to protect the boiler and pipes from having water left in the system.Making sure that all the system is drained for those winter months and then starting all over in spring it is important to get it right. So, if you are not going to use your motorhome then that task of draining all the water from the boiler and systems just got a whole lot easier. The Truma boiler has a frost protection valve that will be situated under a bench and connected to the water system it can be easily identified by its blue buttons. It can be operated manually but also has an auto drain function to protect the boiler and pipes from having water left in the system.