A fluidic valve (125, 300, 500, 900, 1000, 1100, 1200, 1300) switches a state of flow of a fluid in a fluid communication channel of a fluid guiding structure (505). Heating a bi-phase valve element (515, 1065, 1215) causes a change a state of the bi-phase valve element from a high viscosity state to a low viscosity state. A bi-phase valve element that clogs the fluid communication channel can be pushed into an expanded portion (135, 320, 520, 915, 1220) of the fluid communication channel by an application of pressure to the fluid while the bi-phase valve element is in the low viscosity state, unclogging the fluid communication channel. A bi-phase valve element can be pushed from a valve element source chamber (550, 1250) into the fluid communication channel by using a pumped fluid entering the source chamber at a pump inlet (551) while the bi-phase valve element is in the low viscosity state, clogging the fluid communication channel.