These baseboard systems are positioned low in the room, to take advantage of the fact that hot air rises. So being installed in the lowest point the system assures an even temperature. The heat is obtained from the water and the water comes from a boiler.
Adjusting the heater
Pipes are usually installed in rooms in series and it follows that the first radiator would take the maximum heat. To overcome this problem, the flow of water to the radiators is controlled and the water quantity to the first radiator is controlled and the quantities needed for the next radiators being increased progressively. The adjustments must be made periodically to assure a nice constant temperature. Also the temperature is influenced by furniture or other objects in the room.
Problems with expansion
When it’s hot, the water takes more volume then cold water, so the expansion must be controlled, otherwise the pipes can blow. So to solve this problem, the system allows the returning water to go through an air vessel that takes the increased pressure, compressing the air till pressure get’s equalized. Problems can appear when the vessel get’s filled with water.
The water quantity must be kept at a constant volume, the loss of water being compensated by an overhead tank with a water storage. The heating system is also controlled by a thermostat, controlling the temperature in your home.
Some of the problems that can appear are failure to the pump, boiler shut down, leaks, air entrapment from the heated water, pressure, etc. With some regular maintenance you can avoid these problems.