Float valveThe float valve is a simple mechanical liquid level controller. A float detects changes of elevation in the liquid free surface and opens or closes a valve accordingly. Large numbers of small float valves are used in domestic water systems. A float valve maintains the level in the cold water header tank which regulates the pressure of the hot water system. A smaller float valve is fitted to toilet cisterns to measure the flush water. Float valves for domestic cold water applications are made to suit 15 and 22 mm copper pipe. These valves are designated “low pressure” and “high pressure” to cover varying local conditions. The high pressure float valve has a smaller seat area and is capable of working up to 16 barg. In some areas the water supply pressure can be as low as 2 barg