World Heat Copper Vented Direct Grade 3 Foam Lagged Cylinders
Direct cylinders were first designed to be used alongside solid fuel appliances and copper back boilers. Today direct cylinders are more commonly used where the economy 7 tariffs are in use. Vented cylinders are available in different grades - 1, 2, and 3. The grade determines the thickness of material required to make the cylinder and thus the amount of pressure the cylinder can withstand.