The Barnes & Jones thermostatic radiator steam trap, model 147A, features a 1" trap connection in an angle pattern. Thermostatic traps are ideal for low pressure heating systems. The thermostatic element expands when steam is present, closing the trap, and contracts when cooler air or condensate is present, opening the trap, which allows the condensate to drain. The 147A is cast bronze, has a 25 psi maximum operating pressure, and an EDR capacity of 4,100 square feet.