Return Loop Connection: It is recommended that the return water connections

Return Loop Connection: It is recommended that the return water connections to all low pressure, steam heating boilers supplying a gravity return heating system be so arranged as to form what is known as the "return pipe loop connection," so that the water cannot be forced out of the boiler below the safe water level. This connection is shown in Figure HG-703-1 of Section IV, ASME Heating Boiler Code.