Armstrong S-55-1 STD Cast Iron In-Line Circulating Pump delivers up to 121 GPM at 24 ft of head in a compact inline package designed for hydronic heating, cooling, and domestic water service in commercial systems. It features 3-inch NPT flanges and a 1/2 HP, single-phase motor compatible with 115/230 V at 60 Hz and runs at 1,800 RPM. The cast-iron body and inline configuration support installation in circulating loops and multi-zone systems. Common applications include hydronic heating and cooling circuits, domestic water distribution, multi-zone systems, and general industrial service where reliable circulation is required.
