... fan and blower pressures, filter resistance, air velocity, furnace draft, pressure drop across orifice plates, liquid levels withbubbler systems and pressures in ... in vertical positionConnections: 1⁄8" NPT(F) high and low pressure taps,duplicated-one pair side and one pair backWeight: 240 ... m connecting tube, two 1⁄8" NPT plugs for duplicate pressure taps, two1⁄8" pipe thread to rubber tubing adapters ...