Description: height of the centre of the exhaust pressure gauge; Name: height of exhaust pressure gauge 
Description: Height of the zero or centre position of the outlet manometer, or other point as defined by the manometer calibration ; Name: Height of the outlet manometer
Description: pump h(q) curve where the maximum head (peak point) and shut-off head are not coincidental, or the total head does not decline continuously as the rate of flow increases; Name: stable pump H(Q) curve