Changes

Direct action handpumps are usually made of PVC and other plastics, and are installed on boreholes of limited depth. A plunger is attached to the lower end of a pump rod, beneath the groundwater level. The user moves the pump rod in an up-and-down mo- tion, using a T-bar handle. On the up-stroke, the plunger lifts water into the rising main, and replacement water is drawn into the cylinder through the foot valve. On the down- stroke, the foot valve closes, and water passes through a one-way valve in the plunger and is lifted on the next up-strokeupstroke.  Because direct action handpumps have no mechanical advantage, such as the lever or fly-wheel of a deep-well handpump, direct action pumps can only be used to depths from which an individual can physically lift the column of water (about 12 m). However, the mechanical simplicity, low cost and lightweight construction makes these pumps well equipped to meet O&M ob- jectives objectives at the village level. The pump is operated by moving a handle up and down. As the plunger is located under- water, no priming is needed. Adults, and even children, can pump the water, although if the water table is below 5 m, this may be difficult for children. The pump stand and site must be kept clean. ====Maintenance====Maintenance of direct action pumps is relatively simple and can be taught to users or caretakers, sometimes within a few hours. For preventive maintenance, usually only one or two people are needed. Daily activities consist of checking the pump performance and the appearance of the water (if it is cloudy with silt, the borehole must be cleaned). Annually, the pump should be taken apart and checked. Small repairs include replacing worn cupseals and washers, straightening bent pump rods, and replacing corroded lock nuts. To carry out major repairs (e.g. a broken pump rod or rising main, cracks in the welding of metal parts), skilled help may be needed. O&M can be organized at community level, and since maintenance is relatively simple, good organization will result in a reliable service.'''Potential problems'''* Worn washers, plungers and foot valve parts; * Abrasion of the seal on the PVC cylinder and between the pump rod and rising main; * Broken or damaged handles; * The maximum lift is limited to about 12 m; * The force needed to pump the water may be too great for children, especially if the water table is below 5 m.