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SETTING THE STROKE ON A HAND PUMP DEAN BENNETT
SUPPLY Before installing the cylinder into the well, below the hand pump, attach your wrench right at the cap, and not in the middle of the cylinder, or you will deform the cylinder. Take the top of the closed top cylinder off and make sure the rod into the plunger assembly is tight. Also check that the bottom of the plunger is on tight. This should be hand tight plus one quarter turn. Depending on the stroke you choose on your hand pump, 5", 7-1/2" or 10", you will set the stroke for 1" to 2" off the bottom check of the cylinder. Push the rod down, and when you hit the bottom check of the cylinder, pull up 1" or 2". If using the shorter stroke, use 2" off the bottom check of the cylinder. Connect to the rod coming down through the hand pump with the handle in the up position, and then lower the handle. The plunger assembly should not hit the top of the cylinder when the handle is clear down. When the handle is up, the plunger is pushed down to the bottom of the cylinder, and when the handle is down, the plunger is pulled up to the top of the stroke in the cylinder. If you are using an open top working barrel #449B cylinder, you should start with the handle up making connection with the plunger pulled up 2" from the bottom check. When setting the stroke, make your adjustment to the point off the bottom check of the cylinder with the handle up, and mark the flat bar where the proper point is. Now push the handle down, and mark the flat bar where the top of your stroke should be. Make sure the up handle position does not allow the plunger to hit the bottom check in the cylinder. The down handle position should not allow the top of the plunger to hit the top of the cylinder, or pull out of the cylinder, in the case of an open top cylinder. Sometimes in a real deep well, the water weight will push the plunger down, raising the handle on the hand pump up. In this situation, there is not much you can do. The water weight is pulling the plunger and rod down, and since you must work this deep for your well, there is not much to do to correct this. When using a hand pump in a deep well, you should use the shorter stroke setting, which will make it easier to pump, and will help to prevent the water weight from pulling the handle up. If necessary, you may need to adjust the length of the pipe or rod to make the handle position proper for your stroke length. Many times it is beneficial to place Vaseline on the cups so that when you place them in the water, they do not swell up enough to lock themselves in the cylinder. Hand pumps don't get pumped constantly, and therefore increase the possibility of this happening. In some cases, using the neoprene rubber cups may be best for a hand pump cylinder, since they are full size, and do not swell up, eliminating the possibility of locking the plunger in place in the cylinder. |